Resistance and Ohm's Law

Lab Brief #3

🎯 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

Resistance is potential difference divided by current, R = V/I, in ohms. For a metallic conductor at constant temperature, current is proportional to potential difference — Ohm's law. Heat the wire and the line curves, because resistance rises with temperature.

Key words

resistance
Opposition to current, R = V/I, measured in ohms.
ohm
The resistance that allows one ampere to flow under one volt.

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

variable low-voltage supply
fixed resistor
filament lamp
ammeter
voltmeter
graph paper

Get ready

⚠️ Safety first

Keep currents small and switch off between readings to avoid overheating.
Low-voltage supply only.

Step 1 of 4 · Read

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

Step 2 of 4 · Do

Vary the supply to a fixed resistor and record current against potential difference for six settings. Plot V against I and take the gradient as resistance. Repeat with a filament lamp and compare the shapes.

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 component carries 0.5 A under 6 V. Its resistance is:

How sure are you?😐 maybe

Question 2 of 2

A filament lamp's V-I graph curves because resistance:

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: Series and Parallel Circuits 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: 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.”

🔌Share card

Share this experiment

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

Resistance and Ohm's Law

Next Smart Experiment

Share this experiment

Resistance and Ohm's Law

Done with science? Try something else

Your Cart (0)