What are Tires Made out of?
Think of all the different things that can be made from rubber.
There are gloves, rubber bands, boots and shoes, fan belts for cars, inflatable boats, bottle stoppers, balls, tires, and foam mattresses.
The rubber used to make each of these items is different.
Some rubber is light and spongy, some stretchy, and some hard and stiff. Imagine a mattress made from the rubber in a bottle stopper.
It would be very uncomfortable.
Natural rubber is made from a white liquid called latex. It is the sap which comes from rubber trees.
A V shape is cut in the bark of the tree. The sticky, white latex oozes from the cut and is collected in small cups tied to the tree trunk.
Latex is made of long chains of carbon and hydrogen atoms joined together.
These are called hydrocarbons.
The long hydrocarbons can easily slide past each other while latex is a liquid.
To make latex into a useful, springy solid, it is heated with a substance called sulfur.
The sulfur atoms make bridges between the hydrocarbons and lock them together.
This type of rubber, called vulcanized rubber, is very tough. It is used to make tires.
Scientists are able to take hydrocarbons, and many other basic building blocks of matter, and rearrange them to make new materials.
By changing the pattern of the atoms in natural materials, scientists can make artificial materials.
They can make materials stronger, stiffer, softer, or more elastic.