Electrical Power and Energy Cost

Lab Brief #5

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

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

What you'll learn

Electrical power is P = VI, and also I²R. Energy used is power times time, and household bills are charged in kilowatt-hours: one kilowatt running for one hour. A 2 kW heater run for three hours uses 6 kWh.

Key words

kilowatt-hour
The energy used by a one-kilowatt device in one hour; the unit on an electricity bill.
electrical power
The rate of energy transfer in a circuit, P = VI.

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

appliance rating plates
electricity meter readings
calculator

Get ready

⚠️ Safety first

Read rating plates only — never open an appliance or a meter cabinet.

Step 1 of 4 · Read

Think about what you just learned: say what "kilowatt-hour" and "electrical power" mean in your own words before you start.

Step 2 of 4 · Do

List six household appliances with their power ratings and estimate daily running hours. Calculate kWh per week for each and rank them, then compare your total with a real meter reading taken a week apart.

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 2 kW heater runs for 3 hours. Energy used is:

How sure are you?😐 maybe

Question 2 of 2

Electrical power is calculated as:

How sure are you?😐 maybe

Mind = blown

🔥 A bolt of lightning is 5 times hotter than the surface of the sun.

Nice work!

You got 0 of 2 right.

Next: Static Electricity 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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Electrical Power and Energy Cost

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