Built around 8th Grade State requirements, this powerpoint goes into how and why seasons happen and how the Earth's tilt affects the seasons in each hemisphere. It does a fantastic job of going step by step through how we determine seasons, why they happen during certain times of the year and where the Sun hits on the Earth. It ends with a link to a video that ties all the concepts together.
The short, concise design allows for students to take quick, yet effective notes and focus on the main ideas instead of "fluff." Great visuals as well to help with understanding!