Types of Battery There are two main types of battery:
1. A primary cell or battery is one that cannot be recharged once it is used up.
2. A secondary cell or battery can be recharged and used again. Most of the batteries we use today are rechargeable. For example, the battery in your mobile phone has to be recharged.
Although secondary cells usually cost more to buy, they are more cost- effective over time as they can be used again. Rechargeable batteries also benefit the environment as the disposal of batteries contributes to pollution.
Fruit and veg voltage
Fruits and vegetables, such as lemons and potatoes, can be used as a source of chemical energy (a battery) in powering a simple alarm clock. By placing a galvanised nail into one end of a potato and a piece of copper wire in the other, and then connecting to the power terminals of the clock, you will have created a circuit that will allow the clock to work.
Plan, design, carry out and write up an investigation to compare the effects of changing (a) metal types and (b) fruit/vegetable type on the voltage produced across two different metals, when the electrolytes are fruits and/or vegetables.
Fig. 18.6.7 Rechargeable batteries
18.6
Fig. 18.6.8 A potato alarm clock
F Electric eels
can generate potential differences of up to 600 volts for hunting and self-defence – this is nearly three times the voltage supplied to a family home!
