Today was the start of Unit 6, an introduction to Earth’s Systems. We went through a PowerPoint that reviewed the topics of temperature and density. Students should remember density from 6th grade and should remember temperature from Unit 2. But given how just about all of Earth’s systems are governed by these two factors, it was definitely worth reviewing. After that we talked about effects. What happens when you allow temperature and density to run wild across a planet? Of course these effects include everything from tsunamis to clouds to hurricanes. But I tired to highlight three that will be, for us, particularly relevant during the unit: earthquakes, flooding, and wildfires.