Centre of Mass and Stability

Lab Brief #12

🎯 Your mission

Run the experiment. Find out what really happens.

⚡ The twist

Speed isn't the same as force. Don't mix them up.

What you'll learn

The centre of mass is the point where an object's weight acts. An object topples once a vertical line from its centre of mass falls outside its base. Wide bases and low centres of mass are what make racing cars and bus chassis stable.

Key words

centre of mass
The point at which an object's whole weight can be taken to act.
stability
How resistant an object is to toppling when tilted.

Make a hypothesis first

Guess: where does the energy go?

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

Get ready

🧰 What you need

stiff card
clamp stand
string
small mass
cardboard boxes

Get ready

⚠️ Safety first

Keep the clamp stand base weighted so it cannot fall.

Step 1 of 4 · Read

Think about what you just learned: say what "centre of mass" and "stability" mean in your own words before you start.

Step 2 of 4 · Do

Find the centre of mass of an irregular card by hanging it from three different points and marking the plumb line each time. Then tilt a tall box and a short box until each topples and relate the tipping angles to base width and height.

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

An object topples when the vertical line from its centre of mass:

How sure are you?😐 maybe

Question 2 of 2

Which change makes a vehicle more stable?

How sure are you?😐 maybe

Mind = blown

⚡ Static electricity is the same physics as lightning, just smaller.

Nice work!

You got 0 of 2 right.

All lessons

🎯

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✨ More to explore

🌍 Where you see this in real life: This is why airplanes can fly and why rockets reach space.

🏆 Stretch challenge (try it this week): This week, find one thing in your house that turns one kind of energy into another.

👨‍👩‍👧 For the dinner table: “Show me something at home that uses this kind of energy.”

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