1. Composition of Atmosphere

2. Atmospheric Gases What makes up air in the atmosphere?

3. Atmospheric Gases Air is a mixture of many different gases and each gas has its own properties The composition of air varies from time to time and place to place Never constant

4. Atmospheric Gases Nitrogen Diatomic molecule Backbone of amino acids, the building blocks of protein for all living things

5. Atmospheric Gases Oxygen Diatomic molecule Helps metabolize food into energy and excrete CO 2 Without oxygen you would be brain dead in 5 minutes

6. Atmospheric Gases Argon An inert (non- reactive) gas Released into atmosphere through volcanic activity

7. Atmospheric Gases Carbon Dioxide Exhaled Absorbs heat radiated from Earth, keeps atmosphere warm

8. Atmospheric Gases Other gases: Neon Helium Krypton Hydrogen

9. Other Components There are other components to the atmosphere other than atmospheric gases: Water vapor Dust Ozone

10. Water Vapor Varies 1%-4% Forms precipitation Like carbon dioxide, water absorbs heat energy given off from Earth When do we see this happen?

11. Water Vapor When water changes from one state to another it releases or absorbs heat Energy that drives a lot of storms More details in future units

12. Dust More than dirt – includes pollen, spores and seeds Most commonly found close to the Earth’s surface Why is dust a big deal?

13. Dust Dust acts as a surface where water can condense, forming clouds from which water droplets can grow leading to precipitation

14. Dust Dust’s affects on the atmosphere also includes: Reflection of solar energy Optical phenomena such as red sky at sunset

15. Ozone Ozone consists of 3 oxygen atoms bound together Very little in the atmosphere Absorbs UV radiation Without it Earth would be uninhabitable

16. Comparison In pairs, compare and contrast Earth’s atmosphere to those of other planets using Chrome books

17. Air Density and Temperature Air density – the mass of air molecules per unit volume Which has a greater air density?

18. Air Density and Temperature How does temperature affect air density? Let’s find out!