Rocket props the cardboard ramp on the bottom step. "The ramp gives the same push every time," he says.
Raven sets a tennis ball at a tape mark near the top. "This is the pusher. It rolls down and bumps the target."
At the bottom she places the foam ball. Rocket lets go. The tennis ball rolls, taps the foam ball, and it shoots away.
Raven measures. "Two metres ten." She swaps in the heavy playground ball. Same release. It rolls thirty centimetres.
"What do you notice?" she asks.
"Same pusher, same ramp, same push," Rocket says. "The heavy target barely moved."
Nova dips over the tape measure. "Now do it again. Once is a story. Three times is data."
Today a ramp gives the same push to two targets of different mass. You measure how far each target rolls.
The pusher ball always starts from the same mark. That keeps its push on the target as equal as you can make it.
Predict, measure three times each, then compare.
| Target | Roll 1 (centimetres) | Roll 2 (centimetres) | Roll 3 (centimetres) | Average (centimetres) |
|---|---|---|---|---|
| Foam ball (less mass) | ||||
| Heavy ball (more mass) |
The pusher gave both targets about the same push. The foam ball, with less mass, changed its motion more and rolled farther.
The heavy ball, with more mass, changed its motion less and rolled a shorter way.
This is Newton's second law at the Field. Same force, more mass, smaller change in motion.
Your three rolls will not match exactly. The pusher may wobble or hit the target a little off center. Averaging helps.
In the last step, you released both balls together. Write down what you saw. Next week explains it.
| What the lab shows | True or false? |
|---|---|
| The foam ball rolled farther than the heavy ball after the same bump. | ? |
| The ramp gives a bigger push to the heavy ball. | ? |
| Averaging three rolls gives a fairer number than one roll. | ? |
| The test changed two things at once: the mass and the push. | ? |
Careful work. Tomorrow you will read a table that separates mass from weight.