The greenhouse effect

The greenhouse effect is how the earth is heating up due to trapped heat in our atmosphere. 

The atmosphere allows heat to enter but traps it from exiting. This is exactly the same principle of a greenhouse and this is where the name comes from.

Importance of the atmosphere

The atmosphere is important because otherwise our planet would be freezing and life could not exist. 

An example of a planet without an atmosphere would be the moon. The moon varies in temperature hugely everyday, because one of the important functions of our atmosphere is to prevent the temperature changing much per day. 

How does the atmosphere trap heat?

The electrically lopsided (polar) molecules like water can absorb radiation radiation from sun and heat, even though it is not an ion. This is because at any time, one side of the molecule will be positively charged and the other side will negatively charged. 

Polar molecules create an electromagnetic field which vibrates when radiation comes in contact with it. This vibration is kinetic energy, which is felt as heat.

 

Ozone

Ozone is three oxygen atoms bonded together, it can either be “good” or “bad”.

Is ozone good or bad?

Good: Ozone present in the stratosphere absorbs harmful UV radiation, becoming essentially the earth's sunscreen; protecting us from getting skin cancer.

Bad: Ozone present below the atmosphere is harmful to humans, as it is a toxic gas which shouldn't be breathed in.

Ozone layer depletion

This is the gradual thinning of the earths ozone layer in the upper atmosphere.

What causes Ozone layer depletion?

Ozone layer depletion is caused primarily by two different reactions

• Nitrogen oxides react with ozone to form nitrogen and oxygen. 
• Chlorine acts as a catalyst causing ozone to rapidly break down into oxygen

How did CFC's cause the ozone hole?

Chlorofluorocarbons (CFC), found in aerosol sprays, refrigerants and air conditioners break down when they come in contact with the high energy in the upper atmosphere releasing free chlorine ions. These deplete ozones. In fact, this got so bad in the 1980's that there was a huge ozone hole above antarctica. 

They were banned in 1996, when the connection between them and ozone depletion was discovered, now the ozone hole has been filled.

 

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