Do dominoes fall faster when farther apart?
- ✅ Nothing sharp, hot or small
My hypothesis
If I change the gap between the dominoes, then how many seconds the whole line takes to fall will ______, because ______.
You fill in the blanks. Think about how far each domino turns before it hits the next one, and how hard it hits. A guess is a good because: the test finds out.
Change, measure, keep the same
CHANGE
the gap between the dominoes: 1 cm, 2 cm, 3 cm
MEASURE
how many seconds the whole line takes to fall, in seconds
KEEP THE SAME
- 20 dominoes in every line
- the same smooth table
- starting with one finger tip on the first domino
- the same helper working the timer
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
- Dominoes, or small wooden blocks all the same size: 20
- Paper: a sheet
- A tape measure, or a long ruler
- A stopwatch or a kitchen timer
- ✂️ Kid scissors
- 📏 A ruler
Steps
- Cut paper strips 1, 2 and 3 cm wide: they are your spacers.
- Stand 20 dominoes in a line on a smooth table, laying the 1 cm spacer between each pair as you go.
- Slide the spacers out carefully, so that no domino tips.
- Measure the line from the first domino to the last, and write the length down.
- A helper starts the timer when you tip the first domino with one finger, and stops it as the last one falls.
- Write the time in your table. If the line stops early, stand it up again and redo it.
- Do four more tries with the 1 cm gap, tipping the first domino the same way.
- Make the line again with the 2 cm spacer, measure it, and do five tries.
- Make the line with the 3 cm spacer, measure it, and do five tries.
- Find the mean for each gap 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 dominoes fall faster when farther apart?
I changed: Gap between dominoes I measured: how many seconds the whole line takes to fall (seconds)
| Gap between dominoes | Try 1 (seconds) | Try 2 (seconds) | Try 3 (seconds) | Try 4 (seconds) | Try 5 (seconds) | Mean |
|---|---|---|---|---|---|---|
| 1 cm | ||||||
| 2 cm | ||||||
| 3 cm |
MY GRAPH (a line graph: gap between dominoes 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 dominoes fall faster when farther apart?
If I change the gap between the dominoes, then how many seconds the whole line takes to fall will ________________, because _____________________________________________
| I CHANGE | I MEASURE | I KEEP THE SAME |
|---|---|---|
| Gap between dominoes: 1 cm, 2 cm, 3 cm | how many seconds the whole line takes to fall (seconds) |
|
What I think will happen, in my own words:
Name ______________________ Fair day ____________
Question: Do dominoes fall faster when farther apart?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do dominoes fall faster when farther apart?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do dominoes fall faster when farther apart?
| Date | What I did | What I saw | What I think |
|---|---|---|---|
Name ______________________ Fair day ____________
Question: Do dominoes fall faster when farther apart?
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: work out each line's speed (length divided by time) and graph speed against gap. Where does the line stop working?
Why it works
A domino turns as it falls, and when the next one is farther away it hits that one faster and harder. So the wave of falling dominoes usually runs faster when they are farther apart, until they are so far apart that one misses the next. A wider gap also makes a longer line, so divide its length by the time to get the speed.
Going further (7th and up): Change a second thing: work out each line's speed (length divided by time) and graph speed against gap. Where does the line stop working?
Board layout
- ❓ Question (10 × 8 in): Do dominoes fall faster when farther apart?
- 💭 Hypothesis (10 × 9 in): If I change the gap between the dominoes, then how many seconds the whole line takes to fall will ______, because ______.
- 🧺 Materials (10 × 12 in): 4 things: see your list.
- 🪜 Steps (22 × 9 in): 10 steps, three tries at each level.
- 📊 Results (22 × 16 in): Your table (Gap between dominoes 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: Dominoes, or small wooden blocks all the same size; Paper; A tape measure, or a long ruler; 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
| 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: work out each line's speed (length divided by time) and graph speed against gap. Where does the line stop working? |
Every grade this project fits works out a mean. See every project for 4th grade, or print a blank results table.
What a judge will ask
- What did you change, and what did you measure? I changed the gap between the dominoes and measured how many seconds the whole line takes to fall, in seconds.
- What did you keep the same, and why does that matter? I kept 20 dominoes in every line and the same smooth table the same, so the only difference was the gap between the dominoes.
- 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 work out each line's speed (length divided by time) and graph speed against gap. Where does the line stop working?
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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