Does a bigger disc make a top spin longer?
- 👶 Small parts
My hypothesis
If I change how big the disc on the top is, then how long the top spins will ______, because ______.
You fill in the blanks. Think about what keeps a big wheel turning once it is going, and what slows it down. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
how big the disc on the top is: Small (a bottle cap), Medium (a cup bottom), Big (a bowl bottom)
MEASURE
how long the top spins, in seconds
KEEP THE SAME
- the same pencil
- the disc taped the same distance up from the tip
- discs cut from the same thin cardboard
- one firm twist, the same way, every time
- the same smooth table
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 5 times.
What you need
- Flat cardboard: thin, like a cereal box
- A bottle cap
- Paper cups: 1
- A big bowl
- A pencil
- A stopwatch or a kitchen timer
- ✂️ Kid scissors
- 🩹 Tape
- 📏 A ruler
Steps
- Trace a bottle cap, a paper cup's bottom and a bowl's bottom on thin cardboard, and cut out the discs.
- Measure across each disc with the ruler, and write the sizes in your table.
- Grown-up: A grown-up pokes the pencil point through the middle of each disc, to start a hole that just fits.
- Push the pencil through the small disc, and tape it on 2 cm up from the tip.
- Stand the top on a smooth table, twist the pencil between finger and thumb, and let go.
- A helper starts the timer when you let go, and stops it when the top falls over.
- Write the time in your table, then spin it four more times, twisting the same way.
- Slide the disc off, tape on the medium disc 2 cm up, and do five spins.
- Swap in the big disc the same way and do five more spins.
- Find the mean for each disc size and draw a line graph.
One step is a grown-up's, marked above. Write each number down straight away, in the table below, so nothing is lost.
Your results table
Name ______________________ Fair day ____________
Question: Does a bigger disc make a top spin longer?
I changed: Disc size I measured: how long the top spins (seconds)
| Disc size | Try 1 (seconds) | Try 2 (seconds) | Try 3 (seconds) | Try 4 (seconds) | Try 5 (seconds) | Mean |
|---|---|---|---|---|---|---|
| Small (a bottle cap) | ||||||
| Medium (a cup bottom) | ||||||
| Big (a bowl bottom) |
MY GRAPH (a line graph: disc size along the bottom, seconds 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 bigger disc make a top spin longer?
If I change how big the disc on the top is, then how long the top spins will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Disc size: Small (a bottle cap), Medium (a cup bottom), Big (a bowl bottom) | how long the top spins (seconds) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Does a bigger disc make a top spin longer?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a bigger disc make a top spin longer?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a bigger disc make a top spin longer?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Does a bigger disc make a top spin longer?
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: tape 0, 2 and 4 pennies evenly around the edge of the medium disc, and graph how the spin time changes.
Why it works
A spinning top keeps turning because anything spinning wants to keep spinning. A big, flat disc has its weight far from the middle, so it is hard to slow down and keeps the top turning longer. A very big disc is also heavier, so there may be a size that works best.
Going further (7th and up): Change a second thing: tape 0, 2 and 4 pennies evenly around the edge of the medium disc, and graph how the spin time changes.
Board layout
- ❓ Question (10 × 8 in): Does a bigger disc make a top spin longer?
- 💭 Hypothesis (10 × 9 in): If I change how big the disc on the top is, then how long the top spins will ______, because ______.
- 🧺 Materials (10 × 12 in): 6 things: see your list.
- 🪜 Steps (22 × 9 in): 10 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Disc size 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: Flat cardboard; A bottle cap; Paper cups; A big bowl; A pencil; A stopwatch or a kitchen timer.
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. |
| 7th grade and up | Tries: three or more at each level. The table: a mean for every level of both tests. The graph: a graph with two lines or two sets of bars. The conclusion: the numbers, what might have gone wrong, and a next question. Second variable: tape 0, 2 and 4 pennies evenly around the edge of the medium disc, and graph how the spin time changes. |
From 4th grade up, the table gets a mean column. See every project for 3rd grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed how big the disc on the top is and measured how long the top spins, in seconds.
- What did you keep the same, and why does that matter? I kept the same pencil and the disc taped the same distance up from the tip the same, so the only difference was how big the disc on the top is.
- How many times did you test it? 5 times at each of my 3 levels.
- If you did it again, what would you change or test next? I'd tape 0, 2 and 4 pennies evenly around the edge of the medium disc, and graph how the spin time changes.
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 .