7th Grade Students Study Photosynthesis in the Lab

7th graders are currently learning about photosynthesis in science class with Toni Brand. They have been learning about the photosynthetic process, cell respiration, and the way gases move through plant structures and are exchanged with the environment. As part of their investigations, students have been studying Elodea canadensis, an American water weed that is important for lake ecosystems. 

In one lab experiment, students measured carbon dioxide levels in the water surrounding the aquatic Elodea plant using the biological indicator called Bromothymol Blue (BTB). BTB will look blue in water that is low in carbon dioxide, but will turn yellow in water that has a high concentration of carbon dioxide. Students created different environments in 4 test tubes, made predictions, and then compared results the next day. 

In another lab, students studied the structures of aquatic plant leaf specimen to better understand how the structure supports the plant in creating its own food through photosynthesis. Students looked at the structures, colors, and movements of the leaves under the microscope at various levels of magnification, identified chloroplasts, and sketched what they saw. 

The 7th graders will continue their investigation of photosynthesis through both hands-on labs and virtual simulation labs.