Interesting Facts about Oxygen    [01-06-2012] We have to breathe oxygen in order to stay alive. Yes, we cannot live without oxygen! Other animals and plants need it, too. Oxygen plays an essential role in the lives of humans and other living organisms. But how much do you know about it? We cannot see, smell, or touch it. But oxygen exists in the air! The name oxygen was first used by French chemist Antoine Laurent Lavoisier in 1777. Oxygen is essential to human life. In fact, it plays many important roles on Earth. Oxygen is found in the air we breathe and the water we drink (H20). It is an element with the chemical symbol “O” and atomic number 8. Oxygen makes up around 21 percent of the air we breathe. It is also the most common element in the Earth’s crust (around 47 percent) and the third most common element in the universe after the elements hydrogen and helium. Another form of oxygen is Ozone (O3). It is a combination of three oxygen atoms together. The ozone layer in the Earth’s upper atmosphere protects us from dangerous UV light. Oxygen also helps us burn fuels. Oxygen is a very reactive element that easily forms compounds such as oxides. Concentrated oxygen promotes fast combustion. Therefore, you should be very careful when you are near concentrated oxygen. Having it near fuels can be very dangerous. Oxygen has a number of other practical uses. It is used to treat water and smelt metal from ore. Oxygen is also used as an oxidizer for rocket fuel and a number of other industrial, chemical and scientific applications.     출처: 어린이 영자신문 키즈타임즈 (www.kidstimes.net)