Back to 161 Science Riddles With Answers

161 Science Riddles With Answers

161 riddles · answers on the last page · riddleup.com/riddles/science-riddles

  1. Where are the most sweat glands located?
  2. How many vertebrae in the human spine?
  3. First vaccine developed for which disease?
  4. How many chambers in the human heart?
  5. What does the gallbladder secrete?
  6. What does DNA stand for?
  7. Average weight of a newborn baby?
  8. How long is the large intestine?
  9. How many taste buds are on the tongue?
  10. How many skin cells shed every minute?
  11. What is the heaviest internal organ?
  12. How many bones are in the human body?
  13. Who created the first polio vaccines?
  14. How much blood is in the human body?
  15. What is the rarest blood type?
  16. What is the largest organ in the human body?
  17. World’s largest Hydroelectric Power Plant?
  18. What is the deepest part of the ocean?
  19. How much does a cubic foot of water weigh?
  20. What is the pH of water?
  21. How much water do Americans use daily?
  22. How long can a human live without water?
  23. How often is the air's water replenished?
  24. What provides 90% of atmospheric water?
  25. How much of Earth’s water is saltwater?
  26. Where is most freshwater located?
  27. How much water is stored in oceans?
  28. How much of Earth is covered in water?
  29. How many bones are in a giraffe’s neck?
  30. What is the smallest mammal on Earth?
  31. What animal has the longest lifespan?
  32. What do you call a female elephant?
  33. What do you call a group of flamingos?
  34. How long can beavers hold their breath?
  35. What are sea monkeys?
  36. What animal kills the most humans each year?
  37. Largest mammal in North America?
  38. Which animal did Australia go to “war” with?
  39. Length of the largest blue whale measured?
  40. Average distance between Earth and the moon?
  41. What planet is closest in size to Earth?
  42. Where does the asteroid belt lie?
  43. Who was the first American woman in space?
  44. How long for the ISS to orbit the Earth?
  45. How long to drive to the nearest star at 70 mph?
  46. How long would it take to walk to the moon?
  47. What is the coldest planet in our solar system?
  48. How many orbits has Neptune made since discovery?
  49. What shape is the moon?
  50. When was our solar system formed?
  51. Which two planets have no moons?
  52. What is the hottest planet in our solar system?
  53. How long for one orbit around the galactic center?
  54. How fast does the solar system orbit the Milky Way?
  55. What color is the sunset on Mars?
  56. How many stars are in the universe?
  57. How long to fly a plane to Pluto?
  58. Atoms with different masses but same element?
  59. Element named after "greenish-yellow"?
  60. Who is the father of modern chemistry?
  61. What element is a diamond composed of?
  62. Particles that make up protons and neutrons?
  63. When was the first Nobel Prize in chemistry awarded?
  64. What is the symbol for iron?
  65. What are helium, neon, and argon called?
  66. When was the modern periodic table introduced?
  67. At what temp are Celsius and Fahrenheit equal?
  68. What is the newest element on the periodic table?
  69. Periodic element named after Albert Einstein?
  70. Most abundant element in the Earth’s crust?
  71. What is hydrogen oxide?
  72. What is a solid changing directly into a gas called?
  73. What scale measures the hardness of minerals?
  74. What is the splitting of atomic nuclei called?
  75. What does a conchologist collect?
  76. What is the red pigment that transports oxygen?
  77. How long is the memory of a goldfish?
  78. Which is the only rock that floats?
  79. How long does sun light take to reach Earth?
  80. What is the largest desert in the world?
  81. What are the most common elements in the human body?
  82. What does a Geiger counter measure?
  83. How many bones do sharks have?
  84. What element did Joseph Priestley discover in 1774?
  85. Are the sun and moon the same size?
  86. Who is credited with the theory of evolution?
  87. What country has the most tornadoes?
  88. What do you call molten rock before it has erupted?
  89. How do you determine the age of a tree?
  90. What element is used to create nuclear energy?
  91. What do you call a volcano that’s not currently erupting?
  92. Which is the most abundant element in the universe?
  93. What is the study of fungi called?
  94. How many colors are in the rainbow?
  95. What do you call the study of weather and atmosphere?
  96. What do you call an animal that eats both plants and animals?
  97. How many elements are on the periodic table?
  98. What are the three layers of the Earth?
  99. What is the fastest animal on land?
  100. What is the largest planet in our solar system?
  101. Next element in: H, Be, F, S, Mn, Kr, In, Gd, Tl?
  102. How many bounces will it take for a ball to stop?
  103. Why did Andrew die after mopping bleach with a rag and fluid?
  104. If you hammer a nail into a tree, where is it 5 years later?
  105. How much more powerful is an earthquake 0.5 higher on the scale?
  106. The beginning of the end, as well as the end of time and space.
  107. I'm sometimes full, but I never overflow.
  108. At night they come without being fetched, by day they are lost.
  109. I make up almost of the universe, but no one knows about me.
  110. I am a god, I am a planet, and I can measure the temperature.
  111. If you give it food, it'll live if you give it water, it will die.
  112. What has a mouth but can't chew?
  113. What goes around the wood but never goes into the wood?
  114. What is neither water nor land but is always soaking wet?
  115. Born in the ocean and white as snow; disappears in water.
  116. What four elements make up something that terrifies criminals?
  117. Benzene ring with iron atoms replacing carbon atoms?
  118. I am a unit of chemical elements, but I can never be trusted. Why?
  119. I come as a gas, and I'm in line with Neon. Home of a Super man.
  120. What number do Nickel and Neon make when they are combined?
  121. Which element is derived from a Norse god?
  122. What do you do with a dead chemist?
  123. Which two elements heal?
  124. Black when you get it, red when you use it, grey when you are finished.
  125. What chemical doesn't like to follow?
  126. What can eat a lot of iron without getting sick?
  127. I am the equivalent of a one-way street in the universe. What am I?
  128. What period of time is the lightest/weighs the least?
  129. Which concept in physics is the loneliest?
  130. What goes up and down without moving?
  131. You can find me in Mercury, Earth, Mars, and Jupiter. But not Neptune or Venus.
  132. You can't see me but I can see you. I can see right through.
  133. It is very hard to create me, but I can't be destroyed. I can only change form.
  134. I can be hot, cold, hard, and go through anything. What am I?
  135. Which is heavier, a ton of feathers or a ton of rocks?
  136. What is the center of gravity?
  137. You can't see me, I can't be touched... but I cook your lunch. What am I?
  138. Lots of people have heard it, but no one has seen it. It will not speak back unless spoken to.
  139. When liquid splashes me, none seeps through; when I am hit, I change color. What am I?
  140. I am a ball that can be rolled, but never bounced or thrown. What am I?
  141. One monkey has a banana, one a stick, one nothing. Which primate is the smartest?
  142. Your mom and dad each gave you 23 of these threadlike strands. What are they?
  143. What grows only upwards and can never come down?
  144. I can be good for you, but I can also be bad for you, and you will find me wherever you go. What am I?
  145. I'm great at tasting but horrible at smelling. What am I?
  146. I love to roam, but I always stay home. If you carried what I carried, you'd end up breaking your back! What am I?
  147. I am under your face and outside your mind. What am I?
  148. I am needed for flight but cannot fly on my own. What am I?
  149. I am hard as a stone but you can find me on your body. What am I?
  150. What can you hold for no longer than a few seconds, even without your hands?
  151. What are 10 things that you can always count on?
  152. I am a gas that is essential for plants but I can't be bought at the gas station. What am I?
  153. Nobody empties me, but I never stay full for long. What am I?
  154. I have no wings, but I can fly. And I have no eyes, but I can cry. What am I?
  155. I have storms that rage for hundreds of years. My winds are the fastest. What am I?
  156. I'm closest to the Sun, but I don't get much attention. What am I?
  157. I'm red all over, with dust in the air. What am I?
  158. I'm your home and the third from the Sun. What am I?
  159. I'm hot and bright, but don't touch! I shoot up from the Earth in a big rush. What am I?
  160. I live in the sky but fall to the ground. I'm cold and white and make no sound. What am I?
  161. I'm not alive, but I can grow. I don't have lungs, but I need air. What am I?

Answers

  1. Palms and SolesWhile we notice underarm sweat, the highest density of glands is on the hands and feet.
  2. 33The spine consists of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae.
  3. SmallpoxEdward Jenner used cowpox to immunize against smallpox in 1796.
  4. FourThe human heart has two atria (top) and two ventricles (bottom).
  5. BileBile is produced by the liver and stored/concentrated in the gallbladder.
  6. Deoxyribonucleic acidDNA is the hereditary material in humans and almost all other organisms.
  7. 7 poundsThe average birth weight is between 5.5 and 10 pounds.
  8. 5 feetThe large intestine is wider but much shorter than the small intestine (which is ~20ft).
  9. 2,000 to 10,000Taste buds are located in the papillae of the tongue and decrease as you age.
  10. 30,000Humans shed their entire outer layer of skin every 2-4 weeks.
  11. The liverThe liver is the largest and heaviest internal organ, weighing about 3-3.5 lbs.
  12. 206Humans are born with more bones (~300) which fuse together as they grow to reach ~206.
  13. Salk and SabinSalk developed the inactivated virus vaccine; Sabin developed the oral attenuated one.
  14. 1.2 to 1.5 gallonsBlood volume is roughly 7-8% of total body weight.
  15. RhnullRh-null has no Rh antigens at all; only about 50 people worldwide have it.
  16. SkinThe skin protects the body and regulates temperature; it can weigh up to 20 lbs.
  17. Three Gorges DamThe Three Gorges Dam in China has the world's largest installed capacity.
  18. Challenger DeepChallenger Deep is about 10,935 meters (35,876 ft) deep.
  19. ~62 poundsWater density changes slightly with temperature; it is densest at 4°C.
  20. 7Pure water is neutral on the pH scale, which ranges from 0 (acidic) to 14 (basic).
  21. 50 gallonsThe average American uses 80-100 gallons per day, but indoor use is around 50.
  22. About one weekWhile you can live weeks without food, water is essential for life processes after a few days.
  23. 40 times a yearThe atmosphere's water content is small but cycles extremely rapidly.
  24. EvaporationEvaporation is the primary way water moves from the surface to the atmosphere.
  25. More than 96%Less than 4% of Earth's total water is fresh; the rest is saline.
  26. Glaciers and ice capsOver 68 percent of the world's fresh water is locked up in ice and glaciers.
  27. 96.50%About 96.5 percent of all Earth's water is held in the oceans as saltwater.
  28. 71%Approximately 71% of Earth is water-covered, primarily by oceans.
  29. SevenLike humans and most mammals, giraffes have only seven cervical vertebrae, but they are very large.
  30. The Etruscan shrewThe Etruscan shrew is the smallest mammal by mass, weighing about 1.8 grams.
  31. The glass spongeThe glass sponge (Hexactinellid) can live for over 10,000 years.
  32. A cowAdult male elephants are called bulls, while females are called cows.
  33. A flamboyanceA group of flamingos is called a 'flamboyance' because of their bright colors.
  34. 15 minutesBeavers have physiological adaptations that allow them to stay submerged for long periods.
  35. Brine shrimpSea-Monkeys are a hybrid breed of brine shrimp sold as novelty aquarium pets.
  36. The mosquitoMosquitoes kill over 700,000 people annually by spreading diseases like malaria.
  37. BisonThe American Bison can weigh up to 2,000 pounds and stand 6 feet tall.
  38. The emuThe Great Emu War of 1932 was a nuisance wildlife management military operation in Australia.
  39. 110 feetThe largest recorded blue whale was a female measuring nearly 111 feet.
  40. 238,855 milesThe average distance is ~384,400 km or 238,855 miles.
  41. VenusVenus is often called Earth's twin due to its similar size, mass, and composition.
  42. Between Jupiter and MarsThe belt is located between the orbits of the inner rocky planets and the outer gas giants.
  43. Sally RideSally Ride became the first US woman in space in 1983 on the STS-7 mission.
  44. 90 minutesThe ISS travels at 17,500 mph, completing about 15.5 orbits per day.
  45. 356 billion yearsProxima Centauri is 4.2 light-years away; 70 mph is incredibly slow for interstellar travel.
  46. Nine yearsAt a steady walking pace without stopping, it would take about 9 years to cover the distance.
  47. UranusUranus has the coldest atmosphere, with temperatures reaching as low as -224°C.
  48. OneNeptune takes ~165 years to orbit; it was discovered in 1846 and finished its first orbit in 2011.
  49. Like a lemonThe moon is slightly elongated due to Earth's gravity, making it lemon-shaped.
  50. 4.6 billion years agoIt formed from a giant interstellar molecular cloud about 4.6 Gya.
  51. Mercury and VenusThe inner-most planets, Mercury and Venus, are the only ones without natural satellites.
  52. VenusVenus's thick CO2 atmosphere creates a runaway greenhouse effect, reaching 464°C.
  53. 230 million yearsThis vast period of time is often called a 'Cosmic Year'.
  54. 515,000 mphWe are traveling at over half a million miles per hour around the galaxy's center.
  55. BlueDust in the Martian atmosphere scatters blue light more effectively near the sun.
  56. At least a billion trillionThere are an estimated 1,000,000,000,000,000,000,000 stars (1 septillion).
  57. 800 yearsPluto is billions of miles away; even a fast plane would take centuries to arrive.
  58. IsotopesIsotopes have the same number of protons but different numbers of neutrons.
  59. ChlorineChlorine comes from the Greek 'chloros', meaning pale green.
  60. Antoine-Laurent LavoisierLavoisier established the law of conservation of mass and named oxygen and hydrogen.
  61. CarbonDiamonds are a solid form of pure carbon with its atoms arranged in a crystal structure.
  62. QuarksQuarks are elementary particles that combine to form composite particles called hadrons.
  63. 1901Jacobus van 't Hoff won the first prize in 1901 for his work on chemical dynamics.
  64. FeFe comes from the Latin word 'Ferrum'.
  65. Noble gassesNoble gases are inert because they have a full outer shell of electrons.
  66. 1912While Mendeleev created the first in 1869, the version based on atomic numbers came in 1912.
  67. Minus 40 degreesAt -40 degrees, both temperature scales intersect and read the same value.
  68. Oganesson (Og)Oganesson (118) was officially named in 2016, completing the 7th row.
  69. Einsteinium (Es)Einsteinium (atomic number 99) was discovered in the debris of the first hydrogen bomb.
  70. OxygenOxygen accounts for about 46% of the Earth's crust by weight.
  71. WaterHydrogen oxide (or dihydrogen monoxide) is simply the chemical name for water.
  72. SublimationSublimation occurs when a substance skips the liquid phase (e.g., dry ice).
  73. Mohs’ scaleThe Mohs scale ranks minerals from 1 (talc) to 10 (diamond).
  74. FissionNuclear fission releases a huge amount of energy by splitting heavy atoms.
  75. SeashellsConchology is the study and collection of mollusk shells.
  76. HemoglobinHemoglobin in red blood cells binds to oxygen to transport it through the body.
  77. At least six monthsStudies show goldfish can remember things for months, debunking the 3-second myth.
  78. PumicePumice is a volcanic rock full of air bubbles, giving it a density lower than water.
  79. 8 minutes and 20 secondsLight travels at ~300,000 km/s; the Sun is ~150 million km away.
  80. AntarcticaA desert is defined by low precipitation; Antarctica is the world's largest cold desert.
  81. Oxygen, Carbon, Hydrogen, NitrogenO, C, H, and N make up the vast majority of human biological molecules.
  82. RadiationGeiger counters detect ionizing radiation like alpha, beta, and gamma rays.
  83. ZeroSharks have skeletons made entirely of cartilage, not bone.
  84. OxygenPriestley isolated oxygen by heating mercuric oxide.
  85. NoThe Sun is 400x larger but also 400x further away, creating an illusion of equal size.
  86. Charles DarwinCharles Darwin published 'On the Origin of Species' in 1859.
  87. The United StatesThe U.S. experiences around 1,200 tornadoes per year due to its unique geography.
  88. MagmaMagma is below the surface; once it breaks the surface, it's called lava.
  89. Count its growth ringsEach ring typically represents one year of growth in a tree's life.
  90. UraniumUranium-235 is the primary fuel used in nuclear power plants.
  91. DormantA dormant volcano is one that hasn't erupted for a long time but could again.
  92. HydrogenHydrogen makes up about 75% of the elemental mass of the universe.
  93. MycologyMycology is the branch of biology concerned with the study of fungi.
  94. SevenThe rainbow consists of 7 colors: Red, Orange, Yellow, Green, Blue, Indigo, Violet.
  95. MeteorologyMeteorology focuses on atmospheric conditions and weather forecasting.
  96. An omnivoreOmnivores, like humans and bears, consume both plant and animal matter.
  97. 118There are 118 confirmed elements, from Hydrogen to Oganesson.
  98. Crust, mantle, and coreThe Earth consists of the outer crust, the thick mantle, and the central core.
  99. The cheetahThe cheetah can reach speeds up to 70 mph (112 km/h).
  100. JupiterJupiter is the gas giant with the largest mass and volume in our solar system.
  101. Fm (Fermium)This sequence follows the atomic numbers (1, 4, 9, 16, 25...) which are perfect squares. The next is 92 (Uranium).
  102. Infinite (mathematically)In a theoretical model with a restitution coefficient, the ball bounces infinitely many times with decreasing height.
  103. Toxic gasMixing bleach with ammonia-based cleaners creates toxic chloramine gas, which is lethal.
  104. Same heightTrees grow from the top (apical meristems), so a nail in the trunk stays at the same height.
  105. 3.16 timesThe Richter scale is logarithmic; an increase of 0.5 corresponds to about sqrt(10) or 3.16 times the energy.
  106. The letter EThis is a word riddle; the letter 'E' is the start of 'End' and the last letter of 'time' and 'space'.
  107. The MoonThe Moon goes through phases, including a 'Full Moon,' but it is a solid celestial body.
  108. StarsStars are always there but only become visible to us when the sun goes down.
  109. Dark energyDark energy is a mysterious force driving the universe's expansion, making up ~68% of it.
  110. MercuryMercury is a Roman god, the closest planet to the sun, and the liquid used in thermometers.
  111. FireFire requires fuel (food) to burn but is extinguished by water.
  112. A riverA river has a 'mouth' where it meets the sea, but obviously cannot chew anything.
  113. The bark of a treeThe bark is the outermost layer that surrounds the trunk but doesn't enter the interior wood.
  114. WetlandsWetlands are areas where water covers the soil, creating a unique, soggy ecosystem.
  115. SaltSalt is harvested from the sea and dissolves (disappears) when put back into water.
  116. Carbon, Oxygen, Phosphorus, SulfurThe symbols for Carbon (C), Oxygen (O), Phosphorus (P), and Sulfur (S) spell 'COPS'.
  117. A ferrous wheelA 'Ferrous Wheel' is a pun on 'Ferris Wheel' and the chemical term for iron (ferrous).
  118. They make up everythingA pun on 'Atoms' (the unit) 'making up' (inventing) things and being the fundamental building blocks of matter.
  119. KryptonKrypton is a noble gas in the same group as Neon, and also the name of Superman's home planet.
  120. NineThe chemical symbols Ni (Nickel) and Ne (Neon) spell 'NiNe'.
  121. ThoriumThorium is named after Thor, the Norse god of thunder.
  122. BariumThis is a classic pun riddle -- "barium," the chemical element, sounds just like "bury 'em," which is exactly what you'd do with the deceased chemist.
  123. Helium and AluminiumA pun on the symbols He and Al, which spell 'Heal'.
  124. CharcoalCharcoal is black, glows red when burning, and turns into grey ash when consumed.
  125. LeadA pun: 'Lead' is a metal, but the word 'lead' also means to be at the front or guide others.
  126. RustRust (iron oxide) forms when iron reacts with oxygen and water, essentially 'consuming' the metal.
  127. A black holeTime only moves in one direction�forward�according to the second law of thermodynamics.
  128. A light yearWordplay: A 'day' can be 'light' (daylight), unlike the night.
  129. The singularityA singularity is a point of infinite density, often described as 'one' or unique in space-time.
  130. The temperatureTemperature readings on a thermometer rise and fall without the device itself moving.
  131. The letter RThis is a wordplay riddle; the letter 'R' appears in the names of the first four mentioned planets but not the others.
  132. An X-rayX-rays have high energy and can pass through soft tissues but not bones, making them useful for imaging.
  133. EnergyThe Law of Conservation of Energy states energy cannot be created or destroyed.
  134. WaterWater can be steam (hot), ice (hard/cold), and flow through various substances.
  135. They weigh the sameA ton is a measure of weight, so 2000 lbs of anything weighs exactly the same.
  136. The letter VThis is a wordplay riddle; the letter 'v' is the literal middle letter of the word 'gravity'.
  137. A microwave particleMicrowaves are electromagnetic waves that vibrate water molecules to generate heat.
  138. An echoAn echo is a reflection of sound that returns to the source after a delay.
  139. SkinSkin is waterproof and bruises (changes color) when struck or injured.
  140. An eyeballAn eyeball is spherical and rotates (rolls) in the socket but cannot be bounced.
  141. You areHumans are primates, and you (the person answering) are the smartest primate in this scenario.
  142. ChromosomesHumans have 23 pairs of chromosomes, one set from each parent.
  143. HeightHeight refers to the measurement of how tall something is, which increases as you grow.
  144. BacteriaBacteria exist everywhere; some are beneficial (probiotics) while others cause disease.
  145. A tongueThe tongue contains taste buds but does not have olfactory (smell) receptors.
  146. A snailA snail carries its heavy shell everywhere it goes as its home.
  147. Your skullThe skull protects the brain (mind) and is located beneath the facial features.
  148. FeathersFeathers provide lift and insulation but require a bird's movement to fly.
  149. TeethTeeth are the hardest substance in the human body, similar to stone.
  150. Your breathYou can only hold your breath for a short time before needing to inhale.
  151. Your fingersA play on words; you use your fingers to count numbers.
  152. Carbon dioxidePlants use Carbon Dioxide for photosynthesis to produce food.
  153. The moonThe moon cycles through phases, changing how full it looks.
  154. A cloudA cloud moves in the sky (flies) and produces rain (cries).
  155. NeptuneThe blue planet known for the Great Dark Spot and extremely high winds.
  156. MercuryThe planet closest to the Sun's intense heat.
  157. MarsThe Red Planet known for its dusty and iron-rich surface.
  158. EarthOur planet is the third from the Sun in our solar system.
  159. A volcanoA mountain that erupts with hot lava.
  160. SnowFrozen precipitation that falls silently from the sky.
  161. FireFire consumes oxygen (needs air) and spreads (grows).