Changing energy
Crack! It’s a home run—and it was scored by a hamburger!
It’s true that the hamburger didn’t hit the ball. The batter did. But
the batter ate the hamburger for lunch. The batter’s body got energy
from the hamburger. Some of this energy was used to swing the bat. And
the energy in the swinging bat knocked the ball over the fence. So stand
up and cheer for the hamburger—it scored the home run!
There are only a few kinds of energy. But each kind of energy can change
into other kinds. Chemical energy in the food you eat can be changed
into kinetic energy when you run or hit a ball. And other energy changes
can be used to make other things work.
Here are two moving toys you can make that use energy in dilferent ways.
The first toy gets energy from something else that moves—the wind. But
the second one works when heat energy changes into the energy of moving
things.
A wind-skipper
Materials:
cardboard (thin)
paste
pencil
scissors
tracing paper
This toy doesn’t fly like a kite. But it will skip and spin down a
sidewalk on a breezy day.
Fold the tracing paper in half. Place the folded edge along the dotted
line and trace
the half-pattern shown here. Turn the folded paper over and trace the
other half. Open the paper and paste it on the cardboard. Then cut out
the pattern.
First, cut around the outside circle. Then poke your scissors through
the center. Cut along each line just to the inner circle.
Next bend the points as shown here—one up, one down, until you have
gone all around the circle.
Set your wind-skipper on the sidewalk. The eight points will act like
small sails. They will catch a push from the wind, and the windskipper
will twirl along the ground.
