2) Why is the string on a flying kite not taut?
3) How can one make a swing go higher just by pumping one's legs? Isn't this a closed physical system? Why don't actions and reactions cancel one another?
4) Certain animals, such as chameleons and iguanas, can change the colors of their bodies to match the background. What would happen if you were to place such an animal on a background so that its left eye saw a light background and its right eye a dark one?
5) What is eye contact? How do we know when we have achieved it? Can humans make eye contact with animals? If so, which ones?
6) What is itching and how does scratching alleviate the problem?
7) Is hunger nutrient specific? For example, does a person whose body is low in sodium crave salty food?
8) How does rubbing a razor back and forth on a leather strap sharpen it?
9) Why does snow squeak when you step on it when the temperature is very cold but not when it is moderately cold?
10) How does plastic wrap (like Saran Wrap) work? What makes it cling to itself (on either side)? Why doesn't it work when it is wet or cold?
11) If you rub a balloon on a sweater, the balloon will stick to a wall or other surface because of static electricity. Why are the electrons transferred from one material to the other in only one direction? Why doesn't the balloon discharge when it touches the sweater again?
12) Why do ripples form on sand?
13) If moisture laden air is heavier than dry air, why is low barometric pressure associated with wet, stormy weather and high pressure with clear, dry weather?
14) When there is heavy traffic on a highway and no accidents or obstructions, why is the driving characterized by stopping and going rather than continuous driving at a slow speed?
15) How is it possible for the sea levels to be different on either side of the Panama Canal even though the Atlantic and Pacific Oceans are connected?
16) Do any creatures other than humans and horses perspire?
17) As viewed from the Celestial North, do all of the planets in our solar system rotate on their axes in the same direction? Do they all rotate at least as fast as their revolutionary speeds? (That is, does the sun rise in the east for all planets other than Mercury, where it never rises nor sets?)
18) Why do some vehicles have "one-way" tires and which way should they be put on?
19) What is the etymological difference between the phrases "a few" and "few"? Consider the sentence: "I have few worries." Compare it to: "I have a few worries." In the first sentence, one is asserting the absence of worries while in the second one is noting their presence.
20) In a darkroom, used for developing photographic film, there is usually a dim red light that is supposedly of too low a frequency to affect the film. How, then, can one account for photographs of darkrooms with red lights?
21) Why do mirrors appear to reverse left and right but not up and down?
22) Why do certain types of flies bite people? Are they actually trying to eat us?
23) If a person were to hit his or her finger with a hammer, he or she would most likely exclaim something ranging from "Ouch!" to something rather more crude. Why do people make a noise when they hurt themselves?
24) It is commonly claimed that fingerprints are unique. What justifies this claim? Does the claim mean that ALL of my fingerprints are different from ALL of yours or does it mean that just SOME differ? Can one of my fingerprints (say the left index finger) match a different one (say the left middle finger) of yours?
25) What is the origin of the dual use of the letter V in Latin to signify either a V or a U?
26) What is sleep? Is it well defined? Do all animals sleep? Do clams sleep, for example? How would we know?
27) How did sleep make it through the evolutionary sieve? Surely a sleeping animal is much more vulnerable to predators than an alert one. Wouldn't animals that don't require sleep (if there are any) prevail over those that do in natural selection? Isn't hibernation even less likely to have succeeded as a survival mechanism?
