Do Plants Eat? All About Photosynthesis
The sun serves as a source of energy for all living things on Earth.Copyright NASA Goddard Space Flight Center http://umbra.nascom.nasa.gov/images/latest_eit_304.gif
Through a teacher-led discussion, students realize that the food energy plants obtain comes from sunlight via the plant process of photosynthesis. They learn what photosynthesis is, at an age-appropriate level of detail and vocabulary, and then begin to question how we know that photosynthesis occurs, if we cannot see it happening. This prepares students for the associated activity using Elodea, a common water plant suitable to directly observe evidence of photosynthesis. When Elodea is placed in a glass beaker near a good light source, bubbles of oxygen release as products of photosynthesis. By counting the number of bubbles that rise to the surface in a five-minute period, students can compare the photosynthetic activity of Elodea in the presence of high and low light levels.
Students perform data analysis and reverse engineering to understand how photosynthesis works. Both are important aspects of being an engineer.
After this lesson, students should be able to:
- Explain that photosynthesis is a process that plants use to convert light energy into glucose, a source of stored chemical energy for the plant.
- Summarize photosynthesis as a chemical process in which plants use carbon dioxide and water to form glucose and oxygen.