We come across various kinds of rubber products in our life: braided rubber bands, pencil erasers, sports basketballs, soccer balls, sneakers, boots, hoses, tires, bicycle tires and so on.
1. Action of rubber
Their greatest characteristic is their flexibility. People are interested in rubber because of its elasticity. The first bicycles had wooden wheels and were very bumpy to ride. Since the discovery of rubber, people put rubber on the outer edge of the wooden wheel, which makes the bicycle ride much smoother. Later, inflated rubber tires. We walk, we climb, we wear rubber soles. Cars go over mountains, planes take off and land, rubber tires are their shoes. Seventy percent of the world’s rubber is used to make tires. Interestingly, the base of the bridge is also lined with thick rubber support pads, which, together with the rubber products used in daily life, make use of the elasticity of rubber.
2. Home of rubber
The home of rubber is in South America. There grew a kind of rubber tree, which, when cut through its bark, produced white latex, which trickled down drop by drop. The native indians call this latex “tree tears”. They curdled the latex and made it into a ball, singing and dancing in a circle, passing it around. The ball bounces high when it lands. It was their pleasantest game. At that time, indians played with rubber solid balls made of raw rubber. Natural rubber although elastic, but its chain of large molecules like many single spring, scattered pile together, elasticity is not very big, and these springs are easy to open, separation, so the rubber will break, no toughness, a little heat on the hair sticky, soft.