Speed Is a Ratio, Velocity Is a Vector

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

Average speed is distance divided by time. Velocity is displacement divided by time, so it carries a direction. A car going round a roundabout at a steady 30 km/h has constant speed but changing velocity, because its direction keeps changing.

Key words

average speed
Total distance divided by total time taken.
velocity
Displacement divided by time — speed together with a direction.

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

stopwatch
tape measure
cones or markers

⚠️ Safety first

Keep the walking lane clear of obstacles.

Step 1 of 4 · Read

Think about what you just learned: say what "average speed" and "velocity" mean in your own words before you start.

Step 2 of 4 · Do

Time a walker over a measured 20 m in a straight line, three trials. Compute average speed for each. Then walk the same 20 m as a semicircle and compare the speed you calculate from path length with the velocity you calculate from displacement.

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 car travels a circular track at a steady 30 km/h. Which is true?

How sure are you?😐 maybe

Question 2 of 2

A cyclist covers 1,500 m in 300 s. What is the average speed?

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: Acceleration: the Rate Velocity Changes 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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Speed Is a Ratio, Velocity Is a Vector

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