Lesson 7 of 7 · Electricity
Experiment⭐ 30 XP⚡ Spark LabCircuit Safety: Fuses, Earthing and the Ring Main
Electricity.
🎯 Your mission
Run the experiment. Find out what really happens.
⚡ The twist
The opposite of what you expect is often what happens.
Mind = Blown
🎢 You feel weightless on a roller coaster because you and the seat are falling at the same speed.
Make a hypothesis first
Predict: what happens if you double the force?
What You'll Learn
A fuse melts if current exceeds its rating, breaking the circuit before cables overheat. The earth wire gives fault current a safe path and holds an appliance's metal case at zero volts. Residual current devices go further, cutting power within milliseconds of an imbalance.
Key Words
Tap a word to see its definition.
Materials Needed
- demonstration plug (not connected)
- fuse samples
- calculator
Safety First
- Use a demonstration plug only — never open a plug that has been connected to mains.
- An adult must supervise.
Steps
Read the explanation above and note the two key terms before you start.
Examine a cut-away plug and identify live, neutral and earth by colour. Given four appliances with stated powers on a 230 V supply, calculate the current each draws and select a 3 A or 13 A fuse for each.
Record what actually happened, including anything that did not match what you expected.
Write a conclusion that answers the question this lesson opened with, and state your uncertainty.
Check Your Understanding
Question 1
1 of 2A fuse protects a circuit by:
Where you see this in real life
This is why airplanes can fly and why rockets reach space.
Stretch Challenge
Try this in real life this week.
This week, find one thing in your house that turns one kind of energy into another.
For the dinner table
“Show me something at home that uses this kind of energy.”
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Circuit Safety: Fuses, Earthing and the Ring Main
Run the experiment. Find out what really happens.
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