Design a Way to Move It

Step 1: Something to Notice

Watch first. The explanation comes later.

Watch the idea first — 68 seconds. Then read on, and try it yourself in the next step.

A ball needs to reach a spot on the floor. Too small a push and it stops short. Too big and it shoots past.

How can you make the ball stop exactly where you want it?

Step 2: Find Out

Try a push. If it goes too far, use a smaller one. If it stops short, use a bigger one.

Step 1 — Predict

Your first push sent the ball too far. Which push should you try next?

Choose what you think will happen. You cannot see the experiment until you do — guessing first is what makes it worth watching.

Step 3: So Here Is Why

Now the explanation, after you have seen it happen.

First you make a plan. Then you test it.

Testing tells you

You cannot tell by looking. Try it and watch where it stops.

Then change one thing

Change one thing and try again. One, not two, or you will not know which helped.

Not only your hands

Hands are not the only things that push. A ramp, the wind, a magnet. All of them are forces.

Step 4: A Common Mistake

Lots of people think

“If a plan does not work the first time, it was a bad plan.”

Step 5: Engineers Do This Too

The same idea somewhere new.

People who design cars and bridges test them, find what is wrong, change it, and test again. Nobody gets it right the first time.

A ramp

Step 6: Think It Through

Practice makes it stick.

The Target

Problem 1 of 1

Your ball stopped before the target. Which push should you try next?

Fix the Plan

1 of 4

Put each picture in the right box.

Tap something to move it.

Empty

Empty

2 of 4

You want the ball to stop sooner, but you cannot change your push. Which floor do you use?

3 of 4

Which one moves the ball without anybody touching it?

4 of 4

Put the steps in order.

1Test it
2See what happened
3Change it and test again
4Make a plan

Step 7: Quick Check

Show what you know.

Question 1 of 1

Your first try did not work. What does that mean?

What You Found Out

Make a plan, test it, then change it.
A bigger push goes further. A rougher floor stops it sooner.
Trying again is part of the job.

For the grown-up

Engineers try, then try again — An engineer builds something, tests it, and changes the part that did not work. Getting it wrong the first time is normal. It is how the second try gets better.

Say why your idea should work — Before you build it, say what you think will happen and why. Then you can find out if you were right. That is what makes it science and not just building.