1. Explore. Discover. Understand. Constructing a Model of ppbv of Surface Ozone GLOBE Ozone Protocol Learning Activity

2. Explore. Discover. Understand. Earth’s Atmosphere

3. Explore. Discover. Understand. "The Rest" of Earth's Atmosphere

4. Explore. Discover. Understand. GasPercentageRunning % N2N2 78.084 O2O2 20.94899.032 Ar0.93499.966 CO 2 0.0314*99.9974 He,Ne,Kr,Xe0.0025499.99994 Look at the Numbers Composition of Earth’s Dry Atmosphere (1976 Standard Atmosphere*)

5. Explore. Discover. Understand. Expressing concentration of a gas  parts per billion volume  number density

6. Explore. Discover. Understand. Let’s look at volume of ozone in this classroom Example: Ozone (trace gas) is probably ~ 20 ppbv in this room. This means that ~ 20 billionths of the volume of gas in this room is ozone. Suppose this room is 6 m wide by 9 m long by 3 m high V = 6 m x 9 m x 3 m V = 162 m 3 = 162,000,000 cm 3 = 162 x 10 6 cm 3 So what is the volume of ozone in this room? (20 billionths)(162 million cm 3 ) = (20 x 10 -9 )(162 x 10 6 cm 3 ) = 3.240 cm 3 ~ 3 cm 3 ozone in this room

7. Explore. Discover. Understand. How many molecules of gas in 1 cm 3 ? From ideal gas law, in 1 cm 3 of air at 25°C and 1 atm, there are 2.5 x 10 19 molecules “25 billion billion” molecules in 1 cm 3

8. Explore. Discover. Understand. Let’s look at number density for ozone Example: Ozone (trace gas) is probably ~ 20 ppbv in this room What is number density of ozone (2.5 x 10 19 molecules/cm 3 )(20 x 10 -9 ) =50 x 10 10 molecules ozone/cm 3 =500 x 10 9 molecules ozone/cm 3 or 500 billion molecules ozone/cm 3