A puff of air, and the little paper car shoots across the floor. It stops, and the first question comes by itself: "How far did it go?"
A paper car race is a measuring lesson in disguise. Your child compares distances, counts footsteps, reads a ruler and writes numbers down, all to find out which run was the best.
Folding the car in one minute
- Cut a strip of paper about as wide as your hand and as long as the sheet.
- Fold it into three equal parts.
- Stand it up like a little bridge: a flat roof in the middle and a wall at each end.
That is the car. The back wall works as a sail: blow on it and the car slides forward on its two paper edges. Let your child decorate it with a number on the roof, stripes or a driver.
Make one car per player, or share one car and take turns.
The track and the rules
Choose a smooth floor or a long table and stick a strip of tape down as the start line.
- The back wall of the car sits on the start line.
- One puff per run. No second puff once the car is moving.
- The distance is measured from the start line to the front of the car, every time.
- If the car tips over, the run is repeated.
Agreeing on these rules first matters more than it looks. A measurement only means something if everybody measures the same way.
Measuring: from footsteps to a ruler
Take these stages over several days, not all at once.
Just comparing. Put a block where each car stopped. Which block is farther from the line? No numbers are needed yet.
Footsteps. Your child walks from the line to the car, heel against toe, and counts. Then you do the same. Your child counts six steps and you count four. The distance is the same, so why are the numbers different? Let your child work it out: your feet are longer. This small surprise is the reason people agreed on units that are the same for everybody.
A ruler or a tape measure. Put the zero mark on the start line; on many rulers it is not at the very end. With a short ruler, mark where it ends, move it along and add the pieces: 30 and 30 and 18 make 78 centimetres.
Writing the runs down
Three runs each make a fairer race, since one puff is never exactly like another.
| Run | Footsteps | Centimetres |
|---|---|---|
| 1 | 4 | 62 |
| 2 | 6 | 95 |
| 3 | 5 | 78 |
The table is full of questions:
- Which run was the longest? Which was the shortest?
- How much farther did the longest run go than the shortest? (95 − 62 = 33 centimetres)
- How far did the car travel in all three runs together? (235 centimetres)
Before the fourth run, ask for a prediction: "Will it pass 95?"
Changing one thing at a time
Once the race runs smoothly, turn it into a small experiment. Change one thing only and keep everything else the same, otherwise nobody knows what made the difference.
| What you change | Question to ask first |
|---|---|
| A taller back wall | Will a bigger sail carry the car farther? |
| A paper clip on the roof | Does a heavier car go farther or less far? |
| A rug instead of the bare floor | What will the rough surface do? |
| Blowing through a straw | Is a narrow jet of air stronger than a wide puff? |
Your child predicts, runs three times, writes the numbers down and compares them with the earlier table. A wrong prediction is as useful as a right one, as long as it gets checked.
| Rough age | What to try |
|---|---|
| 4–5 | Comparing two stopping points directly; counting footsteps |
| 6–7 | Measuring in whole centimetres; three runs and finding the longest |
| 8–9 | Using a tape measure; working out differences and the total of three runs |
| 10 and up | The average of three runs; changing one thing and comparing the two tables |
Ages are only a rough guide, and every child is different.
In Dologi, "Put in order" puzzles in the Math topic ask children to arrange pencils from shortest to longest. It is the same comparing of lengths, done by eye.
In short
- A folded strip of paper and one puff of air are enough for a race.
- Agree on the rules first: the same start line, one puff, measuring to the front of the car.
- Measure in footsteps, notice that different feet give different numbers, then move on to a ruler.
- Write three runs down, compare them, and change one thing at a time.
Read more: Teaching children to measure: long and short, heavy and light, full and empty