Question: Please can you tell me something about the gases in the air. I am aged 11.
 

Answer: In the air we breathe these are some of the important the gases:

Nitrogen: 78% (78 parts out of a hundred)
Oxygen: 20% (21 parts out of a hundred)
Carbon Dioxide: 0.03% (3 parts out of ten thousand)
Rare Gases (Helium, Argon, Krypton, Neon, Xenon and Radon together make up 0.97%)
Water Vapour (the amount varies)


Nitrogen is important in that it dilutes the oxygen, so you get the right amount. Too much oxygen is almost as dangerous as too little. We use the oxygen to help turn the food we eat into energy, so we can do all the things we do. Without it we would die. Carbon dioxide is important in that it is used by plants in a process called photosynthesis to make food in the form of sugar and starch. So this gas, even though there isn't much of it is essential for life on earth. The amount of water vapour in the air changes from day to day. The air is drier on some days than on others. Without the water vapour in the air, our skin would dry up. Argon is used in filling electron light bulbs and in gas layers and arc welding. Neon is used in lights in advertising displays. Krypton is used in bulbs, sometimes for lighting airfields as it shines through fog better than ordinary light. Xenon is used in lighting in high speed photographic tubes. The most common use of helium is for filling balloons. A form of radon can be used in treatment of tumours. We also find ozone in the air. We get this as a discharge from cars and from an electric spark being passed through oxygen. We also have carbon monoxide from car exhausts. We get sulphur dioxide from anything that generates heat or power from oil or coal containing sulphur.

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