Hard Science Trivia Questions

33 hard science trivia questions with answers

1. What is the lightest element on the periodic table?

   Answer: Hydrogen A single proton and one electron make up the ordinary atom.Why?

2. Which particle carries a negative electric charge?

   Answer: Electron Its movement through a wire is what we call electric current.Why?

3. What is the process by which a solid turns directly into a gas?

   Answer: Sublimation Dry ice does this at room temperature, skipping any liquid stage.Why?

4. Which part of the brain controls balance and coordination?

   Answer: Cerebellum It sits at the back of the skull, beneath the larger cerebrum.Why?

5. What is the pH of pure water at room temperature?

   Answer: 7 Seven is neutral, neither acidic nor alkaline.Why?

6. Which acid is found in the human stomach?

   Answer: Hydrochloric acid A mucus lining stops the stomach from digesting itself.Why?

7. Which scientist is credited with formulating the theory of evolution by natural selection?

   Answer: Charles Darwin Alfred Russel Wallace reached a very similar conclusion independently.Why?

8. Absolute zero corresponds to what temperature in Celsius?

   Answer: About minus 273 degrees It is the point at which particle motion reaches its theoretical minimum.

9. Which subatomic particle determines the identity of a chemical element?

   Answer: The proton Change the neutron count instead and you get an isotope, not a new element.Why?

10. Which organelle is described as the powerhouse of the cell?

    Answer: Mitochondrion It carries its own small loop of DNA, inherited from the mother.Why?

11. The bends, suffered by divers surfacing too fast, is caused by bubbles of which gas?

    Answer: Nitrogen Dissolved nitrogen comes out of solution as the surrounding pressure drops.

12. Which type of electromagnetic radiation has the longest wavelength?

    Answer: Radio waves Longer wavelength means lower frequency and lower energy per photon.Why?

13. The half-life of a radioactive isotope describes what?

    Answer: Time for half the atoms to decay The rate is statistical, so it holds no matter how much you start with.

14. Which blood vessel type has walls only one cell thick?

    Answer: Capillaries That thinness is what allows gases and nutrients to diffuse across.Why?

15. Venus rotates in the opposite direction to most planets. What is this called?

    Answer: Retrograde rotation Its spin is so slow that a day on Venus lasts longer than its year.

16. After the Sun, which star is closest to Earth?

    Answer: Proxima Centauri It lies about 4.2 light years away, a red dwarf too faint to see with the naked eye.

17. Which object is so dense that not even light can escape its gravity?

    Answer: Black hole The boundary beyond which nothing returns is called the event horizon.

18. The point in a planet's orbit closest to the Sun is called what?

    Answer: Perihelion Earth reaches it in early January, not in northern summer, which surprises many people.

19. Which scale rates the strength of tornadoes?

    Answer: Fujita scale Saffir-Simpson is for hurricanes and Beaufort for ordinary wind speed.

20. Stalactites and stalagmites form in caves carved from which rock?

    Answer: Limestone Slightly acidic water dissolves the calcium carbonate and redeposits it drip by drip.

21. A boundary where two tectonic plates slide past each other sideways is called what?

    Answer: Transform boundary The San Andreas Fault in California is the best-known example.

22. Most of the ozone layer sits in which layer of the atmosphere?

    Answer: Stratosphere Almost all weather happens below it, in the troposphere.

23. Which metal has the highest melting point?

    Answer: Tungsten At around 3,400 degrees Celsius, it made the ideal filament for incandescent light bulbs.

24. Sodium bicarbonate is better known in the kitchen as what?

    Answer: Baking soda Baking powder contains it plus a dry acid, so the two are not interchangeable in recipes.

25. Avogadro's number is approximately what?

    Answer: 6.02 × 10^23 It is the number of particles in one mole of any substance.

26. A bond in which two atoms share a pair of electrons is called what?

    Answer: Covalent bond Ionic bonds transfer electrons outright, as in table salt.

27. Which acid gives vinegar its sharp taste?

    Answer: Acetic acid Household vinegar is typically 4 to 8 percent acetic acid in water.

28. How many pairs of chromosomes does a typical human body cell contain?

    Answer: 23 pairs That makes 46 in total, half inherited from each parent.

29. Which part of the eye controls how much light enters it?

    Answer: Iris It widens the pupil in dim light and narrows it in bright light.

30. Hair and nails are made mainly of which protein?

    Answer: Keratin The same protein forms feathers, hooves and horns in other animals.

31. Frequency is measured in which SI unit?

    Answer: Hertz One hertz is one cycle per second.

32. In the equation E = mc², what does m stand for?

    Answer: Mass Because c² is so large, a tiny mass corresponds to an enormous amount of energy.

33. Who discovered X-rays in 1895?

    Answer: Wilhelm Röntgen He called them X because their nature was unknown, and won the first Nobel Prize in Physics for the work.