Lesson 5 of 10 · Data and Evidence

Experiment⭐ 30 XP

Percentage Uncertainty

🧪Lab Brief #5

Data and Evidence.

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

Nature loves to surprise the careful watcher.

🤯

Mind = Blown

🔬 The more you look, the more nature shows you.

🔮

Make a hypothesis first

Before you start: write down what you think will happen, and why.

What You'll Learn

Absolute uncertainty is the ± on a measurement; percentage uncertainty is that divided by the measurement, times 100. The same ±1 mm matters far more on a 5 mm length than on a 500 mm one, which is why measuring a bigger sample improves precision.

Key Words

Tap a word to see its definition.

Materials Needed

ream of paper
ruler with millimetre divisions
calculator

Safety First

Have an adult check your set-up before you start, and tidy everything away afterwards.

Steps

Step 1 — Read

Read the explanation above and note the two key terms before you start.

Step 2 — Do

Measure the thickness of one sheet of paper directly, then measure 200 sheets and divide. Calculate percentage uncertainty for both methods and explain which is better and why.

Step 3 — Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 — Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Check Your Understanding

Question 1

1 of 2

A measurement of 50 mm ± 1 mm has a percentage uncertainty of:

How sure are you going to be?😐 maybe

🌍

Where you see this in real life

This shows up in your everyday life more than you'd think.

🏆

Stretch Challenge

Try this in real life this week.

Try one experiment in real life this week — even a tiny one.

👨‍👩‍👧

For the dinner table

“What's the most surprising thing you learned today?”

🎯

Next Smart Experiment

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

🦠Share card

Share this experiment

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

Back

Ready?