🥶 Ball temperature and bounce: the whole packet

🥶 Ball temperature and bounce · 4th–8th grade · 1 day of testing · about $3 · 60 minutes a sitting

My days, if the fair is 14 days away

Count back from your fair day and write in each date. Fewer days than this? The jobs share days, in this order; nothing is skipped.

Dates from my teacher

• My question is due
• Testing starts
• My results table and graph are due
• My board is due

In this packet

1. 🗓️ My project plan
2. 💭 My hypothesis
3. 🧺 Change, measure, keep the same
4. 🪜 My steps
5. 📊 My results
6. 📓 My logbook
7. ✅ My conclusion
8. ✂️ Board titles to cut out
9. 🏅 The judge's questions and my certificate

If I change how warm the ball is, then how high the ball bounces will ________________, because _____________________________________________

What I think will happen, in my own words:

3 levels × 3 tries at each = 9 tries in all. If anything you keep the same changes, you won't know which change made the difference.

What I need

• 🎾 A tennis ball or a playground ball: 1
• 🛍️ Plastic bags: a zip bag that fits the ball
• 🥣 A big bowl
• 🚰 Warm water
• 🌡️ A thermometer (digital, or the red-liquid kind)
• 📏 A tape measure, or a long ruler
• 🩹 Masking tape, to mark lines
• ⏱️ A stopwatch or a kitchen timer

Be safe: 🧍 Drop from standing: never climb · 💧 Water

1. Tape the tape measure up a wall, with 0 at the floor, and mark 100 cm with masking tape.
2. Read the thermometer in the room and write the temperature down.
3. Hold the ball with its bottom at the mark and let go. Stand on the floor: never climb.
4. A helper crouches by the tape and watches how high the ball's bottom gets on its first bounce.
5. Write the height down, then drop the ball two more times, quickly.
6. Seal the ball in a zip bag and leave it in the fridge, next to the thermometer, for 15 minutes.
7. Read the thermometer, then take the ball out of its bag and drop it at once from the mark.
8. Drop it twice more in under a minute, and write all three heights down.
9. Run the tap until the water feels warm like a bath, never hot, and fill a bowl.
10. Check the water with the thermometer and write the temperature down.
11. Seal the ball in a zip bag and float it in the bowl for 15 minutes, turning it once.
12. Take the ball out of its bag and drop it three times in under a minute, writing each height down.
13. Find the mean for each temperature and draw a line graph.

Write each number in your results table the moment you measure it.

I changed: Ball temperature   I measured: how high the ball bounces (cm)

MY GRAPH (a line graph: ball temperature along the bottom, cm up the side)

What I noticed: ______________________________________________

Write something every day you work on it, even the days you only gather things. More days? The three-page logbook prints from peabody.kids/science-fair/templates/logbook.

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: test a second kind of ball at the same three temperatures, and graph each ball's bounce height divided by its drop height.

1. What made you want to ask this question? Say something like: I wanted to know: does a cold ball bounce lower than a warm one?
2. What did you think would happen, and why? Say something like: I thought changing how warm the ball is would change how high the ball bounces, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed how warm the ball is (Cold (from the fridge), Room, Warm (from warm water)) and measured how high the ball bounces in cm.
4. What did you keep the same, and why does that matter? Say something like: I kept the same ball and dropping it from the same 100 cm mark the same, so only how warm the ball is was different.
5. How many times did you test it? Say something like: 3 times at each of my 3 levels, and I found the middle number.
6. What did you find out? Show me in your numbers. Say something like: Look at my table: Cold (from the fridge) and Warm (from warm water) gave different numbers, and here's the pattern.
7. Was your hypothesis right? How do you know? Say something like: My numbers show whether I was right, partly right or not, and I can show you where.
8. Did anything go wrong, or surprise you? Say something like: One try was odd, so I did it again and wrote it in my logbook.
9. If you did it again, what would you change or test next? Say something like: I'd change a second thing: test a second kind of ball at the same three temperatures, and graph each ball's bounce height divided by its drop height.