Battery: a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power.

I inserted a battery into my flashlight so that it would power on and produce light for me to see in the dark.

Complete Circuit: has to be in a complete loop from battery to component, and back to battery again. 

The science class made a complete circuit with wires and a battery to light the light bulb.

Conductors of Electricity: A material through which electric current can pass.

Aluminum and copper are common conductors of electricity since they allow electric currents to pass through them.

Electrical Charge: the physical property of matter that causes it to experience a force when placed in an electromagnetic field.

Water molecules carry an electrical charge and tend to stick to one another.

Electrical Circuit: a path in which electrons from a voltage or current source flow.

Electric fences are designed to create an electrical circuit when touched by a person or animal.

Electrical Current: a flow of electric charge.

When an electrical current was passed through the plastic, the design lit up.

Electrical Insulators: a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field.

Examples of good electrical insulators include glass, paper, and rubber.

Incomplete Circuit: an incomplete electrical circuit in which no current flows.

The students forgot to connect all of the wires, so their work was an incomplete circuit.

Insulator: a substance that does not readily allow the passage of heat or sound.

Birds use these down feathers as a thermal insulator to help them survive in cold weather conditions.

Parallel Circuit: a closed circuit in which the current divides into two or more paths before recombining to complete the circuit.

My mom created a parallel circuit when she plugged in the Christmas lights.