Which floor makes a ball bounce highest?
- ✅ Nothing sharp, hot or small
My hypothesis
If I change the floor the ball lands on, then how high the ball bounces will ______, because ______.
You fill in the blanks. Think about where the ball's energy goes when it squashes into something soft. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
the floor the ball lands on: Carpet, Hard floor (wood or tile), A folded towel
MEASURE
how high the ball bounces, in cm
KEEP THE SAME
- the same ball
- dropping it from the same height
- letting go, never throwing
Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 3 levels 3 times.
What you need
- A tennis ball or a playground ball
- A tape measure, or a long ruler
- Masking tape, to mark lines
Steps
- Tape the tape measure up a wall, with 0 at the floor.
- Hold the ball next to the tape at 100 cm.
- Let go. Don't throw it!
- A helper watches how high the bottom of the ball gets on the first bounce.
- Write the number in your table.
- Drop it two more times on the same floor.
- Move to a different floor and do three more drops.
- Lay a folded bath towel down and do three drops on it.
- Draw a bar for each floor. Which bounced highest?
Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.
Your results table
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
I changed: Floor I measured: how high the ball bounces (cm)
| Floor | Try 1 (cm) | Try 2 (cm) | Try 3 (cm) | Mean |
|---|---|---|---|---|
| Carpet | ||||
| Hard floor (wood or tile) | ||||
| A folded towel |
MY GRAPH (a bar graph: floor along the bottom, cm up the side)
What I noticed: ______________________________________________
From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a bar graph, one bar for each thing you tried.
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
If I change the floor the ball lands on, then how high the ball bounces will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Floor: Carpet, Hard floor (wood or tile), A folded towel | how high the ball bounces (cm) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor makes a ball bounce highest?
My hypothesis was ☐ right ☐ partly right ☐ not right.
I know because my numbers show:
What surprised me, or what might have gone wrong (7th and up):
Next time I would test:
Idea: Change a second thing: drop the ball from 50, 100 and 150 cm on each floor, and draw a line for each floor.
Why it works
When the ball hits the floor it squashes, then springs back and pushes itself up again. A hard floor hardly squashes at all, so most of the energy goes back into the ball. A soft floor squashes too and keeps some of the energy, so the bounce is lower.
Going further (7th and up): Change a second thing: drop the ball from 50, 100 and 150 cm on each floor, and draw a line for each floor.
Board layout
- ❓ Question (10 × 8 in): Which floor makes a ball bounce highest?
- 💭 Hypothesis (10 × 9 in): If I change the floor the ball lands on, then how high the ball bounces will ______, because ______.
- 🧺 Materials (10 × 12 in): 3 things: see your list.
- 🪜 Steps (22 × 9 in): 9 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Floor down the side, tries across) and your bar graph.
- ✅ Conclusion (10 × 14 in): My hypothesis was right / partly right / not right. I know because…
Materials to list: A tennis ball or a playground ball; A tape measure, or a long ruler; Masking tape, to mark lines.
Bring photos or drawings of your test. Nothing wet, hot, powered or alive on the table.
This project at your grade
| 1st–3rd grade | Tries: three at each level (one is fine at a first fair). The table: levels and tries, numbers or pictures. The graph: a picture, or a simple bar graph. The conclusion: what happened, in their words. |
|---|---|
| 4th–6th grade | Tries: three at each level. The table: units in the header and a mean column. The graph: a bar graph, or a line for a number that grows. The conclusion: right, partly or not, and the numbers that show it. |
From 4th grade up, the table gets a mean column. See every project for 1st grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed the floor the ball lands on and measured how high the ball bounces, in cm.
- What did you keep the same, and why does that matter? I kept the same ball and dropping it from the same height the same, so the only difference was the floor the ball lands on.
- How many times did you test it? 3 times at each of my 3 levels.
- If you did it again, what would you change or test next? I'd drop the ball from 50, 100 and 150 cm on each floor, and draw a line for each floor.
Make it yours
Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.
Try next
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