Batteries and the like

1. State why batteries should not be dumped carelessly.
- A battery is made of layers of poisonous chemicals inside a metal “can”. When batteries are disposed of carelessly, the chemicals will leak out and cause harm. These chemicals more often than not seep into the ground in these cases and cause land pollution.

2. Explain why :

a) Some materials carry electricity while others don’t
- In many materials, the electrons are tightly bound to the atoms. Wood, glass, plastic, ceramic, air, cotton etc. are all materials that do not carry electricity well. This is because the electrons don't. These materials are insulators. However, most metals have electrons that can detach from their atoms and move around, called free electrons. Gold, silver, copper, aluminum, iron, etc., all have free electrons. The loose electrons make it easy for electricity to flow through these materials, so they are known as conductors.


b) You see lightning in a storm before you hear thunder.
- The flash of a lightning strike and the resulting thunder occur at roughly the same time. However, light travels at 186,000 miles in a second, almost a million times the speed of sound. Sound travels at the slower speed of one fifth of a mile in the same time. So, therefore the flash of lightning is seen before the thunder is heard.

c) A light switch has to be turned on before the light comes on
- A light switch operates a switch in a circuit. When the light switch is turned on, the switch goes down and completes the circuit, allowing electricity to flow through it. When the light switch is not switched on, the circuit is not complete and the light will not work.