85 Bounce! The Wonderful World of Rubber

CHAPTER 1 Rubber, Rubber Everywhere! LOOK AROUND YOU— HOW MANY THINGS CAN YOU SEE THAT ARE MADE WITH RUBBER? YOUR PENCIL ERASER. OF COURSE. BUT WHAT ABOUT YOUR BAG? YOUR SHOES? YOUR COMPUTER? We use rubber in so many different ways, we hardly think about what an amazing material it is. It keeps us warm and dry, and it makes our lives easier, too. It is used to manufacture protective clothing, balloons, kitchen items, sportswear and equipment, tools, and so much more! Rubber makes the games we play more fun and exciting. It gives balls— basketballs, tennis balls, even golf balls— their bounce. Rubber helps us get where we want to go, too, whether by bicycle, car, airplane, or on foot. At first, rubber only came in its natural form, but rubber quickly became so important in our lives that we found a way to make it ourselves. Rubber has a long and interesting history. Europeans first learned of it when explorers came to the New World around 1500.

These Europeans were interested in the sticky substance the native people were using to light their homes, and to make their shoes, toys, and tools. It was brought back to Europe and, over time, other uses were found. When rubbed on paper, for example, it easily erases pencil marks which is why the British still use the word "rubber" for "eraser"! For almost 400 years, the Amazon region of Brazil was the world's main producer of rubber. Then, in 1876, British businessman Henry Wickham took 70,000 rubber-tree seeds from Brazil and secretly transported them to the Royal Botanic Gardens in London. Seedlings were grown, and then rubber plantations were set up in Africa and Asia. People began calling it "Indian rubber," and soon the whole world got used to its convenience. Can you imagine life without it?

CHAPTER 2 Tapping into Rubber's Special Qualities RUBBER DOES NOT COME FROM NATURE IN THE FORM OF BOUNCY BALLS OR BIG BLACK TIRES. Just as blood circulates in the bodies of people and animals, sap circulates in trees. Sap is a liquid that carries sugars and other nutrients to feed different parts of a tree. The sap of rubber trees is called latex. Latex is thick and sticky. It is found inside 10 percent of all flowering plants, including rubber plants. Latex is usually white, though some latex can be yellow, orange, or even red. There are many different species of rubber plants that produce latex, but the Parä rubber tree is the main species used for large-scale latex production.

Parå rubber trees first grew in South America, but as world demand for rubber increased, rubber plantations were developed in other parts of the world. Today, Thailand, Indonesia, and Malaysia are the world's top producers of rubber. To obtain latex, you have to tap the rubber tree. A rubber tapper makes shallow cuts in the bark of a rubber tree. The liquid then begins to drip out, and it is collected in buckets that hang on the trees. The longer latex is in contact with the air, the thicker and stickier it becomes. Eventually the cut in the tree is covered by the latex and the dripping stops. So latex acts as a natural bandage. A tree can be tapped every two or three days in the same general area before tappers have to move to a different place on the tree. It takes about seven years for a used section to heal and become usable again.

Each time a tree is tapped, it will produce about 30 grams of raw latex, adding up to about 11 kilograms a year. After the latex is collected, it is mixed with chemicals to help keep it thin and flowing. Later, acid is added to make the mixture more solid. This mixture is then rolled into big, flat sheets to dry. Drying can be done naturally by placing the sheets in the sun. The rubber sheets can also be dried by placing them in a smokehouse— rather like pizzas in an oven! Inside a smokehouse, smoke surrounds the sheets of rubber, heating and drying them. In forest villages around the world, rubber is still created this way: rolled out by hand, and dried by sunshine or smoke. But today most rubber is produced in industrial laboratories and factories.

Often, as with tires and erasers, the use of rubber is obvious, but there are some uses of rubber that are more surprising. Some medical tools, for example, are dipped in latex. Natural latex is also important as an adhesive in the production of envelopes, labels, sticky tape, and bandages. In fact, rubber is used in factories around the world as a raw material in all kinds of products, from airplanes to zippers. Rubber— or the latex it is made from— may seem like a miracle product, but it can be dangerous. About 4 percent of Americans are allergic to latex. People who are in contact with latex on a regular basis, such as hospital workers and industrial rubber workers, are two to three times more likely to suffer from latex allergies. Just touching a small amount, such as when putting on latex gloves, can cause the skin to become very irritated.