7-1: the air around you · 7-1: the air around you •the atmosphere is the envelope, or thin...

7-1: The Air Around You

6th Grade Earth Science


• Weather is the condition of the Earth’s atmosphere at a particular time and place.

What is Weather?


• The atmosphere is the envelope, or thin layer, of gases that surround the Earth.

What is the Atmosphere?


• It contains: nitrogen (78%), oxygen (21%), carbon dioxide, water vapor, and other gases.

What is it made of ?


• Nitrogen molecules (N2) are made of two nitrogen atoms stuck together.

• N2 moves from the air into the soil, into plants, and back into the air – the nitrogen cycle.

Nitrogen (78%)

Complicated !!


• Oxygen molecules (O2) are made of two oxygen atoms stuck together.

• O2 is breathed in by animals – which then produce CO2.

• Plants turn CO2 back into O2 – the oxygen cycle.

Oxygen (21%)


• Fire requires O2 to burn.

• Metal reacts with O2 and creates rust.

• Both of these are called oxidation.


• Sometimes three oxygen atoms combine to make Ozone (O3).

• Ozone blocks harmful radiation from space.


• Carbon Dioxide is one carbon atom and two oxygen atoms (CO2) stuck together.

• Animals breathe it out and plants use it.

• Fire, such as burning gasoline, creates it - as well as volcanoes.

Carbon Dioxide


• O2 and N2 makeup 99% of the atmosphere.

• CO2 and argon makeup most of the other 1%.

The other 1%


• We have discussed dry air so far.

• Air can also be moist, containing H2O – or water.

• This is called water vapor – NOT THE SAME AS STEAM.

Water Vapor


• When there is too much water vapor in the air, water droplets form.

• If they are too heavy, they fall as rain.


• Pure air contains only gas, but real air has particles in it.

• Dust, salt, smoke and other chemicals can be found.

Particles


• The atmosphere is a very important renewable resource.

• We breathe it, it blocks solar radiation, keeps Earth safe from meteors, and allows rain to fall.

Importance of Air


• Pollution is what we call the gases and particles in the air that are not good to breathe in.

• They come from forest fires, soil erosion, dust storms, volcanoes, and plants (spores).

Air Quality


• Most is caused by the burning of fossil fuels.

• Light reacts with pollution and creates photochemical smog – looks brown.

Air Pollution


• This smog irritates eyes, throat, and lungs.

• Light reacts with pollution and creates photochemical smog – looks brown.


• Acid is acidic, but pollution from burning sulfur rich coal, mixed with rain, can make VERY acidic rain.

• This is called acid rain.

Acid Rain


• In the last 30 years, the air has become cleaner.

• But there are still cities where the air is pretty bad.

Air Quality has Improved!!!

7-1: The Air Around You Summary

• The air around us contains many gases, particles, and water.

• We depend on air to keep us alive.

• We are trying to clean the air where there is much pollution – one way by making cleaner cars.

7-1: the air around you · 7-1: the air around you •the atmosphere is the envelope, or thin...

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