This is a challenging plotting and graphing exercise, describing how the Earth's Atmosphere evolved from being toxic when first formed to what we have today. The colored graph in the thumbnail is created from a data table. With the first column, 4500 years ago, Formation of the Earth, count up 25 from the bottom for Carbon Dioxide and place a dot. Then, count up 15 spaces from the Carbon Dioxide dot to mark Oceanic Water Vapor. Continue in this way to reach 100% at the top.
 
Then move over to 4000 mya column and mark the gases in the same method. Once you have the dots you carefully connect them, noting which gases disappear or appear and grow over time. Then label and color, and mark the events on the bottom of the graph. Once your students get the hang of it you end up with a really cool, colored graph with major atmospheric changes over time.
 
The discussion questions work well when reviewing the graph in a PowerPoint and discussing how the atmospheric changes relate to the selected events over time.
 
This was used in a college level Historical Geology course but can be easily applied in in other courses dealing with the Earth and its Atmosphere.