This is a fantastic lesson to help students understand both phototropism and geotropism. The lesson includes clear definitions and explanations of the two natural phenomena as well as activities for the students to apply their knowledge. The lesson includes lots of clear and helpful diagrams, animations, short video clips (not links, but actually videos) and much, much more! Please check out the preview to get a glimpse of what it's like. It's a great lesson and the accompanying lesson plan is free!