Why do plants grow toward the sun?

Middle School Life Science Lesson:
Energy Transfer and Transformation in Photosynthesis

MS:LS 1-6: Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.

Ultimately, we want students to have a deep understanding of how photosynthesis provides the connection between energy and matter in an ecosystem. Looking at this "Matter & Energy" graphic organizer, it's not going to be easy for students to truly explain this process (though I bet they all think they could!). 

From the set of Crosscutting Concepts Graphic Organizers in 11x17

Breaking the concept apart, however, allows student to focus on the individual components before putting it all together. I built this lesson so that students discover exactly what's going on inside the leaf when it absorbs sunlight. 

(A funny side-story that will serve as caution to you... I find a lot of great digital resources that we use in class. But sometimes this leads me down a path where I forget to do some traditional activities where students really can learn a lot by observing in class. In this case, I was looking for a way for students to see chloroplasts... and spent a half hour looking for the perfect pictures before I had the "Aha!" that we should just find them ourselves in spinach leaves by doing a microscope station! DON'T make the mistake of ignoring those tried and true experiences when you're writing 3D lessons!)

Link to full lesson slideshow with teacher notes

After completion of this lesson (it takes 2-3 class periods), students can begin to fill in the graphic organizer. They will have the inputs on the left and the beginning part of the process. To follow this lesson, students will next learn about glucose and how it's made, and about how carbon dioxide travels into the leaf to become a huge part of the "matter" involved in the process.