Rocket builds a tall tower of wooden blocks in the garage. Then he aims his toy race car right at it.
Zoom! The car hits the bottom block. Crash! The tower tumbles and the car stops dead.
"The car was moving and the blocks were still," Raven says. "Now it is the other way around. What do you notice?"
Nova scans the fallen blocks. "Interesting," she says. "The energy did not vanish. Where do you think it went?"
To collide means to bump or crash into something. The bump is called a collision.
When objects collide, energy can transfer from one object to another. Transfer means move from one thing to another.
That is why the still blocks started moving. The car passed its motion energy to them.
A collision changes how objects move. Some speed up, some slow down, and some change direction.
| Statement | True or false? |
|---|---|
| A collision can make a still object start moving. | ? |
| In a collision, energy can transfer from one object to another. | ? |
| After a collision, every object always keeps the same speed. | ? |
Here is a rule scientists have tested many times. Energy is never created or destroyed.
Instead, energy moves from one object to another, or it changes form.
So when the car stopped, its energy did not vanish. Some moved into the blocks.
Some became the crash sound you heard. Energy always goes somewhere.
Nice work, energy detective! Tomorrow we listen and feel for energy that escapes in a crash.