When we call something a puzzle, rather than just a problem or a question, we are often focusing on the recreational aspect of coming up with a solution. The enjoyment derived from solving a puzzle can help fix scientific lessons in memory.
The following quiz is not a puzzle, but it is made up of puzzling questions that may surprise and stretch the mind in a satisfying way, and perhaps help reinforce or teach some scientific ideas. It is not meant to test your knowledge, but to drive home some principle of science or to illustrate some surprising phenomenon.
1. What really came first, the chicken or the egg?
a) The question leads to infinite regress. There can be no right answer.
b) The chicken. Without adult chickens, no eggs could be laid.
c) The egg. Eggs definitely existed before there were chickens.
d) The answer is still unknown.
2. If a heavy metallic object is thrown straight up and falls straight down in a vacuum, it would take exactly equal time on the upward and downward journeys. What happens in the presence of air?
a) No difference. It takes exactly the same time.
b) It takes longer on the downward journey.
c) It takes longer on the upward journey.
d) It varies depending on the direction of the airflow.
3. What’s the smallest number of people in a group for there to be an even or greater chance of two of them sharing a birthday?
4. If you had US$10 billion (only a fifth of the assets of Microsoft chairman Bill Gates) and invested it to yield 4 percent interest per year, how much could you then afford to spend every day such that you never touch a penny of your principal for the rest of eternity (assuming, of course, that our economic system and humanity survive indefinitely)?
a) A luxurious US$1,000 a day.
b) A super luxurious US$10,000 a day.
c) An unbelievable US$100,000 a day.
d) An unimaginable US$1 million a day.
5. If you threw a heavy metallic object from a floating boat into a pond, what would happen to the level of water in the pond?
a) It would stay the same.
b) It would go up slightly.
c) It would go down slightly.
d) It depends on the weight of the object.
6. You see a certain car license plate, and after the event you calculate the probability of having seen this particular license number to be 1 in 30 million. How do you explain this?
a) It was a rare coincidence, and will probably never happen again.
b) This happens all the time — calculating the odds after something happens is meaningless.
c) It is a result of synchronicity.
d) Everything happens for a reason.
7. Land mammals like human beings or lab mice breathe air through their lungs. Is it possible for them to ever breathe liquids?
a) Yes, no problem. After all, that’s what sea mammals like whales and dolphins do.
b) Never. The liquid in the lungs would cause them to drown.
c) Never. A liquid in the lungs would prevent oxygen from reaching the blood.
d) Yes, it is possible to keep a land mammal alive in the lab temporarily breathing a liquid.
8. We perceive sound because of the sound waves that fall on our ears, right? What if I told you that what people see can completely change their perception of sounds that they hear?
a) That’s impossible. Sound energy and light energy are distinct.
b) That’s possible only in some select individuals who have a condition called synesthesia.