Lesson 4 of 10 · Data and Evidence

Experiment⭐ 30 XP

Systematic Error Cannot Be Averaged Away

🧪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

Repeating a measurement reduces random scatter but does nothing to a systematic bias. A balance reading 2 g high reads 2 g high every time, so the mean of a hundred repeats is still 2 g wrong. Only checking the instrument fixes it.

Key Words

Tap a word to see its definition.

Materials Needed

balance
known 100 g mass
notebook

Safety First

Do not load a balance beyond its stated maximum.

Steps

Step 1 — Read

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

Step 2 — Do

Weigh a known 100 g mass on three different balances and record each reading. Identify any balance with a systematic offset, correct it, and re-weigh to confirm the offset is gone.

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

Averaging many repeats does NOT reduce:

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

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