Does a ball dropped from higher bounce higher?
- 🧍 Drop from standing: never climb
My hypothesis
If I change the height the ball is dropped from, then how high the ball bounces will ______, because ______.
You fill in the blanks. Think about how fast the ball is going when it hits the floor. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
the height the ball is dropped from: 25 cm, 50 cm, 75 cm, 100 cm
MEASURE
how high the ball bounces, in cm
KEEP THE SAME
- the same ball
- the same floor
- letting go, never throwing
- measuring the bottom of the ball at the top of its first bounce
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 4 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, with its bottom at 25 cm.
- Let go. Don't throw it! Stand on the floor and never climb.
- A helper crouches by the tape and watches how high the ball's bottom gets on its first bounce.
- Write the height in your table under Try 1.
- Drop it two more times from 25 cm, and write each one down.
- Do three drops from 50 cm, then three from 75 cm, then three from 100 cm.
- Find the middle number for each height, and draw a line graph.
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: Does a ball dropped from higher bounce higher?
I changed: Drop height I measured: how high the ball bounces (cm)
| Drop height | Try 1 (cm) | Try 2 (cm) | Try 3 (cm) | Mean |
|---|---|---|---|---|
| 25 cm | ||||
| 50 cm | ||||
| 75 cm | ||||
| 100 cm |
MY GRAPH (a line graph: drop height 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 line graph, because the thing you change is a number that goes up.
Name ______________________ Fair day ____________
Question: Does a ball dropped from higher bounce higher?
If I change the height the ball is dropped from, then how high the ball bounces will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Drop height: 25 cm, 50 cm, 75 cm, 100 cm | how high the ball bounces (cm) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Does a ball dropped from higher bounce higher?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a ball dropped from higher bounce higher?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a ball dropped from higher bounce higher?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a ball dropped from higher bounce higher?
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 onto carpet as well as a hard floor from each height, and draw a line for each floor.
Why it works
A ball speeds up as it falls, so a ball dropped from higher hits the floor harder and squashes more. The squashed ball springs back and pushes itself up, so it usually bounces higher. It never gets all the way back up, because some energy leaves as sound and a little warmth each time it lands.
Going further (7th and up): Change a second thing: drop the ball onto carpet as well as a hard floor from each height, and draw a line for each floor.
Board layout
- ❓ Question (10 × 8 in): Does a ball dropped from higher bounce higher?
- 💭 Hypothesis (10 × 9 in): If I change the height the ball is dropped from, then how high the ball bounces will ______, because ______.
- 🧺 Materials (10 × 12 in): 3 things: see your list.
- 🪜 Steps (22 × 9 in): 8 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Drop height down the side, tries across) and your line 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 height the ball is dropped from 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 the same floor the same, so the only difference was the height the ball is dropped from.
- How many times did you test it? 3 times at each of my 4 levels.
- If you did it again, what would you change or test next? I'd drop the ball onto carpet as well as a hard floor from each height, 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
👨👩👧 For grown-ups and teachers: how much to help, the safety rules, and running a school fair. Science fair v0.16.1 · Checked .