Lesson 4 of 9 · Data and Evidence

Experiment⭐ 30 XP

Repeats, Means and Reliability

🧪Lab Brief #4

Data and Evidence.

🎯 Your mission

Predict it first. Then prove yourself right (or wrong).

⚡ The twist

Nature loves to surprise the careful watcher.

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Mind = Blown

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

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Make a hypothesis first

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

What You'll Learn

One measurement can be wrong by accident. Taking three or more repeats and using the mean reduces the effect of random scatter, and comparing the repeats tells you how much to trust the mean.

Key Words

Tap a word to see its definition.

Materials Needed

paper
scissors
paper clips
stopwatch
metre rule

Safety First

Use scissors carefully and cut on a flat surface.
Drop from a stable step with someone spotting, never from a chair.

Steps

Step 1 — Read

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

Step 2 — Do

Time how long a paper spinner takes to fall, five times. Calculate the mean and the range. Then do it once only and explain to a partner why the single value is less trustworthy.

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

Taking repeats and averaging mainly reduces:

How sure are you going to be?😐 maybe

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Where you see this in real life

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

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Stretch Challenge

Try this in real life this week.

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

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For the dinner table

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

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Next Smart Experiment

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

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