What is electricity, really?
Picture electricity as water in a pipe. Find out what a battery, a wire and a switch each do.
You flip a switch and a light comes on. But what actually travels through the wire? And why does it need a battery?
Electricity can be hard to picture, because you can't see it. So let's use something you can see: water in pipes.
The water-pipe picture
Imagine a loop of pipe, full of water. Somewhere on the loop is a pump.
- The pump pushes the water round and round.
- The pipe lets the water flow.
- A narrow, bumpy part of the pipe makes the water work hard to get through. That's like a bulb.
- A tap can open or close the loop. That's like a switch.
Now swap the water for electricity:
| In the pipe | In a circuit |
|---|---|
| Pump | Battery |
| Pipe | Wire |
| Narrow, bumpy part | Bulb |
| Tap | Switch |
| Water flowing | Electric current |
The battery pushes tiny charged particles, called electrons, around the loop. They are already in the metal wire. The battery just gets them all moving together, like a crowd shuffling along a corridor. Their movement is the current.
Why does the loop matter?
If there is a gap in the pipe, the water stops. The same is true for electricity. It only flows when there is a complete loop, from one end of the battery, through the wire and the bulb, and back to the other end.
That is why a bulb in Circuit Rescue stays dark until you finish the loop. Break the loop anywhere and the whole thing stops.
A switch is a gap that you can open and close. When it is open, the loop is broken and nothing flows. When it is closed, the loop is complete and the bulb lights up. Every light switch at home works like this.
What makes a bulb glow?
The bulb is the narrow part of the pipe. The electricity has to squeeze through a very thin wire inside it, called a filament. That is hard work, and it makes the filament hot. A hot filament gives off light. (Many modern bulbs use LEDs, which glow in a cleverer way, but the idea of a loop is the same.)
Strong and weak pushes
Batteries come in different strengths. We measure the push of a battery in volts. A normal AA battery is 1.5 volts. In Circuit Rescue every battery is 3 volts.
What if you want a stronger push?
- Put batteries end to end: the plus (+) of one touching the minus (−) of the next. Their pushes add up. Two 3-volt batteries give you 6 volts.
- Put one the wrong way around and the pushes work against each other. They cancel out and nothing happens.
More push means a brighter bulb. But too much push is a problem: the bulb burns out. In the game, a bulb that gets far too much power pops!
What is a short circuit?
Imagine a pump connected to a pipe with no narrow part at all. The water would rush through at top speed, and the pump would have to work extremely hard.
That's a short circuit: a wire that gives electricity a shortcut straight back to the battery, with nothing in the way. The battery gets very hot, very fast. In the game, you see a warning. In real life, short circuits can start fires.
Only experiment with batteries. Never poke anything into a wall socket and never play with mains electricity. It can seriously hurt you. Batteries like AA and AAA are safe to experiment with, but even those get hot if you short-circuit them.
Try it
In Circuit Rescue:
- First light and Flip the switch are about the complete loop.
- Power boost shows what happens when batteries add up.
Next, read how to wire two bulbs, and why the wiring changes how bright they are.