Which floor slows a toy car the most?
- ✅ Nothing sharp, hot or small
My hypothesis
If I change the floor the car rolls on, then how far the car rolls will ______, because ______.
You fill in the blanks. Think about what happens between the wheels and the floor as the car rolls. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
the floor the car rolls on: Bare floor (tile or wood), Carpet, A bath towel
MEASURE
how far the car rolls, in cm
KEEP THE SAME
- the same car
- the same ramp, 2 books high
- the same start line on the ramp
- 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 3 times.
What you need
- A toy car
- Some books: 2, about the same thickness
- Flat cardboard: a long flat piece, about 60 cm
- A bath towel
- Masking tape, to mark lines
- A tape measure, or a long ruler
Steps
- Lean the cardboard on two books to make a ramp on the bare floor.
- Put a strip of masking tape across the ramp near the top: that's your start line.
- Put the car's front wheels on the line and let go. Don't push!
- When it stops, measure from the bottom of the ramp to the front of the car.
- Write the number in your table, then do two more tries from the same line.
- Set the ramp on a carpet the same way and do three tries.
- Lay a folded bath towel flat, set the ramp on it the same way, and do three tries.
- Find the middle distance for each floor and draw a bar 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: Which floor slows a toy car the most?
I changed: Floor I measured: how far the car rolls (cm)
| Floor | Try 1 (cm) | Try 2 (cm) | Try 3 (cm) | Mean |
|---|---|---|---|---|
| Bare floor (tile or wood) | ||||
| Carpet | ||||
| A bath 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 slows a toy car the most?
If I change the floor the car rolls on, then how far the car rolls will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Floor: Bare floor (tile or wood), Carpet, A bath towel | how far the car rolls (cm) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Which floor slows a toy car the most?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor slows a toy car the most?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor slows a toy car the most?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Which floor slows a toy car the most?
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: run all three floors from a 1-book ramp and from a 3-book ramp, and draw a bar for each pair.
Why it works
Where the wheels touch the floor there is friction, a rubbing that slows the car. Rough or soft floors rub more: the wheels sink in a little and have to keep climbing out of the dent, which wastes the car's speed. A smooth, hard floor rubs the least, so the car usually rolls farthest on it.
Going further (7th and up): Change a second thing: run all three floors from a 1-book ramp and from a 3-book ramp, and draw a bar for each pair.
Board layout
- ❓ Question (10 × 8 in): Which floor slows a toy car the most?
- 💭 Hypothesis (10 × 9 in): If I change the floor the car rolls on, then how far the car rolls will ______, because ______.
- 🧺 Materials (10 × 12 in): 6 things: see your list.
- 🪜 Steps (22 × 9 in): 8 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 toy car; Some books; Flat cardboard; A bath towel; Masking tape, to mark lines; A tape measure, or a long ruler.
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 2nd 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 car rolls on and measured how far the car rolls, in cm.
- What did you keep the same, and why does that matter? I kept the same car and the same ramp, 2 books high the same, so the only difference was the floor the car rolls 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 run all three floors from a 1-book ramp and from a 3-book ramp, and draw a bar for each pair.
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.
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