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Science

Science 5,059 clues
Practice Science

Overview

Science is one of Jeopardy!'s largest and most consistent topics, approximately 4,900 clues and 67 Final Jeopardy appearances spanning from 1984 to 2026. It skews heavily toward Double Jeopardy (~3,150 DJ vs ~1,680 J clues), reflecting the show's treatment of science as a serious, higher-difficulty topic.

The bare "SCIENCE" category alone accounts for 1,636 clues; one of the largest single-word categories in the show. Other major feeders include GENERAL SCIENCE (289), PHYSICAL SCIENCE (279), -OLOGIES (210), SCIENCE CLASS (113), and SCIENCE FICTION (110). Gender-specific categories are notable: MEN OF SCIENCE (69) and SCIENCE GUYS (55) appear more than three times as often as WOMEN IN SCIENCE (30) and WOMEN OF SCIENCE (11).

The answer pool clusters into clear domains: elements (carbon, hydrogen, oxygen, helium, lithium, iron, mercury, tin, silver, etc.), physics concepts (gravity, inertia, pressure, friction, kinetic energy), astronomy (Saturn, Jupiter, Mars, Venus, the Sun), scientists (Galileo, Newton, Pasteur, Einstein, Darwin), and -ology words (anthropology, meteorology, seismology, paleontology, ecology).

The gimmes: Pasteur (11, 100%), the mantle (10, 100%), absolute zero (10, 100%), chlorophyll (9, 100%), photosynthesis (8, 100%), methane (7, 100%), meteorology (7, 100%), magma (7, 100%), lightning (7, 100%), kinetic (7, 100%), earthquakes (7, 100%), Einstein (7, 100%), plasma (7, 100%), tin (7, 100%), quarks (6, 100%), nitrogen (6, 100%), paleontology (6, 100%), the core (6, 100%).

The stumper zone: order (5 appearances, 80% wrong, taxonomic classification trips everyone up), ammonia (7, 71%), natural selection (6, 67%), fungi (5, 60%), uranium (6, 50%), protons (8, 50%), infrared (6, 50%), fission (6, 50%), ultraviolet (9, 44%), mercury (9, 44%), lithium (10, 40%), Piltdown Man (5, 40%), Dmitri Mendeleev (5, 40%).

Study strategy: Elements are the backbone: they make up roughly 25% of all top answers. Learn each element's symbol, Latin/Greek origin, and distinguishing property. Then master the "Big 5" scientists (Galileo, Newton, Pasteur, Einstein, Darwin) and their key discoveries. For Final Jeopardy, focus on etymology; the origin of scientific terms dominates FJ. Science FJ also loves cross-domain clues connecting science to literature, history, and pop culture.


Elements & Chemistry

Carbon

~23 clues · 65% correct

The #2 most-tested Science answer, but surprisingly difficult at only 65% correct; it comes up in harder DJ clues where contestants overthink. The key hooks: organic chemistry is the chemistry of carbon compounds. The black char on burnt toast is carbon. Anthracite coal is almost entirely carbon. Diamond and graphite are both forms of carbon. Its name comes from the Latin for "charcoal." In 1961 an isotope of carbon (carbon-12) replaced oxygen as the standard for determining atomic weight. Carbon nanotubes (CNTs) appear in modern materials clues.

Hydrogen

~20 clues · 95% correct

A near-perfect gimme. The lightest element, making up the Sun's fuel via fusion. Cavendish called it "inflammable air." Deuterium is "heavy hydrogen." The "H" in pH stands for hydrogen. The Hindenburg disaster is the go-to cultural reference. In the chemical formula for propane (C₃H₈), H is hydrogen.

Oxygen

~18 clues · 78% correct

The most abundant element in Earth's crust (not in the atmosphere, that's nitrogen). Plants produce it through photosynthesis. A Bunsen burner tests for it. Anaerobic organisms don't need it. Cyanosis (bluish skin) results from lack of it.

Helium

~15 clues · 53% correct

Deceptively hard at only 53% correct despite 15 appearances. Named for Helios, the Greek sun god, first detected in the Sun's atmosphere in 1868. The second most abundant element in the universe. A noble gas with the lowest boiling point of any element. Alters the voice when inhaled. Two FJ appearances: "From name of Greek sun god, it is the 2nd most abundant element in the universe" (1985) and "First detected in the Sun's atmosphere in 1868, it got its name from an old word for sun" (2023).

Lithium

~10 clues · 60% correct

The lightest metal and the lightest solid element. Used in batteries and as a mood stabilizer in psychiatry. Element #3 on the periodic table.

Other Key Elements

Iron (10, 80%), The most abundant element in the Earth as a whole (by mass). Its chemical symbol Fe comes from the Latin "ferrum."

Mercury (9, 56%), Tricky because clues alternate between the element and the planet. The only metal that's liquid at room temperature. Named for the Roman messenger god. Symbol Hg from "hydrargyrum" (liquid silver).

Tin (7, 100%), Perfect gimme. Symbol Sn from the Latin "stannum." Used in bronze (an alloy with copper).

Silver (7, 71%), Symbol Ag from the Latin "argentum" (hence Argentina). The best conductor of electricity among all elements.

Uranium (6, 50%), A stumper. Named after the planet Uranus (just as titanium was named for the Titans). Element 92. Key to nuclear fission.

Zinc (6, 67%), Essential trace mineral. Used in galvanization (coating iron/steel to prevent rust).

Nitrogen (6, 100%), A gimme. Makes up about 78% of Earth's atmosphere. Liquid nitrogen freezes things dramatically.

Neon (6, 83%), Noble gas used in illuminated signs. Its name comes from the Greek "neos" (new).

Watch out: Carbon (35% stumper rate despite being answer #2), helium (47% stumper), and uranium (50% stumper) are all far harder than you'd expect. When a clue describes something as "the lightest," think through whether it means lightest element (hydrogen), lightest metal (lithium), or lightest noble gas (helium). When a clue mentions the Sun, consider helium (named for it) before hydrogen.


Physics & Earth Science

Gravity

~26 clues · 92% correct

The single most-tested Science answer. The clue angles cycle through: the force of attraction between masses, what keeps the Moon in orbit, why objects fall at 32 ft/s², the weakest of the four fundamental forces, Newton's 1687 formulation, and "center of gravity" demonstrations. The FJ clue (2009): "According to Chuck Jones, whenever possible, this force of nature was to be Wile E. Coyote's greatest enemy." Know that gravity is the weakest of the four fundamental forces; this surprises contestants.

Inertia

~10 clues · 70% correct

Newton's first law: an object in motion stays in motion, an object at rest stays at rest. The tendency of a body to resist changes in its state of motion.

Pressure

~10 clues · 80% correct

Boyle's Law (pressure and volume are inversely proportional). Measured in atmospheres, bars, millibars, pascals. Pascal's Law governs hydraulics. An isobaric process occurs at constant pressure.

Friction

~9 clues · 89% correct

The force that opposes motion between surfaces. Nearly a gimme. Static friction is greater than kinetic friction.

Thermodynamics

~7 clues · 57% correct

A stumper. The study of heat and energy transfer. The three laws of thermodynamics. Entropy increases in a closed system (second law). Absolute zero is the temperature at which molecular motion ceases.

Absolute Zero

~10 clues · 100% correct

A perfect gimme. 0 Kelvin, −273.15°C, −459.67°F. The theoretical temperature at which all molecular motion stops.

Kinetic

~7 clues · 100% correct

A gimme. Kinetic energy is the energy of motion. From Greek "kinetikos" meaning "of motion."

Key Physics Concepts

Fission (7, 43%), Major stumper. Nuclear fission splits atoms; fusion combines them. The term was borrowed from biology (cell division) in 1939. FJ clue: "This biological term for cell division was borrowed in 1939 to describe a form of energy release." Know the fission/fusion distinction cold.

Protons (8, 50%), Harder than electrons (77% correct). Positively charged subatomic particles in the nucleus. The number of protons defines the element (atomic number).

Natural selection (7, 29%), The #2 stumper after "order." Darwin's mechanism of evolution, organisms with favorable traits survive and reproduce. Contestants may overthink this and guess "evolution" or "survival of the fittest."

Black holes (7, 43%), Physicist John Wheeler coined the term as "a faster way to say 'completely collapsed objects'" (2024 FJ clue). Regions where gravity is so strong that nothing, not even light, can escape.

Earth Science

The mantle (10, 100%), A perfect gimme. Earth's thickest layer, between the crust and the core. The Mohorovičić discontinuity (Moho) marks the boundary between crust and mantle. The D″ (D-double-prime) layer is the lowest part of the mantle.

The core (6, 100%), Another gimme. Earth's innermost layer, mostly iron and nickel.

Magma (7, 100%), Molten rock beneath the surface. When it reaches the surface, it becomes lava.

Earthquakes (7, 100%), A gimme. Measured on the Richter scale (magnitude) and Modified Mercalli scale (intensity). Seismology is the study of earthquakes.

Igneous (10, 80%), One of the three rock types (igneous, sedimentary, metamorphic). Formed from cooled magma or lava. From Latin "ignis" (fire).

Sedimentary (5, 60%), A stumper among rock types. Formed from accumulated sediments, sandstone, limestone, shale.

Watch out: Natural selection (71% wrong), fission (57% wrong), and protons (50% wrong) are all major stumpers. The fission/fusion distinction is critical, "fission" splits (think "fissure"), "fusion" joins (think "fuse"). For natural selection vs. evolution: evolution is the result, natural selection is the mechanism.


Astronomy & Space

The Planets

Saturn (20, 75%), The ringed planet. Cassini discovered the gap in Saturn's rings (Cassini Division). Titan is its largest moon; the only moon in the solar system with a thick atmosphere. The second-largest planet.

Jupiter (20, 85%), The largest planet. The Great Red Spot is a giant storm. The four Galilean moons: Io, Europa, Ganymede, Callisto, discovered by Galileo in 1610. Juno is the spacecraft currently studying it. Europa likely has a subsurface ocean. FJ (2025): "4 of these discovered in the early 1600s were given the names of lovers of a mythological deity."

Mars (12, 83%), Schiaparelli observed "canali" (channels) in 1877, mistranslated as "canals." The farthest terrestrial planet from the Sun. Areology is the study of Mars (from Ares, Greek god of war).

Venus (9, 78%), The hottest planet (runaway greenhouse effect). Earth's "sister planet" in size. Rotates backward (retrograde).

Uranus (8, 75%), Discovered by William Herschel in 1781. Rotates on its side. FJ: Martin Klaproth named uranium after Uranus and titanium after the Titans.

Mercury (8, 88%), Smallest planet, closest to the Sun. Named for the Roman messenger god (fastest planet in orbit).

Pluto (7, 86%), Demoted from planet status in 2006 by the IAU. Now classified as a dwarf planet.

Other Space Topics

The Sun (11, 82%), Powers itself through hydrogen-to-helium fusion. Heliology is the study of the Sun. The most massive object in the solar system. Aphelion is the point when Earth is farthest from the Sun.

The Big Bang (6, 83%), FJ (2005): "Sky & Telescope magazine's contest to replace this term for a single event got 13,000 entries, but chose none." The prevailing cosmological model for the origin of the universe.

A comet (7, 100%), A gimme. FJ (2023): Halley's Comet, "A craft that visited it was named for Giotto, based on the story that 680 years earlier, the painter depicted it as the Star of Bethlehem."

Astrology (8, 75%), Don't confuse with astronomy. The pseudoscience of predicting events from celestial positions. Occasionally tested because students know "astronomy" and second-guess themselves.

Watch out: Saturn (25% wrong) is harder than Jupiter (15% wrong), contestants confuse ring details and moon names. When a clue mentions "canali" or channels, think Mars, not Venice.


Scientists & Discoveries

The Big Five

Galileo (22, 91%), The most-tested scientist in the Science topic. Key hooks: improved the telescope in 1609 and turned it to the heavens; discovered Jupiter's four largest moons (1610); supported Copernicus's heliocentric model; forced to recant before the Inquisition (1633); famous (possibly apocryphal) experiments with falling bodies at the Leaning Tower of Pisa; "Eppur si muove" ("And yet it moves"). The Galileo spacecraft visited Jupiter in the 1990s.

Newton (16, 88%), Three laws of motion, universal gravitation (published in Principia in 1687), co-invented calculus, studied optics and light. Buried in Westminster Abbey. Made his greatest discoveries during the plague years (1665–1666) when Cambridge closed. The apple story is famous but likely embellished.

Pasteur (11, 100%), A perfect gimme. Founded microbiology and immunology. Disproved spontaneous generation. Developed pasteurization (for the wine industry, not milk, a common misconception). Studied silkworm diseases. Developed the rabies vaccine. FJ (2005): "With Napoleon III's support, a physiological chemistry lab was created for him at the Ecole Normale Superieure."

Einstein / Albert Einstein (17 combined, ~87%), Relativity (special and general), E=mc², the photoelectric effect (which won his Nobel Prize; not relativity), Brownian motion. Time dilation, spacetime curvature. Published his "annus mirabilis" papers in 1905.

Darwin (8, 88%), Theory of evolution by natural selection. On the Origin of Species (1859). The voyage of the Beagle. FJ: "Appropriately, this word from Latin for 'unfold' isn't in the first edition of 'Origin of Species', but does appear in later editions" answer: evolution.

Other Key Scientists

Stephen Hawking (8, 88%), A Brief History of Time, black hole radiation (Hawking radiation), ALS diagnosis, Lucasian Professor at Cambridge (same chair as Newton).

Archimedes (10, 70%), "Eureka!" and the bathtub discovery of displacement. The Archimedes screw for lifting water. Principle of buoyancy.

George Washington Carver (7, 71%), Pioneer in agricultural science, especially uses for peanuts, sweet potatoes, and soybeans. Born into slavery.

Copernicus (2 FJ appearances), Heliocentric model. FJ (2010): "The IUPAC named an element for this man born in 1473." FJ (2016): "The symbols for 6 chemical elements spell out his name" Co, P, Er, Ni, Cu, S.

Marie Curie (2 FJ appearances), First person to win two Nobel Prizes (Physics 1903, Chemistry 1911). Polish-born. Her papers are still radioactive, stored in lead boxes. FJ (1985, 2024).

Joseph Priestley, Invented carbonated water as a byproduct of investigating the chemistry of air. Credited with discovering oxygen. FJ (2000).

Dmitri Mendeleev (5, 40%), A stumper. Created the periodic table of elements (1869). Predicted undiscovered elements based on gaps.

The -Ologies (210 clues from this category alone)

Anthropology (11, 73%), The study of human cultures and societies.

Meteorology (7, 100%), A gimme. The study of weather and atmospheric phenomena.

Seismology (6, 83%), The study of earthquakes. Named from Greek "seismos" (shaking).

Paleontology (6, 100%), A gimme. The study of ancient life through fossils. FJ (2023): "Sue" the paleontologist who in 1990 discovered a T. rex in South Dakota.

Ecology (7, 71%), The study of organisms and their environment. From Greek "oikos" (house).

Watch out: Mendeleev (40% wrong) is consistently hard, contestants know the periodic table but can't recall who created it. Archimedes (30% wrong) trips people when clues don't mention the bathtub. Natural selection vs. evolution: "evolution" is Darwin's broader theory; "natural selection" is the specific mechanism, Jeopardy tests both, and contestants confuse them.


Final Jeopardy & Study Patterns

FJ Theme: Etymology & Word Origins

The single most common FJ angle for Science is asking where scientific terms come from: - Atom: In medieval England, meant the smallest unit of time (1/376 of a minute); didn't refer to matter until the 16th century - Entropy: Coined in the 1860s to "sound a bit like energy"; denotes irreversible dispersion of energy - Isotope: Dr. Margaret Todd coined it; from Greek for "equal" and "place" - Satellite: In 1611 Kepler used this word from Latin for "attendant" to describe Galileo's discoveries - Chaos: The word "gas" (coined by chemist van Helmont) comes from this Greek word meaning "unformed mass" - Chromosomes: Named from Greek for "color" and "body" because they become visible when stained - Robotics: Asimov coined the term in 1941, expanding on a word created by Czech playwright Karel Čapek - Fission: Borrowed from biology (cell division) in 1939 for nuclear energy release - Evolution: From Latin for "unfold"; not in the first edition of Origin of Species

FJ Theme: Element Identification

  • Helium: Named for the Greek sun god; 2nd most abundant element in the universe (2 FJ appearances)
  • Californium: The only element named for a U.S. state
  • Titanium: Klaproth named uranium after Uranus and this element after Uranus' children (the Titans)
  • Tungsten: Its symbol (W) comes from its German name, Wolfram
  • Iodine or helium: The two elements whose symbol is a pronoun (I and He)

FJ Theme: Scientist Biography

  • Marie Curie: First person to win two Nobel Prizes; papers stored in lead boxes (2 FJ appearances)
  • Copernicus: Element copernicium named for him; 6 element symbols spell his name (2 FJ appearances)
  • Pasteur: Physiological chemistry lab at Ecole Normale Superieure
  • Johannes Kepler: Wrote Somnium, an early work of science fiction (1634)
  • Joseph Priestley: Invented carbonated water investigating the chemistry of air
  • Alfred Nobel: "Perhaps my factories will put an end to war sooner than your congresses" (1891)
  • Nikola Tesla and Thomas Edison: "The Life-Long Feud That Electrified the World"
  • Luther Burbank: Autobiography Harvest of the Years (1927)
  • Mary Leakey: Autobiography Disclosing The Past (1984)

FJ Theme: Science & Literature Crossovers

  • Silent Spring: Keats' line "The sedge is withered from the lake, and no birds sing" inspired Rachel Carson's title
  • The Lost World: Conan Doyle novel reissued with a Michael Crichton introduction
  • The War of the Worlds: "The Falling Star" is Chapter 2 of this 1898 H.G. Wells novel
  • Amazing Stories: Groundbreaking sci-fi magazine (1926) and TV anthology series (1985)
  • Tribbles: Star Trek creatures inspired by rabbits multiplying in Australia
  • A butterfly: In a 1952 Ray Bradbury story, a time traveler finds a dead one on his shoe

FJ Theme: Science Records & Firsts

  • Gravity: Wile E. Coyote's greatest enemy (Chuck Jones)
  • Halley's Comet: Giotto spacecraft named for painter who depicted it as Star of Bethlehem
  • The Human Genome Project: 739MB file of As, Ts, Gs, and Cs; Clinton called it "the most wondrous map ever produced"
  • Barometer: Robert Boyle renamed the Torricellian Tube
  • Gyroscope: Jean Foucault made one to prove the Earth rotated
  • Berkeley: Only U.S. city with an element named for it
  • A vacuum: Refractive index of exactly 1.0000

The Stumper Reference

Answer Wrong % What trips contestants up
order 80% Taxonomic rank; not an intuitive answer
ammonia 71% Chemical compound, contestants guess other chemicals
natural selection 67% Confused with "evolution" or "survival of the fittest"
fungi 60% Kingdom classification; not plant, not animal
uranium 50% Can't recall element name from clue description
protons 50% Confused with electrons or neutrons
infrared 50% Confused with ultraviolet, contestants mix up the spectrum
fission 50% Confused with fusion; the split/join distinction
ultraviolet 44% Same confusion as infrared, from the other direction
mercury 44% Ambiguity: element vs. planet vs. Roman god
lithium 40% "Lightest metal" contestants guess aluminum or sodium
Piltdown Man 40% Famous hoax, contestants can't recall the name
Dmitri Mendeleev 40% Created the periodic table but name is hard to recall
carbon 35% Appears in hard DJ clues; contestants overthink it
water 36% Too obvious-seeming; contestants second-guess themselves
inertia 30% Confused with momentum or friction

Strategy for stumpers: Many Science stumpers come from second-guessing. When a clue describes a fundamental concept (gravity, carbon, water, natural selection), trust your first instinct; the "obvious" answer is usually correct. For spectrum confusion (infrared vs. ultraviolet), remember: infra = below (below red = longer wavelengths, heat), ultra = beyond (beyond violet = shorter wavelengths, sunburn). For fission vs. fusion: fission = fissure = split; fusion = fuse = join.

Gimme Answers

top 50

Memorize these and recognize 10.1% of all Science clues.

#AnswerCountSample Clue
1 hydrogen 23 A tokamak plasma nuclear reactor superheats isotopic nuclei of this element so that they fuse, releasing energy
2 gravity 21 At the Earth's surface, this force produces acceleration of about 32 feet per second per second
3 Galileo 18 In 1589 he began experimenting in Pisa with falling objects using inclined planes to slow the rate of descent
4 carbon 18 Graphite is a soft form of this element
5 Sir Isaac Newton 16 A rocket's thrust may be measured in units named for this man whose laws of motion explain rocketry
6 Jupiter 15 Carpo, Kale & Eirene are 3 of the 79 known moons orbiting this planet
7 carbon dioxide 15 Add 4 tbsp, vinegar & 3 tbsp. baking soda to a glass of water & this gas will make raisins bounce in it
8 chromosomes 14 A zygote has the full or diploid number of these
9 the Sun 14 Heliology is the study of light from this source
10 Saturn 13 In 1672, Cassini discovered Rhea, the second-largest moon of this planet, now discover Rhea for yourself via the Cassini spacecraft
11 oxygen 13 Nitrogen makes up around 78% of the atmosphere; this gas, only about 20%
12 Albert Einstein 13 In 1905 this way cool scientist published his special theory of relativity
13 Water 12 The Earth is the only planet in our solar system to have 2/3 of its surface covered by this
14 Mercury 12 CFLs, compact fluorescent lamps, light up by exciting atoms of this silver-colored element
15 static electricity 12 This can build up after a good hair brushing, & when you remove a wool hat, it can make your hair stand on end
16 Mars 11 Areology is the observation & study of this planet
17 electrons 11 In the body, free radicals are atoms that are unstable & can damage cells by stealing one of these particles from nearby molecules
18 light 10 By definition, bioluminescence is the production of this by living organisms
19 igneous 10 Of the 3 main classes of rock, this one is further divided into plutonic & volcanic types
20 Uranium 9 It was an atom of this element that Otto Hahn split in 1938
21 Pasteur 9 He had a pretty good 19th century run, including saving France's beer, wine & silk industries
22 lead 9 One of the heaviest of metals, it's often used in alloys called Babbitt metals to make bearings
23 helium 9 It has the lowest boiling point of any element, -452 degrees Fahrenheit
24 an electron 9 Physicist J.J. Thomson discovered this subatomic particle in 1897
25 natural gas 9 This type of fossil fuel is primarily methane
26 Dmitri Mendeleev 9 Nobel, Lise Meitner & this man are the 3 non-Nobel Prize-winning scientists who have chemical elements named for them
27 tin 8 The Latin word for this element is stannum
28 pressure 8 The unit of measure for this force is the bar or millibar
29 iron 8 Binding energy binds a nucleus together; this abundant metallic element has the greatest & is the most stable
30 DNA 8 This 3-letter substance that carries the genetic code directs the production of RNA
31 coal 8 BTU is the stock symbol of Peabody Energy, which mines for this black stuff
32 Archimedes 8 This ancient Greek who loved the lever established statics, the study of a body at equilibrium
33 anthropology 8 At Brown Jessaca Leinaweaver, the chair of this department aims to study "humanity, past & present"
34 amber 8 When rubbed with a cloth, this yellow fossil resin becomes electrically charged
35 absolute zero 8 -273 Celsius
36 the mantle 7 The Mohorovicic Discontinuity is the boundary between the Earth's crust & this layer
37 seismology 7 Charles Richter taught this -ology at Caltech from 1937 to 1970
38 rubber 7 Magid makes its A.R.C. insulating gloves from this natural material & they'll protect you up to 1,000 volts
39 quartz 7 In 1929 the application of crystals of this mineral allowed for electric timepieces
40 Psychology 7 William James' 1890 "The Principles of" this is considered a classic in the field
41 photosynthesis 7 In plants, light energy from the sun is converted into chemical energy via this process
42 meteorology 7 It's the study of the atmosphere & weather, not of shooting stars
43 metamorphic 7 Marble is classified as this type of rock because it changed from limestone due to heat & pressure
44 lithium 7 The atoms in your body are billions of years old; the hydrogen & this lightest metal may date to the Big Bang
45 inertia 7 ( Sarah demonstrates the clue in the science lab.) The sideways pull of the hoop won't generate enough friction to pull the cap along with it, so the ...
46 friction 7 There are static & kinetic types of this force on objects that are in contact with each other
47 stem cells 7 Korea's Woo-Suk Hwang faked a 2004 breakthrough in getting these mighty medical things from cloned embryos
48 Jean Foucault 7 In 1851 this "swinger" used a pendulum to show that the Earth rotates on its axis
49 Venus 6 Radar images taken by the Magellan spacecraft in the 1990s helped determine that this planet has around 85,000 volcanoes
50 Uranus 6 This outer planet discovered by Herschel has a 98-degree axial tilt & solstices 42 years apart

Sub-Areas

470
answers to learn
36 Must-Know
126 Should-Know
308 Worth Knowing

Must-Know Answers

These appear 8+ times. Memorize these first.

hydrogen 23 gravity 21 Galileo 18 carbon 18 Sir Isaac Newton 18 Jupiter 15 carbon dioxide 15 liquid oxygen 15 chromosomes 14 the Sun 14 Saturn 13 Albert Einstein 13 Water 12 Mercury 12 static electricity 12 Mars 11 electrons 11 the electron 11 light 10 igneous 10 Uranium 9 Pasteur 9 lead 9 helium 9 natural gas 9 Dmitri Mendeleev 9 tin 8 pressure 8 iron 8 DNA 8 coal 8 Archimedes 8 anthropology 8 amber 8 absolute zero 8 gamma radiation 8

Answers by Category

Jump to: Chemistry / Elements | Astronomy / Space | Biology / Animals | Other | Math / Physics | Earth Science | Medicine / Health | Botany / Plants

Chemistry / Elements

235 answers | 888 clues
Must-Know (18)
Sir Isaac Newton 18x $478 avg J:10 DJ:8
J $400 1995 He outlines his 3 laws of motion in "Philosophiae Naturalis Principia Mathematica"
J $500 1998 A rocket's thrust may be measured in units named for this man whose laws of motion explain rocketry
DJ $600 1999 In 1987 the Smithsonian celebrated the 300th anniversary of this scientist's "Principia"
liquid oxygen 15x 20.0% stumper $500 avg J:5 DJ:10
J $300 1993 Used in rocket propulsion, LOX stands for this
DJ $600 1992 Cane sugar is a chemical compound consisting of carbon, hydrogen & this element
DJ $1,200 2010 Rocket pioneer Robert Goddard discovered the best liquid fuel was a combination of gasoline and this, aka LOx
chromosomes 14x 7.1% stumper $521 avg J:4 DJ:10
J $200 1997 Human beings normally have 46 of these in most of their cells
DJ $600 1996 They're the tiny threadlike structures that carry the genes - you have 23 pairs
DJ $1,200 2006 These DNA-bearing structures have caps called telomeres; learn to lengthen those & we'll all live forever
Albert Einstein 13x 7.7% stumper $354 avg J:6 DJ:7
J $200 2005 In 1933 he joined the Institute for Advanced Study in Princeton, N.J.; he became a U.S. citizen in 1940
DJ $600 1991 In 1905 he was the first to propose the existence of particles of light called photons
DJ $1,000 1997 In 1905 this physicist proposed that photons were the carriers of electromagnetic energy
static electricity 12x 8.3% stumper $467 avg J:7 DJ:5
DJ $200 1986 Developed in the 18th century, the Leyden jar stores this
J $600 2024 1880: Jacques & Pierre Curie discover "piezo-" this, emitted by certain crystals when they're put under pressure
DJ $1,200 2013 It's annoying when you walk across carpet & touch metal but helpful when Xerox machines use it to make copies
electrons 11x 9.1% stumper $873 avg J:1 DJ:10
DJ $200 1996 In an atom these elementary particles spin around the nucleus
DJ $600 1988 From Greek for "amber", these subatomic particles were discovered in cathode rays in 1895
DJ $1,600 2011 The Schottky effect is a type of increase in the discharge of these subatomic particles from a heated surface
light 10x $310 avg J:6 DJ:4
J $100 1994 When exposed to ultraviolet radiation, a phosphoric substance will emit this
J $600 2003 2001: Researchers produce pulses of this that last 650 billionths of a billionth of a second
J $200 2014 By definition, bioluminescence is the production of this by living organisms
Pasteur 9x $689 avg J:4 DJ:5
J $400 2002 In 1888 this French bacteriologist founded an institute in Paris to continue his rabies research
J $600 2013 This 19th century chemist saved France's beer, wine & silk industries
J $1,000 2026 In the 1860s he presented to the French Academy of Sciences his work undermining the idea of spontaneous generation
lead 9x 33.3% stumper $978 avg J:4 DJ:5
DJ $200 1992 From the Latin plumbum, Pb is the chemical symbol for this
J $600 2015 This element is "le plomb"; get it out!
DJ $2,000 2024 About 1.5% of any quantity of the isotope uranium-238 decays to this element every 100 million years
natural gas 9x 11.1% stumper $711 avg J:1 DJ:8
DJ $200 2000 Above its critical temperature, a liquid becomes this
DJ $600 1985 The Netherlands is the world's 3rd-largest producer of this energy source
DJ $1,600 2022 Boyle's law states that the pressure of this varies inversely with its volume at constant temperature
Dmitri Mendeleev 9x 33.3% stumper $1,244 avg DJ:9
DJ $800 2000 This Russian chemist used his periodic law to predict the properties of 3 then unknown elements
DJ $1,000 2001 In 1869 this Russian chemist published his periodic table
DJ $1,000 2001 The element named for him wasn't one of the ones he left a gap for in the periodic table; it came in at 101
tin 8x $738 avg J:4 DJ:4
J $300 1998 You add this element to copper & zinc to get bronze
J $600 2021 Stannum is the Latin word for this, which explains Sn as its chemical symbol
J $1,100 DD 2019 The Latin word for this element is stannum
pressure 8x 25.0% stumper $2,538 avg J:2 DJ:6
DJ $400 1997 According to Boyle's Law, when a gas is compressed to half its size, this doubles
J $500 1988 The unit of measure for this force is the bar or millibar
DJ $1,200 2011 ( Sarah of the Clue Crew gives the clue as she and Kelly demonstrate a potato gun.) A potato gun demonstrates Boyle's Law using a simple tube & a stick; pushing the stick reduces the volume of air & increases this 8-letter term, making the potato go ...
DNA 8x $543 avg J:1 DJ:6 FJ:1
DJ $400 2024 The novel "The Gold Bug Variations" has a double-stranded plot, intertwining Bach's music & cracking the code of this molecule
DJ $600 1993 The oldest strand of this substance extracted is from a 25-million-year- old termite
FJ 2013 For a 1953 paper Odile Crick drew the diagram showing the structure of this
coal 8x 12.5% stumper $575 avg J:2 DJ:6
DJ $200 1992 The main types of this fuel are peat, lignite, bituminous & anthracite
J $600 DD 2006 2/3 of the world's steel is produced using this as fuel
DJ $1,200 2015 A scrubber is a device primarily to remove sulfur before gases go up the smokestacks of plants burning this fuel
Archimedes 8x 25.0% stumper $962 avg J:2 DJ:6
DJ $400 2024 A hydrostatic principle is named for this Greek who lived much of his life in Syracuse, Sicily, then a Greek city-state
J $500 1989 Known for his principle of displacement, he's been called "The Father of Experimental Science"
J $1,000 2022 This Greek gave his name to the law that says a body in fluid is acted on by force proportional to how much fluid it displaces
absolute zero 8x $538 avg J:3 DJ:5
DJ $400 2019 2-word name for what in theory is the lowest possible temperature
J $500 1984 Name given to temperature -273.15 C
J $1,000 2020 It's equal to -459.67 degrees Fahrenheit
gamma radiation 8x 12.5% stumper $750 avg J:1 DJ:7
DJ $200 1993 In physics a rad is the unit used to measure the amount of this absorbed by matter
DJ $600 1997 It's measured in rads
DJ $1,200 2004 Called the most energetic form of electromagnetic radiation, it had a Bruce Banner year on film in 2003
Should-Know (73)
the mantle 7x $600 avg J:2 DJ:5
DJ $200 1996 It's the term for the portion of the Earth between the crust & the core
J $800 2024 What's called the Moho discontinuity inside the Earth separates the crust from this interior section
DJ $1,200 2022 This region of the inner Earth is prone to hot spots; volcanoes can form above them
rubber 7x 42.9% stumper $629 avg J:3 DJ:4
J $100 1991 Vulcanization increases the hardness of this by heating it with sulphur
DJ $1,600 2024 In the 19th century Charles Macintosh mixed a solvent called naphtha with this substance to make a waterproof material
J $200 1991 Joseph Priestley gave this name to some tree sap that could wipe out pencil marks
quartz 7x 28.6% stumper $1,229 avg DJ:7
DJ $400 2019 When exposed to electricity, this mineral vibrates at regular intervals, so it's used in wristwatches to keep accurate time
DJ $600 1992 Crystals of this mineral are used in wave transmitters of radio & TV sets
DJ $1,000 1992 Many of the gems sold as topaz are actually the citrine variety of this stone
metamorphic 7x 14.3% stumper $1,586 avg J:3 DJ:4
J $600 2022 Let's change the subject & talk about this class of rocks including gneiss & soapstone that gets changed atom by atom over time
J $900 DD 1999 Since limestone undergoes changes to become marble, marble is classified as this type of rock
DJ $600 1994 Changes in the Earth may eventually cause igneous & sedimentary rocks to become this type
lithium 7x 14.3% stumper $1,200 avg DJ:7
DJ $800 2021 It has atomic number 3 as the least dense of all metals & number 34 as a SiriusXM channel for '90s tunes
DJ $1,000 1994 This lightest of all metals was discovered by Swedish chemist Johann Arfvedson in 1817
DJ $800 2009 The major source of this treatment for bipolar disorder is mined in North Carolina
friction 7x $771 avg J:2 DJ:5
J $200 2018 It's the resistance that opposes the motion of one surface across another
DJ $800 2013 Hockey pucks are frozen before a game to reduce this motion-resisting force
DJ $1,200 2019 You can't use a Carnot engine to power your car—it's an ideal one that loses no heat via this resisting force
nuclear fission 7x 16.7% stumper $767 avg J:1 DJ:5 FJ:1
DJ $400 2009 In 1939 physicist Lise Meitner & her nephew Otto Frisch coined this term referring to the splitting of an atom's nucleus
DJ $600 1988 In biology it's cells splitting & making identical offspring, but in physics, it's nuclei splitting, making energy
DJ $1,600 2022 It's the process by which an atomic nucleus splits into 2 smaller nuclei, or how certain single-celled organisms reproduce
stem cells 7x 14.3% stumper $814 avg J:4 DJ:3
J $200 2007 These cells from human embryos can grow into any type of tissue & may someday cure diabetes & Alzheimer's
J $500 1984 Cytology is the study of these biological building blocks
J $1,000 2024 1965: Leonard Hayflick shows that these can divide & reproduce only a finite number of times before dying
Jean Foucault 7x 57.1% stumper $1,029 avg J:3 DJ:4
J $200 2009 The axial rotation of the Earth seems to shift the plane of motion of this scientist's pendulum
J $800 2026 The Central Rotunda of the Griffith Park Observatory showcases the pendulum experiment tried by this man in 1851
DJ $1,000 1991 This man, known for his pendulum, made the first gyroscope in 1852
silver 6x 16.7% stumper $383 avg J:3 DJ:3
J $100 1988 Something described as argentiferous contains or produces this metal
DJ $600 1985 The photographic industry is world's largest user of this precious metal
J $200 2021 Argentiferous means containing or producing this metal
salt 6x 33.3% stumper $683 avg J:4 DJ:2
J $100 1996 It's the more common name for sodium chloride
DJ $1,200 2021 Pass the this, defined as a substance produced by the reaction of a base & an acid
J $200 2010 To combat hypothyroidism, iodine was first added in the 1920s to this common seasoning
Potassium 6x $683 avg J:3 DJ:3
J $300 1997 This second-lightest metal, symbol K, is so soft it can be cut with a knife
J $600 2022 Bananas have a tiny amount of radioactivity due to this element, which can emit.01 millirems of radiation
DJ $1,600 2009 "To protect taste" Diet Coke adds some "K" to the mix: this element
pollen 6x $350 avg J:4 DJ:2
J $200 2016 The ragweed variety of this material is seen here under the microscope—achoo!
DJ $600 1996 Honeybees get their sugar from nectar & their protein & fat from this
J $200 2009 Breezes often transfer these tiny grains from male flower parts to female seed cones
kinetic 6x $950 avg J:2 DJ:4
J $500 DD 1997 It's the type of energy a body possesses by virtue of its movement
DJ $1,000 1993 It's the type of energy exhibited by a flying baseball or an object falling to the ground
J $600 2018 This adjective from the Greek for "moving" describes the mechanical energy of an object due to motion
earthquakes 6x $200 avg J:5 DJ:1
J $100 1989 In the 1st century A.D. the Chinese invented the 1st seismometer to detect these
J $100 1987 Data from resistivity gauges, gravimeters, & creep meters are being used in efforts to predict these
J $200 2018 Curtains made of carbon fiber rods are specifically designed to help buildings withstand these
Darwin 6x $633 avg J:2 DJ:4
J $200 2013 He let his theory evolve for 20 years before going public in 1858
J $800 2007 8 years before "The Origin of Species" was published, this British naturalist wrote a paper on barnacles
DJ $1,200 2005 While serving as secretary of the Geological Society of London, 1839-41, he wrote the "Journal of Researches"
Celsius 6x 16.7% stumper $483 avg J:3 DJ:3
DJ $200 1995 In 1742 he described his centigrade thermometer before the Swedish Academy of Sciences
J $500 1985 Till later scientists reversed his scale, he said: 0º equals boiling, 100º equals freezing
J $400 2022 A Swedish astronomer gave his name to this temperature scale
algae 6x 16.7% stumper $400 avg J:4 DJ:2
J $100 1993 A botanist could tell you that algology is the study of these
J $500 2000 The monera kingdom consists of bacteria & the blue-green species of this
J $200 2008 One day soon we may go even greener with fuel made from these green goopy simple aquatic organisms
Niels Bohr 6x $1,200 avg J:1 DJ:5
J $800 2013 In 1957 this Danish physicist became the first recipient of the USA's Atoms for Peace Award
DJ $1,000 1996 This Danish physicist won a Nobel Prize in 1922 & his son won one in 1975
DJ $1,200 2008 In 1920, he was named director of the Institute of Theoretical Physics in Copenhagen
Enrico Fermi 6x $1,050 avg J:3 DJ:3
J $300 1988 While "FM" means frequency modulation, Fm is an element named for this Italian atomic physicist
J $1,000 2020 Who better to write "Thermodynamics" than this Italian-American physicist who helped create the first nuclear chain reaction
J $1,000 2002 This Italian-born physicist first split the atom in 1934, although he didn't know it for 4 more years
a diamond 6x 16.7% stumper $417 avg J:1 DJ:5
DJ $200 1992 Carbonado is an impure form of this mineral used for drills & abrasives
DJ $800 1990 This mineral comes after No. 9, corundum, on the Mohs scale
DJ $400 2013 At 10, this mineral is the hardest on the Mohs scale
sulfur 5x 40.0% stumper $900 avg J:2 DJ:3
J $300 1996 This yellow element is found in gunpowder & matches & is used in vulcanizing rubber
DJ $1,000 1988 Nathaniel Hayward sold Chas. Goodyear his process for treating rubber with this element
J $400 1987 This element, No. 16, is always found near volcanoes, bringing true meaning to "fire & brimstone"
Rachel Carson 5x 40.0% stumper $740 avg J:2 DJ:3
J $200 1994 A friend whose bird sanctuary had been sprayed with DDT sparked her to write "Silent Spring"
DJ $800 1997 This author of "The Sea Around Us" taught zoology at the University of Maryland 1931-36
DJ $1,200 2011 During the depression, this marine biologist & ecologist wrote radio scripts for the U.S. Bureau of Fisheries
protons 5x 20.0% stumper $840 avg J:1 DJ:4
DJ $400 2022 The atomic number of an element is determined by the number of these in one atom of it
DJ $600 1999 Mass number is defined as the number of neutrons & these particles in an atom's nucleus
DJ $1,600 2008 ( Kelly of the Clue Crew rubs a balloon on her hair in the Jeopardy! science lab.) Rubbing a balloon builds up electrons that then attract this type of particle in a metal can, from the Greek for "first"
natural selection 5x 60.0% stumper $680 avg J:1 DJ:4
DJ $400 1989 Darwin explained how the fittest of each species survived through this evolutionary process
DJ $600 1992 Darwinism is the idea that evolution took place by this process
DJ $1,200 2008 Darwin defined it as "preservation of favorable variations and the rejection of injurious variations"
iodine 5x 20.0% stumper $1,020 avg J:2 DJ:3
J $300 2000 While compounds of this element are added to table salt, in its pure form it's quite poisonous
DJ $800 1993 Seafood is a good source of this element necessary for the formation of thyroid hormones
DJ $1,600 2013 A bluish-black solid at room temperature, this halogen changes into a purple vapor when heated
Heisenberg 5x $1,400 avg J:1 DJ:4
DJ $800 2025 (Melissa Peterman presents the clue.) After being on "Young Sheldon" for 30-plus episodes, I can finally say it—a subatomic particle's position & momentum can't be accurately determined at the same time, sayshis Uncertainty Principle. Oh, that felt g...
J $1,000 2008 His uncertainty principle says a particle's position & momentum can't be known simultaneously
DJ $1,200 2024 In a 1927 paper he wrote, "We simply cannot know the present in principle in all its parameters"
heat 5x 20.0% stumper $680 avg J:1 DJ:4
DJ $400 2006 Combustion is an example of an exothermic reaction, one in which this is released
DJ $600 1991 A chemical reaction that absorbs this is endothermic; that gives it off, exothermic
DJ $1,200 2010 The second law of thermodynamics says that this will of its own accord only move to a colder object
glaciers 5x $220 avg J:3 DJ:2
J $100 1996 Drumlins are elongated, elliptical hills formed at the edges of these moving ice masses
J $200 1993 Erosion from these created fjords & drumlins
J $200 1991 The snow that falls on these moving ice masses goes through a stage called névé or firn
George Washington Carver 5x 20.0% stumper $840 avg DJ:5
DJ $400 2001 In 1897 this son of slaves discovered 3 new species of fungi which are named for him, including Taphrina carveri
DJ $800 2016 This Missouri man who loved to work for peanuts also developed a type of synthetic marble made from wood shavings
DJ $1,000 1987 Born in 1861, this scientist worked with Henry Ford to make rubber from milk of goldenrod
geology 5x 20.0% stumper $560 avg J:1 DJ:4
J $200 1998 The name of this science comes from 2 Greek words meaning "Earth discussion"
DJ $1,000 1984 Stratigraphy is a branch of this science
DJ $200 1993 Branches of this earth science include petrology & seismology
genes 5x $660 avg J:1 DJ:4
DJ $400 2013 In 2013 the Supreme Court ruled that human ones can't be patented, though synthetic versions can
J $500 1994 Barbara McClintock discovered that these can move from one place to another on plant chromosomes
DJ $1,600 2019 Jennifer Doudna & Emmanuelle Charpentier are co-inventors of the revolutionary tool CRISPR to edit these in the body
fermentation 5x 20.0% stumper $860 avg J:1 DJ:4
DJ $100 DD 1995 This is defined as the breakdown of glucose or other sugars by yeast or bacteria in the absence of oxygen
DJ $800 2021 Our pal Louis Pasteur used this word to describe what happens when yeast functions anaerobically
DJ $1,200 2007 Zymurgy is the chemistry branch that deals with this process in which sugar is converted into alcohol
ecology 5x 40.0% stumper $1,000 avg J:3 DJ:2
J $400 2016 Before global warming was a thing, Marvin Gaye put this -ology into the subtitle of his song "Mercy Mercy Me"
DJ $800 2017 It's the -ology associated with the symbol seen here that was created back in the '60s
J $3,000 DD 2021 A German zoologist coined the name of this branch of biology that studies the relationship between organisms & their environments
chlorophyll 5x $1,300 avg J:1 DJ:4
J $100 1997 This green plant pigment is also found in algae & in some bacteria
DJ $800 2009 The name of this green pigment found in plants is partly from the Greek for "green"
DJ $5,000 DD 2012 This pigment comes in different letter types; the C version is found in algae
ammonia 5x 60.0% stumper $1,160 avg J:1 DJ:4
J $400 1993 About 70% of this pungent gas produced is converted into fertilizer
DJ $600 1991 In the Haber process hydrogen & nitrogen combine to form this pungent gas
DJ $1,200 2011 The Haber process uses nitrogen & hydrogen to synthetically produce this pungent gas
a vacuum 5x $900 avg J:1 DJ:3 FJ:1
J $400 1990 Term for a space in which there are no atoms or molecules; a perfect one is unobtainable
DJ $1,200 2011 ( Sarah of the Clue Crew performs a science demonstration.) You'd expect the paper to fly up when extreme pressure is applied, but instead... the wood breaks; air couldn't flow in quickly enough between the paper, the wood & the table, so a partial t...
FJ 2003 Some refractive index numbers for you now: diamond, 2.42; air, 1.0003, this, 1.0000
the nucleus 5x $520 avg J:2 DJ:3
DJ $200 1996 Almost the entire mass of an atom is contained in this central portion
DJ $600 1993 It's the most massive part of an atom
DJ $1,200 2003 In 1963 Maria Goeppert Mayer received a Nobel Prize in Physics for her "shell model" of this part of an atom
an ion 5x 20.0% stumper $460 avg J:3 DJ:2
J $300 1997 It's defined as an atom or group of atoms that has an electrical charge
J $600 2019 This type of atom is formed by the loss or gain of electrons
J $400 1998 A neutral atom will become one of these when it gains or loses an electron
work 4x 50.0% stumper $1,275 avg DJ:4
DJ $800 2000 To scientists, it's force times distance; to Twain, it's "whatever a body is obliged to do"
DJ $1,200 2015 Force times distance gives you this, commonly expressed in joules
DJ $1,500 DD 1988 A foot-candle is a unit of illumination & a foot-pound is a unit of this
viscosity 4x $1,500 avg DJ:4
DJ $800 1992 The resistance of a fluid to flow; syrup has a greater degree of it than water
DJ $1,600 2016 (Jimmy of the Clue Crew shows an animation on the monitor.) Fluids vary in the degree of friction between their molecules, leading them to also vary in their degree of resistance to flow—this 9-letter word
DJ $1,600 2003 ( Sarah of the Clue Crew demonstrates in the lab.) From the Latin for "sticky", it's the resistance of a fluid to flowing
tungsten 4x $1,250 avg DJ:4
DJ $800 2016 This metal was discovered by 2 Spanish chemists in 1783 in samples of the mineral wolframite
DJ $1,000 1997 This gray metal is used in spark plugs & x-ray tubes as well as filaments
DJ $1,600 2009 This dense element's name is from the Swedish for "heavy stone"; most of Europe calls it wolfram
thermodynamics 4x 50.0% stumper $1,350 avg J:1 DJ:3
DJ $800 1991 The relationship between heat, work & energy is the basis of this physics branch
J $1,000 2021 As Homer Simpson said, "In this house we obey the laws of" this relationship between heat & mechanical energy
DJ $1,200 2024 The law of conservation of energy is considered the first of the 3 laws of this 14-letter science
theology 4x $450 avg J:2 DJ:2
J $200 2016 A Th.D. from Duke Divinity School is a doctor of this
J $800 2011 In 1512 Martin Luther earned the degree doctor of this
DJ $400 1993 Martin Luther & Albert Schweitzer held doctorates in this
the stratosphere 4x 25.0% stumper $700 avg J:2 DJ:2
J $400 2022 The troposphere is sandwiched between the earth & this next layer of the atmosphere
DJ $600 1992 To avoid storms in the troposphere, pilots often fly in this next layer of the atmosphere
J $1,000 2022 Some 25 miles in depth, it lies between the troposphere & the mesosphere
refraction 4x $1,200 avg DJ:4
DJ $400 2002 This bending of light as it passes from air into water results from its slower speed
DJ $800 1990 It is this phenomenon which causes white light to break into colors in a prism
DJ $1,600 2023 The ratio of the velocity of light in one medium to its velocity in another is called the index of this
optics 4x $1,100 avg J:1 DJ:3
DJ $600 1993 It's the branch of physics that deals with light & vision
J $1,000 2017 In 1704 Newton published a groundbreaking treatise on this science of light
DJ $800 1997 It's the branch of physics that deals with light & vision
neutrinos 4x 25.0% stumper $1,300 avg J:2 DJ:2
J $1,000 2024 The "Top 10 Erroneous Results" from Science News include a 2011 finding that these chargeless particles can outrace light
J $1,000 2018 First predicted in 1930, this particle with no charge goes through miles of matter without reacting with a proton or neutron
DJ $1,200 2021 Discovered in 1956, this subatomic particle with no charge & very little mass is part of a family of particles called leptons
neon 4x $3,550 avg DJ:4
DJ $200 1985 When excited, this gas glows red, which means our Jeopardy! sign gets excited often
DJ $800 2021 Rare on Earth except in signs, this gas with atomic number 10 is a top 10 element in abundance in the universe
DJ $3,200 DD 2011 The name of this noble gas is from the Greek for "new"
microwaves 4x $525 avg J:1 DJ:3
J $100 1990 These waves transmit TV programs & cook food too
DJ $1,200 2024 On the electromagnetic spectrum, these waves come between radio & infrared & can be as small as 1 mm in length
DJ $400 2021 When used in ovens, these electromagnetic waves operate at about 2,450 megahertz
melanin 4x 25.0% stumper $725 avg J:3 DJ:1
J $100 1991 This dark pigment is produced by skin cells called melanocytes
J $800 2021 The color of the iris comes from this brownish-black pigment—the more there is, the darker the iris' color
J $1,000 2007 Want a safe & long-lasting tan? It may be possible with an implant that triggers production of this skin pigment
mass 4x 25.0% stumper $950 avg J:1 DJ:3
J $200 2011 Technically, the measure of a body's inertia is known as this property of matter
DJ $1,200 2017 The Higgs boson is what endows all elementary subatomic particles with this fundamental property of matter
DJ $400 2021 "m" represents this in Einstein's equation E=mc 2
Marie Curie 4x $600 avg DJ:2 FJ:2
DJ $400 1996 In 1914 she became head of the Paris Institute of Radium
DJ $800 2016 In 1929 President Herbert Hoover presented her with a $50,000 check to buy a gram of radium for a Warsaw lab
FJ 2024 nobelprize.org says some papers of this scientist "are stored in lead boxes", a "legacy that is literally untouchable"
magnesium 4x 25.0% stumper $900 avg J:1 DJ:3
DJ $400 2017 This element, Mg, can be used in underwater flares because it can pull oxygen from the water when combusting
DJ $800 2007 This element, symbol Mg, occurs naturally in such minerals as dolomite & brucite
DJ $2,000 2024 No. 12 on the periodic table, it's the third-most plentiful structural metal in the world after aluminum & iron
Linus Pauling 4x 50.0% stumper $1,575 avg J:1 DJ:3
DJ $1,000 DD 2015 He didn't carry a blue security blanket when he won a Chemistry Nobel for research on the nature of chemical bonds
DJ $1,600 2024 In 1948 this vitamin C advocate found that the polypeptide chain would coil into a structure he called the alpha helix
J $1,700 DD 1997 In the 1940s this Nobel Prize winner & vitamin C advocate studied the structure of antibodies
hydrogen peroxide 4x 25.0% stumper $775 avg J:2 DJ:2
J $300 1991 You can use this compound. H 2 O 2, as a disinfectant or to bleach your hair
DJ $2,000 2021 In addition to its acidity, one reason honey doesn't spoil is that an enzyme in bees helps produce this compound, H 2 O 2, a germicide
J $400 1987 Oxide commonly used on scraped knees & dark roots
graphite 4x $1,300 avg J:1 DJ:3
J $400 1991 To make pencil lead, this form of carbon is mixed with clay
DJ $800 2012 The 1st controlled nuclear reaction was produced in 1942 by using uranium & uranium oxide embedded in this soft carbon
DJ $1,000 1989 This form of carbon can be used as a lubricant or to write out an order to buy it
geothermal 4x $1,350 avg DJ:4
DJ $600 1993 Geysers & volcanos are sources of this type of energy that emanates from deep within the Earth
DJ $2,000 2021 Iceland is a leader in the generation of this type of renewable energy, from words meaning "earth" & "heat"
DJ $800 2024 Most houses in Iceland are heated with this type of energy whose name comes partly from the Greek for "earth"
enzymes 4x 25.0% stumper $875 avg J:4
J $400 2024 1833: Anselme Payen discovers diastase, aka amylase, the first of these proteins that catalyze chemical reactions
J $800 2022 These are proteins, such as hydrolase, that catalyze biochemical reactions
J $1,500 DD 1992 Proteins such as pepsin & rennin that act as catalysts in the body are termed these
entropy 4x 66.7% stumper $1,400 avg J:1 DJ:2 FJ:1
J $600 2017 In 1865 physicist Rudolf Clausius coined this term for the measure of disorder or randomness in a closed system
DJ $1,600 2023 German physicist Rudolf Clausius put in the work by introducing this term for the measure of molecular disorder in a system
FJ 2021 This word used to denote an irreversible dispersion of energy was coined in the 1860s to sound a bit like "energy"
dry ice 4x $325 avg J:1 DJ:3
J $100 1999 Solid water is ice; solid carbon dioxide has this 2-word name
DJ $600 1990 Solid carbon dioxide
DJ $200 1994 At -109 F°., solid carbon dioxide is more commonly called this
deuterium 4x 25.0% stumper $1,025 avg J:2 DJ:2
J $500 1994 Harold Urey won a 1934 Nobel Prize for his discovery of this isotope, also called heavy hydrogen
DJ $1,000 DD 1997 Hydrogen has 3 isotopes: protium, tritium & this one with a mass number of 2
J $600 2007 ( Kelly of the Clue Crew delivers the clue from the lab.) Normally, an ice cube floats; this one, however, sinks right to the bottom because it's made of heavy water, or D 2 O; the D standing for this isotope
copper 4x 50.0% stumper $550 avg J:2 DJ:2
J $100 1991 Used for coins, cupronickel is an alloy of this & nickel
J $500 1985 Sterling silver is not pure silver but an alloy of silver and this metal
DJ $1,200 2008 This reddish metal is a main ingredient of both brass & bronze
Copernicus 4x 33.3% stumper $1,067 avg DJ:3 FJ:1
DJ $400 2005 This Pole died in 1543, days after receiving the first copy of his book "On the Revolutions of Heavenly Bodies"
DJ $800 2018 Cn is the symbol for an artificially produced radioactive element named for this astronomer
DJ $2,000 DD 2019 In 1543 the world revolved around this man who wrote "On the Revolutions of the Heavenly Spheres"
cloning 4x $600 avg J:2 DJ:1 FJ:1
DJ $200 1991 In vertebrates, it's the process of reproducing an entire organism from a single cell
J $600 2007 Scientists in Australia hope to resurrect the extinct Tasmanian tiger by using genetic fragments & this method
J $1,000 2017 Asexual reproduction, a cell duplicating itself, is nature's version of this controversial practice
calcium carbonate 4x 25.0% stumper $975 avg J:1 DJ:3
J $300 1992 Chalk & limestone are naturally occurring forms of this compound, CaCO 3
DJ $800 1990 CaCO 3, it's the main ingredient in limestone
DJ $1,200 2023 This 2-word compound is the main component of both limestone & coral reefs
blue 4x $675 avg J:2 DJ:2
J $200 2003 The primary colors are red, yellow & this
J $500 1992 Cyanosis, a condition where oxygen in the blood is low, turns the skin this color
DJ $1,600 2021 When dipped in a solution with pH above 8.3. litmus paper turns this color
atoms 4x $550 avg J:2 DJ:2
J $200 1985 A 5th C. B.C. Greek philosopher was 1st to theorize that all matter is made of these
J $800 2012 ( Kelly of the Clue Crew shows us molecular models in the lab.) We're using models of ethanol to show the 2 basic types of molecular models; 1 clarifies the bonds between these particles, while the other shows better what the molecule looks like in a...
DJ $400 1991 About 400 B.C. Democritus wrote that matter is made of tiny bits of material he called these
aluminum 4x 25.0% stumper $400 avg J:2 DJ:2
DJ $200 1991 While it makes up more of the earth's crust than iron, its ore, bauxite, is rarer than iron ore
J $500 1998 To produce this metal using the Bayer Process, you begin with caustic soda & bauxite
DJ $400 1986 The oxide of this common lightweight metal forms rubies & sapphires
a molecule 4x $400 avg J:2 DJ:2
J $400 2011 O 2 is a diatomic one of these units of a pure substance; H 2 O is polyatomic
DJ $400 2009 ( Sarah of the Clue Crew holds up a sugar cube.) At sea level, at 32 degrees Fahrenheit, 1 cubic centimeter of air, the size of a sugar cube, contains 45 billion billion of these, from the Latin for "little mass"
DJ $400 1994 It's the smallest particle of a compound that has the properties of the compound
(Ivan) Pavlov 4x $600 avg J:1 DJ:3
DJ $400 2013 By ringing a bell, this Russian physiologist made dogs drool even if they couldn't see food
J $600 2005 The director of St. Petersburg's Institute of Experimental Medicine until his 1936 death; his name ring a bell?
DJ $600 1995 At the Institute of Experimental Medicine, he studied apes as well as salivating dogs
The Human Genome Project 4x $1,533 avg DJ:3 FJ:1
DJ $1,600 2024 Completed in 2003, this effort of mapping 3 billion base pairs of DNA in Homo sapiens cost about $2.7 billion
FJ 2000 Made available for download in July 2000 by UCSC, the 739MB file of this "Project" consists of As, Ts, Gs & Cs
DJ $1,000 2000 This mapping project begun in 1990 is less than 50% done, though a private firm, Celera, claims to have 90% finished
solar energy 4x $850 avg DJ:4
DJ $400 2016 The Department of Energy says homes employing this water heating method can save 50% on their bills
DJ $800 1993 Matter has the "potential" form of this by virtue of its position or structure
DJ $1,000 1985 Mirrors & photovoltaic cells are among the devices used to collect this
Worth Knowing (144)
zinc 3 time 3 the Nuclear Regulatory Commission 3 the lanthanides 3 the Doppler effect 3 Tesla 3 temperature 3 teeth 3 smell 3 rust 3 rocks 3 radioactivity 3 quarks 3 Quantum 3 protein 3 pasteurization 3 parapsychology 3 Paleozoic 3 ozone 3 osmosis 3 ornithology 3 order 3 Oppenheimer 3 neurons 3 momentum 3 microwave 3 metamorphosis 3 Meiosis 3 Linnaeus 3 lactic acid 3 ionization 3 insulin 3 Half-life 3 green 3 gold 3 glass 3 France 3 evolution 3 electrolytes 3 covalent 3 cosmology 3 calcium 3 buoyancy 3 bonds 3 birds 3 atomic number 3 amino acids 3 Alfred Nobel 3 acoustics 3 a seismograph 3 a Petri dish 3 a cell 3 a caldera 3 a battery 3 zirconium 2 yogurt 2 yellow 2 volt 2 Vaporization 2 up 2 turbulence 2 trees 2 transfer 2 torque 2 TNT 2 thrust 2 Thomas Edison 2 the weather 2 the uncertainty principle 2 the periodic table 2 the Large Hadron Collider 2 The Island of Dr. Moreau 2 the fallopian tubes 2 the epicenter 2 the dew point 2 surface tension 2 string theory 2 spontaneous 2 smelling salts 2 sleet 2 silicon 2 roentgen 2 Robert Boyle 2 RNA 2 ribonucleic acid 2 reaction 2 radon 2 precipitation 2 platinum 2 pitchblende 2 physiology 2 phylum 2 phosphorus 2 pharmacology 2 pH 2 penology 2 nucleotides 2 nitrous oxide 2 nitric acid 2 nickel 2 Neutral 2 nerves 2 mutations 2 molecules 2 mole 2 mimicry 2 Michael Faraday 2 metric system 2 metals 2 Mendel 2 manganese 2 magnetic 2 Lymphocytes 2 leukemia 2 lemmings 2 Lavoisier 2 lava 2 krypton 2 kinetic energy 2 Joseph Priestley 2 isotope 2 iridium 2 invertebrates 2 hydroelectric power 2 hydrochloric acid 2 hemophilia 2 hemoglobin 2 Heart 2 gasoline 2 gamma rays 2 Fortran 2 formaldehyde 2 eyes 2 Extinction 2 evaporation 2 equilibrium 2 entomology 2 elements 2 electrolyte 2 electrolysis 2 eczema 2 economics 2 ductile 2 drag 2

Astronomy / Space

94 answers | 501 clues
Must-Know (16)
hydrogen 23x $604 avg J:11 DJ:12
J $100 1993 It's the element whose atomic weight is closest to its atomic number
J $500 1987 The name for this gas comes from the French for "water former"
DJ $1,200 2016 Fuel cells made of this most abundant element in the galaxy powered the Space Shuttles
gravity 21x $440 avg J:10 DJ:10 FJ:1
J $100 1996 g. Acceleration due to this, varies slightly with latitude since the Earth is not a perfect sphere
J $500 1991 Geotropism is the response of living things to the effects of this force
J $1,000 2007 At the Earth's surface, this force produces acceleration of about 32 feet per second per second
Galileo 18x 5.6% stumper $567 avg J:5 DJ:13
J $200 2015 ( Jimmy of the Clue Crew, at Harvard University's Historical Scientific Instruments, holds a metal right angle with a plumb bob.) One instrument, a geometrical & military compass, was used to find areas & volumes, & even determined how best to load &...
DJ $600 1995 Around 1590 he formulated the law of falling bodies, s=1/2gt squared
DJ $1,200 2024 This Italian scientist's legendary falling bodies experiment showed falling objects accelerate at the same rate
carbon 18x 22.2% stumper $856 avg J:7 DJ:11
J $100 1998 By definition, organic compounds must contain atoms of this element
DJ $600 1991 The black charred surface on your toast this morning is this element
J $1,000 DD 2003 This element's name is from the Latin for "charcoal"
Jupiter 15x 6.7% stumper $1,345 avg J:8 DJ:7
J $100 1996 You could put all the other planets inside this planet & still have room to spare
J $500 1986 Heinrich Schwabe not only studied sunspots, but discovered the "Great Red Spot" on this planet too
DJ $1,000 DD 2019 Named for the man who first observed them, the "Galilean satellites" are the 4 largest moons of this planet
carbon dioxide 15x 13.3% stumper $333 avg J:9 DJ:6
J $100 1993 In breathing it's the gas you expel to the atmosphere
J $600 2008 ( Cheryl of the Clue Crew performs a science experiment.) By mixing baking soda, a chemical base, with the acid in the lime juice, this gas is produced, resulting in a bubbly liquid
J $200 2026 Dry ice is what we commonly call the solid form of this gas
the Sun 14x 7.1% stumper $314 avg J:7 DJ:7
J $100 2001 Heliology is the study of light from this source
DJ $800 1985 A heliologist can really get burned by studying this
DJ $1,200 2009 Usually seen daily by most people, it produces 3.83 x 10 26 watts of power in the form of light
Saturn 13x 7.7% stumper $754 avg J:5 DJ:8
DJ $200 1997 In 1857 James Clerk Maxwell concluded that its rings were made of small, unconnected particles
J $1,000 2019 This planet is less dense than water—but it's still 95 times the mass of the Earth
DJ $200 1990 In 1675, Italian astronomer Gian Domenico Cassini discovered a dark gap in this planet's main ring
Water 12x 8.3% stumper $375 avg J:5 DJ:7
J $100 2001 The Earth is the only planet in our solar system to have 2/3 of its surface covered by this
DJ $600 1987 Hydrates are defined as compounds containing molecules of this
J $100 1993 A hydrate contains this compound weakly bound in its crystals
Mercury 12x 25.0% stumper $892 avg J:4 DJ:8
DJ $200 1997 From the surface of this innermost planet, the sun appears 2.5 times as large as it does from Earth
J $500 1999 A millimeter of this element is a common unit for measuring pressure, including blood pressure
DJ $1,000 1993 Estimated temperatures on this planet range from 950° F. on the sunlit side to -346° on the dark side
Mars 11x 9.1% stumper $391 avg J:6 DJ:5
DJ $200 2001 This planet, once wrongly thought to have canals, may have water at its surface after all
J $1,000 DD 2002 In the 1780s William Herschel determined its axial inclination & found it had ice caps
DJ $200 1987 Studying this planet in 1877, Schiaparelli called the lines he saw "canali" meaning "channels"
the electron 11x 9.1% stumper $564 avg J:6 DJ:5
J $200 1990 Negatively charged, it was the 1st subatomic particle discovered
DJ $800 2013 Physicist J.J. Thomson discovered this subatomic particle in 1897
DJ $1,200 2009 Negative particle (8)
igneous 10x 10.0% stumper $820 avg J:4 DJ:6
J $200 1993 Of the 3 main classes of rock, this one is further divided into plutonic & volcanic types
DJ $600 1990 This class of rocks formed by the solidification of molten rock includes basalt & granite
DJ $1,200 2008 Of the 3 main classes of rock, this one is further divided into plutonic & volcanic types
Uranium 9x 22.2% stumper $833 avg J:4 DJ:5
DJ $200 1985 Heaviest element found in nature, named for a planet
J $500 2001 In 1911 Arthur Holmes used the decay of this element to lead to measure the age of the Earth
DJ $1,600 2024 The Encyclopedia Britannica calls it the most important of the actinoids
helium 9x 37.5% stumper $538 avg J:2 DJ:6 FJ:1
DJ $400 DD 2015 The exosphere, the edge of the atmosphere, is primarily made of particles of hydrogen & this element
J $500 1996 It has the lowest boiling point of any element, -452 degrees Fahrenheit
FJ 1985 From name of Greek sun god, it is the 2nd most abundant element in the universe
iron 8x 12.5% stumper $662 avg J:4 DJ:4
J $100 1995 Ferrovanadium is an alloy of vanadium & this metal
J $1,000 2004 Scientists figure Mars isn't creme-filled, but has a liquid core made of this
DJ $200 1987 After aluminum, it's the 2nd most abundant metal in the earth's crust
Should-Know (35)
photosynthesis 7x $571 avg J:1 DJ:6
DJ $200 1992 Structures called chloroplasts are the main sites for this process in green plants
DJ $600 2001 Oceanic bacteria may convert sunlight to energy with this process, like plants
DJ $1,200 2011 A variety of Atlantic sea slug eats algae, retains some of it & can then undergo this plant process
inertia 7x 14.3% stumper $1,514 avg J:4 DJ:3
J $400 2016 A long pole helps a tightrope walker by increasing this tendency of a body to stay at rest
DJ $600 1991 It's the tendency of a body to resist a change in its state of motion
DJ $3,000 DD 2018 Newton's 1st Law of Motion, known as the Law of this, is why a car crash throws you into the windshield—buckle up!
Venus 6x $800 avg J:4 DJ:2
J $300 1996 After the sun & moon, this planet is the brightest object in the sky
DJ $800 2024 Radar images taken by the Magellan spacecraft in the 1990s helped determine that this planet has around 85,000 volcanoes
J $1,000 2004 Brighter in the night sky than any star is this planet that comes closest to the Earth
Uranus 6x 16.7% stumper $667 avg J:3 DJ:3
J $400 2015 ( Sarah of the Clue Crew, at Harvard University's Historical Scientific Instruments, shows an enclosed clockwork model.) Clockmaker Joseph Pope was about halfway through his 12-year project of building a gear-driven model of the Solar System that sho...
DJ $600 1986 The 7th planet, which was 1st named the "Georgian Star" in honor of Britain's reigning monarch
DJ $1,000 1992 William Herschel earned a pension from King George III after discovering this planet in 1781
Ultraviolet 6x 16.7% stumper $533 avg J:3 DJ:3
J $100 1999 In weather forecasting, the UV index refers to the intensity of this type of radiation
DJ $2,000 DD 2013 Defined as 10-400 nanometers on the spectrum, these rays fall between visible light & X-rays
J $100 1996 Germicidal lamps emit these rays
the Big Bang 6x $620 avg J:1 DJ:4 FJ:1
J $300 1986 The Hubble constant tells how fast the universe is expanding since this "noisy" event occurred
DJ $1,600 2018 Gravity became its own force during the rather brief grand unification era, from 10 -43 to 10 -35 seconds after this
FJ 2005 Sky & Telescope magazine's contest to replace this term for a single event got 13,000 entries, but chose none
plasma 6x $783 avg J:2 DJ:4
J $300 1988 It's the clear, almost colorless, liquid part of the blood, or the highly ionized "4th state" of matter
DJ $1,200 2023 The phenomenon of St. Elmo's fire familiar to sailors & aviators is a luminous glow of this 4th state of matter
J $400 2017 This liquid straw-colored part of blood consists of about 90% water
Nitrogen 6x $700 avg J:1 DJ:5
J $400 1992 Ammonia, widely used as a refrigerant & cleaner, is composed of hydrogen & this element
DJ $600 1997 All amino acids contain carbon, hydrogen, oxygen & this element
DJ $1,200 2016 The New Horizons probe showed glaciers on Pluto made of this element that's 4/5 of Earth's atmosphere
methane 6x $1,033 avg J:2 DJ:4
J $600 2015 CH 4, it's the chief constituent of natural gas
DJ $1,000 1985 The main part of natural gas, it's sometimes called marsh gas or firedamp
DJ $600 2001 ( Sofia of the Clue Crew reports from the La Brea Tar Pits in Los Angeles.) The bubbling seen here is caused by this gas, a major part of Jupiter's atmosphere
black holes 6x 60.0% stumper $1,200 avg J:2 DJ:3 FJ:1
J $600 2020 In 2017 scientists recorded ripples in space-time called gravitational waves, which emerged when 2 of these collided
J $1,000 2016 In 2015 astronomers found 2 giant ones orbiting each other at the center of a nearby quasar
FJ 2024 Physicist John Wheeler said he coined this term as a faster way to say "completely collapsed objects"
a comet 6x $533 avg J:1 DJ:5
J $400 2021 C/1847 T1 is the formal name of one of these astronomical objects
DJ $800 2019 A coma is the hazy atmosphere of gases that forms around one of these as it nears the sun
DJ $400 2016 Ison, one of these space travelers, was called a "sungrazer", passing within 684,000 miles of the surface
3 6x 16.7% stumper $617 avg J:2 DJ:4
J $300 1987 Copernicus placed the sun in the center of the universe & the Earth this many planets out
DJ $600 1987 # of stars in the "belt" of the constellation Orion
DJ $1,200 2020 A Feb. 1953 paper by Linus Pauling says the structure of DNA involves this many "intertwined helical polynucleotide chains"—so close
the solar wind 6x 16.7% stumper $1,567 avg J:1 DJ:5
J $200 2000 Ventifacts are rocks that are shaped by sand driven by this force of nature
DJ $800 2016 100-foot-tall towers grouped in "farms" are used to create this type of power
DJ $1,200 2022 In 2020 the U.S. added more energy capacity from this type of power than any other, with plans for more offshore
the Moon 6x 16.7% stumper $367 avg J:2 DJ:4
J $300 1997 Around 1840 chemist John William Draper took the first photograph of this heavenly body
DJ $800 2015 Gagarin Crater
J $300 1996 The Apennines, which border the Mare Imbrium, are this satellite's most conspicuous mountain range
the core 5x $680 avg DJ:5
DJ $400 2010 The part of a pear with the seeds
DJ $600 1996 The sun's energy is produced in this central region
DJ $1,200 2025 Dynamo theory says that movement of liquid iron in this part of the Earth creates the planet's magnetic field
Starch 5x 20.0% stumper $740 avg J:2 DJ:3
J $300 2001 Before their energy can be released, molecules of this in potatoes must be broken down into sugars
J $600 2020 ( Sarah of the Clue Crew shows high-speed photography of a popcorn kernel popping on the monitor.) Pressure of about 135 pounds per square inch is needed to pop each popcorn kernel; the pressure comes from steam, created when this white carbohydrate ...
DJ $1,200 2004 Gerty Theresa Cori won a Nobel Prize for finding an enzyme that helps the body turn this into sugar
Pluto 5x 20.0% stumper $700 avg J:1 DJ:4
J $100 1997 This ninth planet's unusual orbit sometimes brings it closer to the sun than the eighth planet
DJ $600 1985 In 1930, 24-year-old astronomer Clyde Tombaugh discovered it
DJ $1,200 2003 In 2002 an 800-mile-diameter planetoid called Quaoar was found 1 billion miles past this 1430-mile-diameter planet
paleontology 5x $1,040 avg J:3 DJ:2
J $400 2001 From the Greek meaning "study of ancient existence", it's the study of prehistoric plants & animals from fossil remains
DJ $600 1994 O.C. Marsh, a discoverer of Pterodactyl fossils, became the USA's first professor of this science in 1866
J $1,000 2007 The study of fossils, as from a T-rex
milk 5x $380 avg J:3 DJ:2
J $100 1987 In the platypus, this is secreted through pores in the mother's abdomen & lapped up by the young
J $500 1988 Casein, the main protein in this liquid, is used to make buttons
DJ $200 1993 In 1780 Carl Scheele isolated lactic acid in this substance that had soured
escape velocity 5x $1,320 avg DJ:5
DJ $1,000 1996 For a spaceship to leave the Earth's gravitational field, it's 11.2 kilometers per second
DJ $1,200 2025 It does take a rocket scientist to calculate this minimum speed required to break free from a planet's gravity
DJ $1,200 2016 (Sarah of the Clue Crew drops an egg and it goes "splat".) To calculate the speed of a falling egg from a resting position, use V = G x T, where T is time, G is the acceleration of gravity, measured at 32 feet per second squared, & V stands for this
The Martian Chronicles 4x 25.0% stumper $700 avg J:2 DJ:2
J $200 2017 Published in 1950, these Ray Bradbury "Chronicles" begin in 1999, when men leave Earth to colonize a nearby planet
DJ $800 2016 "Chroniques martiennes"
J $1,000 2009 This Ray Bradbury collection of linked short stories includes "The Earth Men" & "The Moon Be Still As Bright"
Stephen Hawking 4x $1,450 avg DJ:4
DJ $600 1997 In 1993 he made a "brief" appearance as himself on an episode of "Star Trek: The Next Generation"
DJ $1,600 2026 The radiation named for this man is theoretically emitted by the space-time around a black hole
DJ $1,600 2002 During the 1970s this British physicist made the unexpected discovery that black holes emit thermal radiation
Sputnik 4x $625 avg J:2 DJ:2
DJ $200 1995 K. Tsiolkovsky, who predicted space travel, would have been 100 when this was launched in October 1957
DJ $1,600 2008 The Space Age began in 1957 when Russia launched this satellite
J $300 2000 Alfred Lovell's Jodrell Bank radio telescope was finished in 1957 just in time to track this 1st artificial satellite
Sirius 4x 50.0% stumper $1,300 avg DJ:4
DJ $1,000 1997 The name of this dog star, the brightest star in the night sky, is Greek for "scorching"
DJ $1,000 1996 The small companion to this "Dog Star" was the first star identified as a white dwarf
DJ $1,600 2026 Canopus is the second-brightest star in the night sky; this one is first
Neptune 4x 50.0% stumper $850 avg J:1 DJ:3
DJ $200 1990 The fourth largest planet in our solar system, it's usually next to last from the sun
DJ $800 2006 Geysers of what is probably nitrogen rise as high as 5 miles on Triton, this planet's largest moon
DJ $2,000 2004 In the 1940s Gerard Kuiper discovered Miranda, a moon of Uranus & Nereid, a moon of this planet
infrared 4x 25.0% stumper $875 avg J:2 DJ:2
J $300 1993 The IRAS telescope, which discovered 5 comets, made its observations in this spectrum of light
DJ $800 1985 Night-sight gun scopes measure heat radiation in this range
DJ $2,000 2021 The so-called whitest paint has been created to help combat global warming by radiating this "colorful" band of the spectrum
Hubble 4x 25.0% stumper $1,700 avg J:1 DJ:3
J $300 1991 Though its mirror is flawed, this $1.5 billion space telescope is producing useful data
DJ $500 DD 2005 The ratio of the speed of galaxies to their distance from Earth is the "constant" named for this astronomer
DJ $2,000 2020 The expansion rate of the universe is the constant named for this man, who in the 1920s pegged it at 7 times the current estimate
Halley's Comet 4x 33.3% stumper $1,067 avg J:1 DJ:2 FJ:1
J $400 1996 When astronomers got a close-up look at this object in 1985-86, its nucleus looked like a big potato
DJ $1,200 DD 1996 Bruce Morton & Francis Reddy wrote books on it in 1985; we'll probably see more books on it in 2061
FJ 2023 A craft that visited it was named for Giotto, based on the story that 680 years earlier, the painter depicted it as the Star of Bethlehem
Fahrenheit 4x $550 avg DJ:4
DJ $400 2018 In the 1700s he developed the first practical mercury thermometer & the temperature scale that bears his name
DJ $600 1987 German-Dutch instrument maker who came up with a glass thermometer filled with mercury
DJ $400 2004 This thermometer developer discovered that the boiling point of a liquid varies with atmospheric pressure
clouds 4x $200 avg J:2 DJ:2
J $100 1996 Fractus, congestus & humilis are terms used to describe these aerial formations
J $100 1993 Nephology is the branch of meteorology that studies these, nimbus or otherwise
DJ $200 1997 In 1803 Luke Howard coined names for types of them, including cumulus & stratus
astrology 4x 25.0% stumper $325 avg J:3 DJ:1
J $100 1992 It deals with the influence of the stars & planets on a person's life
J $600 2003 In 1585 Pope Sixtus V condemned the practice of this; wonder if anyone saw that coming?
J $200 1996 This study of the supposed effect of the stars on human life could be called zodiacology
4 4x $800 avg DJ:4
DJ $200 1989 In his relativity theory, Einstein proposed a space-time continuum made up of this many dimensions
DJ $600 1989 The number of planets in our solar system larger than the Earth
DJ $2,000 2021 In a molecule of sulfuric acid, there are this many atoms of oxygen
2 4x 25.0% stumper $225 avg J:2 DJ:2
J $100 1989 A little harder than talc, but not as hard as calcite, gypsum is this number on the Mohs scale
DJ $200 2001 The only even prime number
J $200 1988 Minimum number of lenses you need to make a simple refracting telescope
the Earth 4x $425 avg J:2 DJ:2
J $100 1992 The mean distance of this planet from the Sun is one astronomical unit
DJ $800 1995 Geodesy is a scientific branch concerned with the exact shape & size of this
J $400 2003 Traveling 1 astronomical unit from the Sun, you should just reach this planet
Piltdown Man 4x $967 avg J:1 DJ:2 FJ:1
J $100 1986 The only animal that has walked on the moon
DJ $800 1985 Discovery of this "ancient man" in England proved to be a hoax
DJ $2,000 2009 No one knows who planted this fossilized "man" in an English dig, setting the study of evolution back decades
Worth Knowing (43)

Biology / Animals

58 answers | 160 clues
Must-Know (2)
anthropology 8x 12.5% stumper $1,700 avg J:5 DJ:3
J $200 2023 Physical & cultural are branches of this "study of humans"
DJ $600 1996 Franz Boas & Margaret Mead were experts in this field
DJ $1,600 2024 At Brown Jessaca Leinaweaver, the chair of this department aims to study "humanity, past & present"
amber 8x 12.5% stumper $712 avg J:5 DJ:3
J $100 1997 This fossilized resin from prehistoric pines can preserve an insect forever
J $500 1987 Term for the fossilized resin from prehistoric pines
J $1,000 2005 William Gilbert coined the word electricity, which comes from the Latin word for this fossil resin
Should-Know (7)
photons 5x 20.0% stumper $780 avg J:2 DJ:3
J $500 1992 American Arthur Compton's work proved the existence of these "particles" of light
DJ $1,000 1996 Quantum optics is the branch of optics that deals with these particles of light
J $600 2024 The hypothetical solar sail on a spaceship wouldn't fly on solar wind, as you might think, but on these particles, also known as light quanta
bees 5x $360 avg J:2 DJ:3
J $200 2004 Buzz in if you know that apiology is the study of these
DJ $400 2024 Karl von Frisch painted these insects to track their movements & show how they twerk their way to pollen
DJ $400 2010 Karl von Frisch won a Nobel Prize for work on animal behavior patterns, largely using the "dance' of this insect
yeast 4x $550 avg J:2 DJ:2
DJ $400 2024 Fundamental discoveries about how cancer cells proliferate came from study of the baker's type of this organism
DJ $1,000 1992 The enzyme zymase allows these one-celled organisms to convert sugar into alcohol & CO 2
J $400 2006 ( Jon of the Clue Crew reports from Copenhagen, Denmark.) In 1883, Carlsberg developed Saccharomyces carlsbergensis, a special strain of this to ferment the sugars in beer
Max Planck 4x 25.0% stumper $1,250 avg DJ:4
DJ $800 2001 In 1930 this originator of the quantum theory became president of the scientific society later renamed for him
DJ $1,000 1991 In 1900 this German physicist put forth his Quantum Theory
DJ $1,200 2025 The "Max" smart scientists at this institute in Cologne finished sequencing the domestic potato genome
Luther Burbank 4x 66.7% stumper $300 avg J:2 DJ:1 FJ:1
J $200 1997 In 1875 this plant breeder moved to California using profits earned on his potato
J $500 DD 2004 In the 1930s this California transplant posthumously received plant patents No. 12-16
FJ 1992 In 1927, a year after his death, his autobiography "Harvest of the Years" was published
genetics 4x $350 avg J:3 DJ:1
J $100 1993 This branch of biology deals with the principles of heredity
J $500 1988 It's the branch of biology dealing with heredity
DJ $400 2019 Gregor Mendel is referred to as the father of this field, the science of heredity
the eye 4x $350 avg J:3 DJ:1
J $200 1997 Used to control glaucoma, a trabeculectomy is a procedure that reduces pressure in this organ
DJ $800 2022 The epicanthus is a fold of skin at the inner corner of this part of the human body
J $300 2000 Pre-Y1K scientists figured this organ gave out light; they were, of course, wrong
Worth Knowing (49)

Other

33 answers | 82 clues
Should-Know (3)
Psychology 7x 16.7% stumper $933 avg J:2 DJ:4 FJ:1
J $400 2019 A 2016 web article for the magazine this -ology Today addressed the "Is it a science?" debate & said yes
DJ $2,000 2024 William James' 1890 "The Principles of" this is considered a classic in the field
FJ 2001 In 1908 Hermann Ebbinghaus said this field "has a long past, but only a short history"
Frank Herbert 4x 25.0% stumper $900 avg DJ:4
DJ $800 2007 He wrote 5 sequels to "Dune", including "Dune Messiah" & "Children of Dune"
DJ $1,000 DD 2019 As well as playing in the "Dune"s, this sci-fi author penned "The White Plague", about a mad scientist's quest for revenge
DJ $800 1992 "Children of Dune" was his extremely successful sequel to "Dune" & "Dune Messiah"
the ohm 4x $650 avg J:2 DJ:2
J $300 1994 The Greek letter omega is used as the symbol for this unit of electrical resistance
J $500 1998 Ir"resistable" German physicist with a law about the flow of an electric current
DJ $1,000 1990 This unit of electrical resistance was named for a German physicist
Worth Knowing (30)

Math / Physics

20 answers | 54 clues
Should-Know (3)
lightning 5x $580 avg J:3 DJ:2
DJ $200 1992 Pilots have reported seeing a rare form of this which strikes upward from a cloud rather than down
DJ $2,000 2016 Chinese scientists captured the first video & spectrum of the elusive ball type of this atmospheric phenomenon
J $200 1988 This discharge can be produced in snowstorms, sandstorms & volcanic clouds as well as thunderstorms
a lever 5x $240 avg J:2 DJ:3
J $100 1996 This rigid beam pivoted at a fulcrum is the simplest of simple machines
J $100 1987 One of the simplest machines, it's a rigid beam pivoted at a fulcrum
DJ $200 1988 From Old French "to raise", examples of this include a crowbar, tongs & a seesaw
Marconi 4x 25.0% stumper $1,600 avg J:1 DJ:3
J $500 1987 For his work in radio, this Italian electrical engineer shared the 1909 Nobel Physics Prize
DJ $1,200 2024 "Thunderstruck" tells the interwoven stories of murderer Hawley Crippen & this wireless inventor
DJ $1,200 2004 For helping to develop "wireless telegraphy" he & Karl Braun shared the 1909 Nobel Prize in Physics
Worth Knowing (17)

Earth Science

15 answers | 44 clues
Should-Know (3)
seismology 7x 14.3% stumper $529 avg J:1 DJ:6
J $300 1986 While this study tries to predict when earthquakes will occur, it's still on shaky ground
DJ $600 1991 It's the science that deals with earthquakes & related phenomena
DJ $1,200 2021 Charles Richter taught this -ology at Caltech from 1937 to 1970
meteorology 7x $300 avg J:3 DJ:4
J $100 2000 Though it sounds like it deals with space matter, it's the study of weather
DJ $800 2013 This -ology practiced by a guy on the 6 o'clock news sounds like it's about bodies falling from space
J $200 2021 Atmospheric sciences include climatology & this, the study & forecasting of the weather
magma 4x $700 avg J:1 DJ:3
DJ $400 2021 The mafic type of this 5-letter underground molten rock can reach more than 2,000 degrees Fahrenheit
DJ $800 2022 Igneous rocks are formed after this 5-letter type of molten rock cools
DJ $1,200 2015 The water in most hot springs is heated by this 5-letter substance
Worth Knowing (12)

Medicine / Health

12 answers | 30 clues
Should-Know (2)
the kidney 5x 20.0% stumper $800 avg J:2 DJ:3
J $400 2016 A nephrectomy is the surgical removal of this organ
DJ $800 1992 An expert in nephrology would know a lot about this bodily organ
DJ $2,000 2018 When this organ is embryonic, specialized tubules empty into Wolffian ducts
X-rays 4x $350 avg J:2 DJ:2
J $100 1991 Barium sulfate is used in diagnosing gastrointestinal problems since it's opaque to these rays
DJ $600 1995 Wilhelm Roentgen announced the discovery of these rays in "Eine neue Art von Strahlen" in 1895
J $300 1996 Oh, ya doesn't hafta call 'em Roentgen rays, you can call 'em this
Worth Knowing (10)

Botany / Plants

3 answers | 7 clues
Worth Knowing (3)
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