Weight Is a Force, Mass Is Not

Lab Brief #4

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

Nature loves to surprise the careful watcher.

What you'll learn

Mass is the amount of matter and is measured in kilograms. Weight is the pull of gravity on that mass and is measured in newtons. On Earth every kilogram weighs about 10 N; on the Moon it weighs less than 2 N.

Key words

gravitational field strength
The force gravity exerts on each kilogram, about 10 N/kg on Earth.
newton
The unit force is measured in.

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

newton meter
slotted masses
clamp stand
graph paper

⚠️ Safety first

Weight the base of the clamp stand and keep feet clear beneath hanging masses.

Step 1 of 4 · Read

Think about what you just learned: say what "gravitational field strength" and "newton" mean in your own words before you start.

Step 2 of 4 · Do

Hang five known masses from a newton meter and record the reading for each. Plot weight against mass, find the gradient, and use it to predict the weight of a 2.5 kg object.

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

A 3 kg bag on Earth weighs about:

How sure are you?😐 maybe

Question 2 of 2

Taken to the Moon, the bag's mass would be:

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: Gravity Reaches Across Space 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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Weight Is a Force, Mass Is Not

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