Teacher Notes

This module provides information and activities for work on Electricity for Sc4 - Physical Processes - of the National Curriculum Science Orders at Key Stage 2.

Points for further development:

Circuits

The components of a circuit can be connected in series or in parallel. In the former, the components are connected in a row, one after the other. In the latter, components are connected side by side. Examples of series circuits are dynamo driven bicycle lamps and a set of Christmas tree lights. Examples of parallel circuits are the lighting rings and power points of a house.

Cells

A cell is part of a battery that generates electricity. Cells change chemical energy into electrical energy. Adding cells to a circuit generates more potential and increases the current, making bulbs shine more brightly.

Most electric cells contain chemicals which supply the electrical energy. They eventually stop working because of chemical reactions that increase the internal resistance of the cell. The exception is a rechargeable battery, also known as an accumulator, but these too have a finite, if extended life.

Batteries produce direct current (DC) where there is a constant flow of electricity in one direction.

Current

Current is the flow of electricity, so called because people once believed it flowed like water. However, electricity actually flows in "parcels" of electrical charge. Current is measured in amperes or amps. An ammeter is used to measure current. One amp (A) is about 1 million billion electrons per second. Electricity passes through some components with ease. Where components slow down the current, this is known as resistance.

In most electrical appliances, the current used is alternating (AC) where the flow of electricity changes direction.