Ozone Layer and the UV Index

The ozone layer quiz

​by

​Science Department

​Often in the news, there is information given about the ozone layer of the Earth and how it needs to be protected and carefully monitored. What exactly is the ozone layer, though? The ozone layer is high up in the Earth's atmosphere, called the stratosphere.

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​​Ozone itself is a gas made up of three types of oxygen molecules. The ozone is formed when sunlight hits certain oxygen molecules and breaks them up into its smaller parts of individual atoms. These individual atoms then join with another type of oxygen molecule to make ozone.

The ozone layer is where there is a high concentration of ozone molecules located high above in the Earth's atmosphere that form when the Sun hits the oxygen molecules.

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​The ozone layer provides protection for the Earth. It protects the Earth from the direct rays of the Sun. Instead of those direct rays reaching the Earth's surface, the molecules in the ozone layer soak up or absorb certain dangerous ultraviolet rays that are the causes of sunburns and skin cancers.​

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​The ozone, and as a result, the ozone layer, can be damaged in a number of ways. First, it must be understood that certain molecules react differently when they come in contact with other molecules. For example, a molecule of sugar mixed with a molecule of water simply makes water taste sweet. This is not dangerous and drinking too much of it may cause cavities, but it is not considered harmful.

​However, there are certain molecules when mixed with ozone molecules, problems begin to occur. There is a chemical reaction that takes place causing the ozone to break apart. When this happens, the ozone can no longer soak up or absorb the ultraviolet light from the rays of the Sun.

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The molecules destroying the ozone are produced on Earth. These are called chlorofluorocarbons or CFCs. They consist of a group of chemicals made up of chlorine, fluorine, carbon, and hydrogen. They were originally used to help keep things cold and were found in air conditioners, refrigerators, and other similar products, as well as in spray cans and fire extinguishers. Many people and scientists assumed they were safe and were great for keeping things cold.​

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​Unfortunately, though, it was discovered the CFCs were harmful to the environment. The chemicals from the CFCs eventually find their way into the Earth's atmosphere, and of course, end up in the ozone layer as well. Once there, they begin to destroy and break apart the ozone molecules, which in turn the layer becomes thinner and weaker. The ozone can no longer soak up or absorb the ultraviolet light from the sun's rays.

​Fortunately, CFCs were banned in the year 2000 after much debate and study by experts and leaders around the world. CFCs are no longer used and have been completely eliminated by most countries. The CFCs that were originally released into the air take a long time to disappear so it will take some time for the ozone layer to be built back up again too. In the meantime, it is important for people to take precautions and use sunscreen and wear sunglasses when spending time in the sunlight.

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In summary, the ozone layer is a protective covering which helps keep some of the Sun's dangerous ultraviolet rays from reaching the Earth's surface. Years ago CFCs, a chemical, was responsible for destroying some of the ozone, but it is now banned throughout the world.

Multiple Choice

How many types of oxygen molecules makes up ozone?

• 1

• 2

• 3

• 4

Multiple Choice

What is the purpose of the ozone layer for the Earth?

• It protects the Earth from the direct rays of the Sun.

• It helps the sunlight reach the Earth's surface.

• It brings needed oxygen to the Earth from the ozone

• It causes sunburn and skin cancer.

Multiple Choice

Ultraviolet rays from the Sun can cause which of the following?

• Sunburn

• Skin cancer

• Both A and B

• Neither A or B

Multiple Choice

Which of the following is the term CFCs an abbreviation for?

• Center for Control

• Chlorofluorocancers

• Cancerous Fluoride Chlorines

• Chlorofluorocarbons

Multiple Choice

All of the following are chemicals that make up CFCs EXCEPT:

• Chlorine

• Fluorine

• Carbon

• Oxygen

Multiple Choice

What happens to the ozone layer when CFCs are introduced into the atmosphere?

• The ozone molecules increase their protection.

• The ozone molecules begin to break down and may be destroyed.

• The ozone molecules are not affected by the CFCs.

• None of the above