THE PROPERTIES OF AIR

And other gases: Carbon dioxide, Argon, Ozone The atmosphere is composed of air. Air is made up of a mixture of gases and water vapour. COMPOSITION OF GASES: NITROGEN 78% OXYGEN 21% And other gases: Carbon dioxide, Argon, Ozone

The properties of air are affected by heat from the surface: TEMPERATURE The properties of air are affected by heat from the surface: When air is heated it expands, becomes lighter and rises. The temperature lowers as the air moves further away from surface

TEMPERATURE When it is cooler, the air begins to move back towards the surface This process only occur in the troposphere.

RELATIVE HUMIDITY Is the amount of water vapour that air contains. This is variable Warmer air can hold more water vapour There is a maximum of water vapour If the maximum exceeded the vapour begins to condense and forms clouds.

Atmospheric pressure The gases have weight. This weight presses down on the surface Atmospheric pressure is the weight of the air that presses on the Earth. The atmospheric pressure changes with altitude and temperature

air pressure

The atmosphere and life on Earth Functions of the atmosphere: Protect us from the Sun Provide us with some important gases for Photosynthesis and respiration Build an ozone layer in the stratosphere to protect us from the ultraviolet rays

PROTECTS THE Earth from space objects like meteors (desintegrating them ) Provide important gases for life: Oxygen (O2): respiration Carbon dioxide(CO2): photosynthesis and to maintain the Earth temperature by stopping heat from escaping- NATURAL GREENHOUSE EFFECT.

NATURAL GREENHOUSE EFFECT

Notes Quiz What is the most abundant gas in our atmosphere? 2. What are some trace gases that are in our atmosphere? (name 3)

4. What are some of the solid particles in air? (Name 4) 3. What is ozone? a) It’s liquid oxygen b) It’s an oxygen molecule with 3 atoms of oxygen instead of 2 c) It’s a form of rust 4. What are some of the solid particles in air? (Name 4)

5. Why would there be more water vapour in a tropical rain forest than in a desert? a) the climate is wet in a rain forest and a lot of water would evaporate b) there would be a lot of transpiration from the trees c) both a and b

6. What is air pressure? 7. How is air pressure affected by altitude? 8. Does air have mass? Tell an example where you can see that air has mass.