How tiny stones inside our heads tell us which way is up...
Why don't the cornflakes at the bottom of the box get crushed by the weight of the flakes on top?
Why are the planets where they are instead of somewhere else?
Nowadays everybody knows there are nine planets in our solar system, but that information was hard won.
A skydiver's body is in a delicate balance. Gravity tugs her downward with a constant, relentless force, while air resistance pushes her upward.
Every skydiver experiences two different forces: the tug of gravity and the upward push of air resistance.
When a kicker kicks the football down field, what is he calculating?
You stomp at an ant crawling along the baseboard, and it escapes by climbing the wall. How do insects deal with gravity?
Black holes were always the most dangerous thing when traveling through space in science fiction shows. What are black holes and how do they form?