Make Your Own Electricity
Ask the children what makes the following work: ordinary torch, overhead light, computer, mobile phone charger, radio. They should easily identify electricity (mains or battery).
Tell the children that they are going to find out about electrical items that work without mains or battery electricity. Ask them to read the information and then look at the pictures. Explain the term ‘generator’ (a machine for producing electricity through energy from movement) and that something has to provide this energy. After they have completed the sentences on the worksheet, invite volunteers to explain where the energy comes from to produce electricity for each item. For the wind-up items, point out that the person turning the handle or the pedals provides the energy.
As a homework activity the children could find out about other electrical items that provide their own electricity, such as solar-powered calculators and road signs.
The extension activity on the worksheet provides an opportunity for fair testing. Ask the children to plan their investigation before they begin, making sure that the test is fair for comparing a hand generator with a bulb. The brightness of a bulb can be measured by using a photo-sensor and data logging software, or by holding a number of sheets of paper in front of it as described on worksheet 2.06: Voltage value.