a basic electrical circuit

Electricity
Electricity is a type of energy that can build up in one place or flow from one place to another. Electricity makes all kinds of machines work. It can have not only great power to move trains but also low power to run mp3 players and calculators.
Most machines you use at home, such as televisions and vacuum cleaners, use “current electricity.” This is the kind of electricity that comes from batteries and power points in your home. There is another kind of electricity, called “static electricity.” You have experienced this when someone “shocks” you after walking across a carpet floor.

A basic electrical circuit
When you flip a light switch on and off, you are closing and opening a circuit. A circuit is the path that electricity follows. For electrons to travel (creating an electric current), the circuit must be closed. When you flip the light switch off, you are opening the circuit and the lights turn off. When you flip the switch on, the circuit it closed and the lights come on. Closing the switch completes a circuit. Electricity flows from one battery terminal, through the wires to the switch and the LED(or load), and back to the other terminal.

LED
What is LED(light emitting diode)?
An electronic device that lights up when electricity is passed through it. When you connect power to LED, you have make sure positive lead(long leg) should connect to positive(+) and negative lead(short leg) should connect to negative(-).