At the school field, Rocket rolls a soccer ball slowly into a pile of leaves. A few leaves flutter.
Then he kicks the ball hard into the pile. Leaves burst into the air like confetti!
Raven writes in her notebook. "Same ball, same pile. What do you notice about the speed before each crash?"
Nova floats above the leaves. "Here is a clue," she says. "Compare the speed before the crash with what happened after."
Last week you learned that a faster object has more energy.
So a faster object can transfer more energy when it collides.
A slow ball barely moves the leaves. A fast ball sends them flying and makes a louder sound.
Scientists look at before and after. The speed before the crash helps explain the change after.
| Before the crash | After the crash |
|---|---|
| Ball rolls slowly | A few leaves flutter, soft rustle |
| Ball kicked fast | Leaves burst up, loud whoosh |
| Statement | True or false? |
|---|---|
| A faster ball can transfer more energy to the leaves. | ? |
| The slow ball made the leaves fly the highest. | ? |
| The fast crash made a louder sound. | ? |
| Speed before a crash has nothing to do with what happens after. | ? |
Scientists use patterns to predict what will happen next.
Our pattern: the faster an object is before a crash, the more energy it can transfer.
So if Rocket kicks the ball even harder, the leaves should fly even higher.
And the whoosh should be even louder.
| Statement | True or false? |
|---|---|
| A slow marble has little energy to give in a crash. | ? |
| Scientists use patterns to predict what will happen. | ? |
| A faster kick sends the leaves less high. | ? |
You are thinking like a crash scientist. Tomorrow we see how engineers make crashes safer.