Kaizen Education

Electric charge

Everything is made out of atoms, which are made out of protons, neutrons and electrons. The center of the atom is the nucleus, where it contains the protons and neutrons. The electrons spin around the nucleus.

• Protons have a positive (+) charge.
• Electrons have a negative charge (-) charge
• Neutrons carry no charge (they are neutral)

Overall, the atom is neutral, because the numbers of protons and electrons are always equal.

Electrons sometimes get knocked, rubbed or pulled off an atom. This leaves the atom with more protons than electrons, giving the atom and overall positive charge. This ‘charged atom’ is known as an ion.

In this case it is a positive ion. The electrons that have been removed then attach themselves to another atom nearby. The atom to which they attach themselves will then have more electrons than protons and so will have a negative charge. A negative ion is formed.

Static electricity

Static electricity is the build-up of electric charge on a surface. This build-up of charge most commonly occurs because the surfaec has been rubbed against another surface. Electrons have been rubbed off one surfrace (charging it positive) and have transferred to the other surface (charging it negative).

Current electricity

The electricity you get from a battery or a power point is not static electricity. it is made up of electrons moving along a wire. This movement of charge is called an electric current. These moving electrons pass through things like light bulbs (transforming electrical energy into light), heating elements (into heat) and motors (into movement).

If the electrons don’t move, then no energy is received by the light globe, heater or motor and so nothing happens. It remains ‘off’ .

Simple electronic circuits

Electrons need a path to travel around so that they can deliver their energy. This path is called an electric circuit.

• An energy source, such as a battery, a power point or generator. this supplies the electrons in the wire with the energy they require to get them moving around the circuit
• an energy user, such as a light globes heating element or motor. These devices convert the energy that electrons are delivering to them
• wires to connect everything, making the circuit complete.

Any break in an electric circuit stops the flow of electrons and stops htme from delivering their energy. Most electric circuits have switches that deliberately break the circuit, turning it on or off.

Circuit components

The different parts of a circuit are known as its components. Each component is given a different symbol. This makes diagrams of circuits easier to construct and easier to understand.

Circuit diagrams

A circuit diagram is a simplified and shorthand version of a real circuit. It shows how all the components in the circuit are connected.

A torch is an example of a very simple circuit. Its energy source is a battery and its globe transforms electrical energy into light. The circuit diagram for a torch is shown. the battery supplies the electrons with their energy, which is transformed into light energy and some heat energy. The electrons travel back to the battery, where their energy is replenished.