Earths Atmosphere

1
Earths Atmosphere

• Lesson 1

2
Think About it.

• You have lived in air all your life. Write 5
  facts about air that you already know.
• 1.
• 2.
• 3.
• 4.
• 5.

3
Demonstration 1

• Observations
• Data
• Inference

4
Demonstration 1

• Observations stretchy balloon, has a little bit
  of air in it
• Data Mass of balloon empty ______ g
• Mass of balloon with air _______g
• Inference Air is matter. It has mass and
  volume.

5
Demonstration 2

• Observations
• Data
• Inference

6
Demonstration 2

• Observations Empty clear cup filled with water,
  covered with cardboard and inverted
• Data water remained in the cup
• Inference Air exerts pressure in all directions,
  even up

7
Demonstration 3

• Observations
• Data
• Inference

8
Demonstration 3

• Observations Warm water poured into a two-liter
  bottle and bottle closed and set in ice
• Data bottle began to collapse
• Inference Air pressure was lower inside the
  bottle than outside

9
Demonstration 4

• Observations
• Data
• Inference

10
Demonstration 4

• Observations Beaker with water and a cork on
  surface, cup inverted and lowered into water
• Data level of water in cup lower than beaker
• Inference air takes up space and cannot occupy
  the same space as other matter

11
Demonstration 5

• Observations
• Data
• Inference

12
Demonstration 5

• Observations burning candle in water, inverted
  flask over the candle with mouth in the water
• Data candle went out, water rose in the flask
• Inference oxygen used by burning made space and
  the pressure outside pushed the water into the
  flask

13
Notes

• 1. Air is composed of gases that are invisible.
• 2. Air exerts pressure in all directions.
• a. Air pushes on the side of the balloon.
• b. Air pressure can collapse a bottle.
• c. Air is strong enough to hold up water against
  the force of gravity.
• 3. Air has mass.

14
Notes, cont

• 4. Air is a mixture of gases.
• 5. Air pressure changes with altitude.
• As you move away from surface of earth, the air
  pressure decreases because there are fewer
  molecules pressing down.

15
Final Demonstration

• Make a prediction
• Observations
• Explanation

16
Warm Up

• Define atmosphere.
• What does the word altitude mean?

17
Gases in Our Atmosphere

• Nitrogen - 78 - inert gas, dilutes the
  reactiveness of oxygen
• Oxygen - 20 - produced by photosynthesis, used
  in breathing, very active in rusting and burning
  reactions
• Argon - 0.93 - inert gas, made from volcanic
  eruptions

18
Gases in Our Atmosphere, cont

• Carbon Dioxide - 0.03 - used in photosynthesis,
  created in breathing, greenhouse gas
• Water Vapor - varies between 0 - 5 - clouds,
  precipitation, greenhouse gas
• Methane - trace amounts - greenhouse gas,
  produced in decay