Beckett has been fascinated by batteries for as long as I can
remember, so his latest suggestion for a science topic should
not have been a surprise. Beckett wanted to know how toys work.
We talked about the mountain of toys he has and about the energy
makes them work -- whether the energy comes from him pushing a
car or throwing an airplane, or from batteries or rubber bands.
This led naturally enough to a discussion about potential energy
and kinetic energy. Potential energy is stored energy, energy
that is waiting to be used, and it comes in many forms. The most
basic form of potential energy is provided by gravity -- an
object that is not at rest on the surface of the earth probably
has some potential gravitational energy in it. We pulled out one
of Rowan's toys and asked him to demonstrate. When the ball is
poised at the top of the ramp, it has potential energy. Gravity
is pulling it down, but until it is free to move, the energy is
being stored in it. As soon as Rowan lets go, gravity begins
pulling the