Pop fuse
How long will the balloon fuse last?
What you need
- balloon
- steel wool
- sticky tape
- 2 wire leads with alligator clips
- 9 V battery
What to do
- Inflate the balloon as much as possible (without popping it) and tie it off.
- From the steel wool, tease out a single thread of wire and tape this piece to the side of the balloon. The wire should lie flat against the balloon, with 3 cm of wire exposed at each end for attaching alligator clips.
- Connect wire leads to each end of the thread of steel wool.
- Hold the other ends of the leads on the opposite terminals of the battery until the balloon pops!
What's happening?
After a while the thread of steel wool warms up enough to make the balloon pop. The explosion breaks the thread and hence breaks the electrical circuit.
When an electrical current passes through a wire, heat is produced as a result of electrical resistance in the wire. An electrical fuse works by breaking the circuit when the current becomes too high. The type of metal in a fuse wire and the thickness of wire will determine how much current the fuse can withstand before breaking due to heat.
