Do longer blades make a spinner fall slower?
- 👶 Small parts
- 🧍 Drop from standing: never climb
My hypothesis
If I change how long the spinner's blades are, then how long the spinner takes to fall will ______, because ______.
You fill in the blanks. Think about how big a circle the blades sweep as they spin, and how much air they push on. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
how long the spinner's blades are: 4 cm, 6 cm, 8 cm
MEASURE
how long the spinner takes to fall, in seconds
KEEP THE SAME
- the same kind of paper and the same size of strip
- one paper clip on the bottom of each
- dropping from the same height
- letting go without a push
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
- Paper: a sheet or two
- Paper clips: 3
- A stopwatch or a kitchen timer
- ✂️ Kid scissors
- 📏 A ruler
Steps
- Cut three strips of paper, each 5 cm wide and 20 cm long.
- Cut 4 cm down the middle of the first strip's top end, and fold the flaps out in opposite directions.
- Cut 6 cm down the second strip and 8 cm down the third, and fold their flaps out the same way.
- Fold the bottom 2 cm of each strip up, and slide a paper clip on it.
- Hold the 4 cm spinner by its clip, blades up, as high as you can reach. Never climb.
- Let go as a helper starts the timer, and stop it when the spinner lands.
- Write the time down, then drop it four more times.
- Do five drops with the 6 cm spinner, then five with the 8 cm spinner.
- Find the mean for each blade length 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: Do longer blades make a spinner fall slower?
I changed: Blade length I measured: how long the spinner takes to fall (seconds)
| Blade length | Try 1 (seconds) | Try 2 (seconds) | Try 3 (seconds) | Try 4 (seconds) | Try 5 (seconds) | Mean |
|---|---|---|---|---|---|---|
| 4 cm | ||||||
| 6 cm | ||||||
| 8 cm |
MY GRAPH (a line graph: blade length 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: Do longer blades make a spinner fall slower?
If I change how long the spinner's blades are, then how long the spinner takes to fall will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Blade length: 4 cm, 6 cm, 8 cm | how long the spinner takes to fall (seconds) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Do longer blades make a spinner fall slower?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do longer blades make a spinner fall slower?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do longer blades make a spinner fall slower?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do longer blades make a spinner fall slower?
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: add 1, 2 and 3 paper clips to the best spinner, and graph fall time against the number of clips.
Why it works
As the spinner falls, air pushes up on its tilted blades and makes them whirl. Spinning blades work like little wings, pushing air down so that the air pushes them up, and that slows the fall. Longer blades sweep a bigger circle and push on more air, so they usually fall slower.
Going further (7th and up): Change a second thing: add 1, 2 and 3 paper clips to the best spinner, and graph fall time against the number of clips.
Board layout
- ❓ Question (10 × 8 in): Do longer blades make a spinner fall slower?
- 💭 Hypothesis (10 × 9 in): If I change how long the spinner's blades are, then how long the spinner takes to fall 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 (Blade length 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: Paper; Paper clips; 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: add 1, 2 and 3 paper clips to the best spinner, and graph fall time against the number of clips. |
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 long the spinner's blades are and measured how long the spinner takes to fall, in seconds.
- What did you keep the same, and why does that matter? I kept the same kind of paper and the same size of strip and one paper clip on the bottom of each the same, so the only difference was how long the spinner's blades are.
- 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 add 1, 2 and 3 paper clips to the best spinner, and graph fall time against the number of clips.
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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