Uniform Circular Motion

Lab Brief #10

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

Nature loves to surprise the careful watcher.

What you'll learn

An object moving in a circle at constant speed is still accelerating, because its direction changes continuously. That acceleration points to the centre and is v²/r, and it requires a centre-directed force — tension, friction or gravity.

Key words

centripetal acceleration
Acceleration directed towards the centre of a circular path, equal to v²/r.
period
The time taken for one complete revolution.

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

rubber bung
strong string
stopwatch
plastic tube

⚠️ Safety first

Do this outdoors or in a large clear space, well away from people and windows.
Check the string for fraying before every trial and wear eye protection.

Step 1 of 4 · Read

Think about what you just learned: say what "centripetal acceleration" and "period" mean in your own words before you start.

Step 2 of 4 · Do

Whirl a rubber bung on a string in a horizontal circle and time twenty revolutions to find the period. Change the radius and repeat. Show that a shorter radius at the same speed needs a noticeably harder pull.

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 in uniform circular motion has:

How sure are you?😐 maybe

Question 2 of 2

Centripetal acceleration is given by:

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: Vectors: Adding Motion in Two Directions 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?”

🏎️Share card

Share this experiment

Send it to a parent who's looking for a 10-minute kitchen science win.

Uniform Circular Motion

Next Smart Experiment

Share this experiment

Uniform Circular Motion

Done with science? Try something else

Your Cart (0)