Gases of the air
17
© MDR PUBLISHING 2011 Gases around us Are made of particles These are invisible Consist of……. Nitrogen Oxygen Water Vapour Carbon Dioxide Argon Helium and Hydrogen In the upper atmosphere
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Transcript of Gases of the air
© MDR PUBLISHING 2011
Gases around us
Are made of particles
These are invisible
Consist of…….
Nitrogen
Oxygen
Water Vapour
Carbon Dioxide
Argon
Helium and HydrogenIn the upper atmosphere
© MDR PUBLISHING 2011
The particles in a gas are…
separated by large spaces
free to move
THIS MEANS THAT GASES CAN……
© MDR PUBLISHING 2011
…be poured
…easily change shape
© MDR PUBLISHING 2011
Each tiny particle in a gas has a mass. If you add these up …………….…
A balloon contains 2g of air
1 m3 contains about 1 kg of air
© MDR PUBLISHING 2011
The mass of air pushing down on every m2 of the earth’s surface is huge…
About 10 tonnes / m2
Or 10 elephants standing on each other
SO WHY DOESN’T THE TABLE BREAK?
© MDR PUBLISHING 2011
Because air is a fluid,
Pressure acts in all directions at once
The pressure pushing DOWNIs balanced by
The pressure pushing UP
© MDR PUBLISHING 2011
The air in DRY atmosphere is made from 4 Gases
NITROGEN 78%
OXYGEN 21%
ARGON 0.9 %
Carbon Dioxide 0.03%
© MDR PUBLISHING 2011
NITROGEN 78%
Used help plants grow
© MDR PUBLISHING 2011
OXYGEN 21%
Burns fuels…
Carbohydrates Hydrocarbons
To Produce ENERGY
© MDR PUBLISHING 2011
OXYGEN 21%
Burns fuels…
Carbohydrates Hydrocarbons
To Produce ENERGY
© MDR PUBLISHING 2011
Carbon Dioxide
Has a larger density than air
Is TOXIC for animals
But is used by plants during photosynthesis
To make OXYGEN, SUGARS and STARCHES
Starches
CO2
O2Sugars
© MDR PUBLISHING 2011
It is used …..
In fire extinguishers
In Fizzy drinks
© MDR PUBLISHING 2011
ARGON
Is an INERT gas
Which means it doesn’t react
Used as anartificial
atmosphereIn light bulbs
© MDR PUBLISHING 2011
HELIUM
Is an also an INERT gas
It has a much lower density than air
and so a Helium balloon will float
upwardswhen released
© MDR PUBLISHING 2011
HYDYOGEN
Is a very useful clean fuel
When It burns in Oxygen
It releases a lot of energy
And produces only WATER
© MDR PUBLISHING 2011
The air around us also contains water vapour
The amount of water Vapour is called the HUMIDITY
This changes from place to place
Rain forest Arctic Desert
© MDR PUBLISHING 2011
HUMIDITY
Varies from season to season
It depends on how much water is evaporating into the air
This depends on the CLIMATE
