As the saying goes, "Necessisty is the mother of invention." Many times, people invent things to meet their own needs. Later, the solutions to their problems turn out to be great inventions and change our way of life. Two examples will illustrate this point.

When Teng Hung-chi was a vocational school student, he worked as a mechanic in a factory. One day, he was using the bathroom in the factory. His hands were dirty because of work, so he did not want to touch the faucet. He thought, "If I could wash my hands without touching the faucet, it would be great." Teng then worked hard to put this idea into practice. Soon, he invented a faucet controlled by a built-in sensing device. At that time, he was only seventeen. This young inventor later sold the rights to his invention for NT 1.5 million.

Since then, Teng has invented many other things. He represented Taiwan at the IENA exhibition, which is an international exhibition for invention in Gemany. He won first prize three many times. Because of his many great inventions, Teng has become known as "Taiwan's Edison."

Another great modern invention that came from a simple need is the Post-it note. Do you know where its inventor Spencer Silver got the idea for this from? He had been trying to invent a strong glue. As he experimented with different chemicals, he found that he had made a very weak one. He wasn't disappointed, though. Instead, he began to think about how useful a weak glue could be. He tried to convince others in his company of how important his invention might be, but they did not listen.

However, Silver's weak glue enjoyed a great success in 1980-it glued itself to a piece of paper. When Silver's fellow worker Art Fry sang hymns during the church service, he was frustrated that his bookmarks kept falling out of his hymn book. Suddenly, he remembered Silver's invention. Weak glue on a piece of paper would help him mark the right page without damaging the book. Later, he returned to the office and shared his experience with others in the company. Then, the Post-it note was born and successfully spread around the world.