What Is a Fair Test?

Lab Brief #9

🎯 Your mission

Master the concept. Use it tomorrow.

⚡ The twist

Every solution creates a new problem. That's good — that's the next project.

What you'll learn

A fair test changes only one thing. If you change two things, you will not know which one made the difference.

Key words

Make a hypothesis first

Predict: which design will hold the most weight?

Say your guess out loud — then find out if you were right.

Step 1 of 3 · Read

Look at the new words. Can you say each one?

Step 2 of 3 · Observe

Compare what happened to what you predicted.

Step 3 of 3 · Record

Tell the class one thing you learned today.

Question 1 of 3

In a fair test, how many things do you change?

How sure are you?😐 maybe

Question 2 of 3

Why change only one thing?

How sure are you?😐 maybe

Question 3 of 3

Testing which ball bounces highest, you should drop them from:

How sure are you?😐 maybe

Mind = blown

🌉 The Eiffel Tower can grow 6 inches taller in summer because metal expands when hot.

Nice work!

You got 0 of 3 right.

🎯

We'll pick an experiment that matches exactly how you're thinking right now.

✨ More to explore

🌍 Where you see this in real life: Your phone, your bike, your shoes — all designed with this idea.

🏆 Stretch challenge (try it this week): Build something — anything — out of stuff in your recycling bin.

👨‍👩‍👧 For the dinner table: “What's something around the house you'd redesign — and how?”

Send it to a parent who's looking for a 10-minute kitchen science win.

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