Power: How Fast Energy Is Transferred

Lab Brief #5

🎯 Your mission

Predict it first. Then prove yourself right (or wrong).

⚡ The twist

Energy never disappears — it just hides somewhere else.

What you'll learn

Power is energy transferred per second, in watts. A 2,000 W kettle transfers twice as much energy per second as a 1,000 W one, so it boils the same water in half the time and costs the same to do it.

Key words

power
The rate of energy transfer, measured in watts (joules per second).
watt
One joule of energy transferred each second.

Make a hypothesis first

Before you start: which will move faster, and why?

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

Get ready

🧰 What you need

kettle
thermometer
measuring jug
stopwatch

⚠️ Safety first

Hot water scalds — have an adult pour, and never overfill the kettle.
Keep the kettle and its flex well away from the sink.

Step 1 of 4 · Read

Think about what you just learned: say what "power" and "watt" mean in your own words before you start.

Step 2 of 4 · Do

Time how long a kettle takes to raise a measured mass of water by a measured temperature rise. Calculate the energy needed and divide by the time to estimate the kettle's power, then compare with its rating plate.

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 device transfers 6,000 J in 3 s. Its power is:

How sure are you?😐 maybe

Question 2 of 2

A watt is equivalent to:

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.

Next: Efficiency and Useful Output All lessons

🎯

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✨ More to explore

🌍 Where you see this in real life: You use this every time you flip a light switch, ride a bike, or kick a ball.

🏆 Stretch challenge (try it this week): Time how long a small ball rolls down something, then change the slope and try again.

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

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Power: How Fast Energy Is Transferred

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