Systematic Error Cannot Be Averaged Away

Lab Brief #2

🎯 Your mission

Run the experiment. Find out what really happens.

⚡ The twist

Nature loves to surprise the careful watcher.

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

systematic error
A consistent bias shifting every reading the same way.
calibration
Checking an instrument against a known standard and correcting it.

Make a hypothesis first

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

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

Get ready

🧰 What you need

balance
known 100 g mass
notebook

⚠️ Safety first

Do not load a balance beyond its stated maximum.

Step 1 of 4 · Read

Think about what you just learned: say what "systematic error" and "calibration" mean in your own words before you start.

Step 2 of 4 · 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 of 4 · Observe

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

Step 4 of 4 · Record

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

Question 1 of 2

Averaging many repeats does NOT reduce:

How sure are you?😐 maybe

Question 2 of 2

A balance reading 2 g high needs:

How sure are you?😐 maybe

Mind = blown

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

Nice work!

You got 0 of 2 right.

Next: Percentage Uncertainty All lessons

🎯

Next Smart Experiment

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

✨ More to explore

🌍 Where you see this in real life: This shows up in your everyday life more than you'd think.

🏆 Stretch challenge (try it 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?”

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Systematic Error Cannot Be Averaged Away

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Systematic Error Cannot Be Averaged Away

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