The Germans were the
first people to celebrate children´s birthdays. Before that, only kings had
birthday celebrations. Maybe that is why we sometimes wear paper crowns at
birthday parties. The ancient Greeks put candles on round cakes to make it
appear like the moon. Nowadays, it is the tradition to put candles on the cake.
The person who is celebrating the birthday, blows out the candles and makes a
wish.
The Ozone Layer
Ozone es a special type of gas; it forms a layer
in the atmosphere that protects us form most of the sun´s ultraviolet light
rays. Too much ultraviolet light can damage our skin. It also affects the
weather and the growth of crops and other plant life. Ozone holes are over the
poles. They are big areas of the atmosphere where the ozone layer is getting
very thin. Scientists discovered that the ozone layer is being destroyed by
chemicals called CFCs. These substances are released into the atmosphere by
some refrigerators and air-conditioning systems, foam packaging such as fast
food cartons, and some sprays
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