Fuse & Heating Effect is a 3D interactive simulation showing what happens inside a glass cartridge fuse as current increases. Students drag the current slider to watch the fuse wire heat up (grey → orange → white), observe animated electrons flowing through the circuit, and see the wire physically melt and separate when current exceeds the rated value — complete with a flash and spark debris. They can switch between 1 A, 3 A, 5 A and 13 A ratings to explore how fuse selection affects the blow threshold, and toggle the teaching panel for P = I²R annotations throughout.
Classroom Activity — “Which Fuse for Which Appliance?”
Give students this table to complete using the simulation:
| Appliance | Power (W) | Voltage (V) | Calculate I (A) | Correct fuse rating |
|---|---|---|---|---|
| Lamp | 60 W | 230 V | ? | ? |
| Hair dryer | 2000 W | 230 V | ? | ? |
| Phone charger | 18 W | 230 V | ? | ? |
| Kettle | 3000 W | 230 V | ? | ? |
Students use I = P ÷ V to find the current, then set that current on the simulation slider to observe wire behaviour. They then pick the lowest rating that wouldn’t blow under normal use (the correct fuse is always just above the calculated current).
Extension: Ask students to set the current just below the rated value and then switch the fuse to the next rating down — the wire blows. Ask: why do we not just fit a 13 A fuse in everything? This surfaces the key AQA point that a fuse must blow before the appliance wiring overheats, so the rating must be matched to the appliance.