Rubber can come from the sap of a rubber tree. It can also be man-made by using oil from the ground. Rubber can be used to make many objects. Rubber gloves, rubber bands, bouncing balls, bicycle tyres, rain boots and raincoats are all made from rubber.
Rubber was once thought to be a useless material. Natural rubber is sticky when the weather is hot and breaks easily when the weather is cold. Charles Goodyear, a scientist, dedicated his life to finding a solution to the problem. After working hard for more than five years, he finally succeeded in finding a solution to allow rubber to be used in different kinds of weather.
Glass is made from sand. When sand is heated until it is very hot, it melts and becomes clear. The hot melted sand is then poured into moulds to make it into different shapes. When the melted sand cools down, it changes into clear glass. Since we can see through glass, it is used to make glass tanks, window panes, light bulbs and spectacles.