Air Pressure1. When air pressure increases, the liquid in a

mercury barometer rises2. An aneroid barometer does not use liquid3. Air pressure is greater at what point B4. Altitude is greater at what point A5. Density of the air is greatest at point B

6. Air pressure – the result of the weight of a column of air pushing down on an area7. Barometer – any instrument that measures air pressure8. Density – the amount of mass in a given volume of air9. Mercury barometer – an instrument that measures air pressure using liquid mercury10. Aneroid barometer – an instrument that measures air pressure without using a liquid11. Altitude – the distance above sea level, elevation

Notes: Earth’s AtmosphereA. Atmosphere – the dome of solids, liquids, and gases that surround the EarthB. The atmosphere has many jobs:

1. absorbs energy from the sun2. recycles water3. works to provide a moderate climate4. protects us from high energy radiation5. protects us from the vacuum of space (a vacuum is a place with NO AIR)

C. Gases in the Atmosphere1. Nitrogen (N) – the most abundant; makes up 78%2. Oxygen (O) – second most abundant; makes up

21%3. Other gases – making up 1% (Argon, Carbon Dioxide, Water vapor and other trace gases)

D. Solids and liquids in the atmosphere:1. dust, salt and pollen2. little droplets of liquid water other than what is in

the cloudsE. Layers of the Atmosphere

1. Lower levelsa. Troposphere –

1. lowest layer2. Earth’s weather occurs here3. contains 90% of the gases that make

up the atmosphere 4. extends to about 10km above Earth’s

surface

b. Stratosphere – 1. from about 10km-50km above Earth’s surface2. upper stratosphere is warmer because of the ozone

layera. Ozone layer – layer of oxygen gas (O3)

b. Absorbs the ultraviolet radiation form the sun

c. energy is converted to heat and warms the air2. Upper Layers of the Atmosphere

a. Mesosphere – 1. middle layer2. outermost level in mesosphere is the coldest (-90C)3. If you have seen a shooting star, you are seeing a meteor

burn up in the mesosphere

b. Thermosphere – 1. 80km above Earth to outer space2. no definite end to Earth’s atmosphere, the gas

and air molecules are spread so far apart that they just blend into outer space

3. air is thin and very hot (1,800C) because energy from the sun hits this layer first

a. The Ionosphere – 1.) lowest layer of the thermosphere2.) energy from the sun causes particles in the

ionosphere to become electrically charged (ions)3.) radio waves bounce off the charged particles

and travel back to Earthb. The Exosphere – 1.) “exo-“ means outer2.) outer layer of the atmosphere3.) satellites orbit in the exosphere