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Compare Plants with Human Bodies for Grades 4-6
Materials: Several small mirrors (or use the windows in your classroom), clock with second hand, paper and pencils or pens Instructions: This activity is for students who have learned about transpiration and studied human respiration and circulation of the blood. Ask students to describe human respiration. How does it compare with plant respiration? In-class Writing Assignment: Ask students to write comparisons of human breathing and plant respiration as it occurs during photosynthesis. What is the same and what is different? Comparisons may be either narrative or point-by-point in list form. Do human beings expel moisture as plants do in transpiration? If so, how would you demonstrate or prove it? If students don't come up with the idea, suggest that they use mirrors or window glass -- what happens when you exhale onto a glass surface? How is the moisture in human breath different from the moisture emitted through pores in leaves? Are they the product of similar or different processes? How is blood pumped through the body? How does this compare with the way water is moved through plants? How can we demonstrate that muscles are pumping blood? Suggest that students measure pulse rates before and after exercise—for example, running around the school yard a couple of times. Show them how to find the pulse in their own necks—a little easier than finding the pulse in a wrist. Measure pulse rate by counting for fifteen seconds and then multiplying by four to calculate beats per minute. In-class Math Assignment: Divide students into small groups to measure pulse rates before and after exercise. Have them record their data on the classroom chalkboard. Then have each group determine the average pulse rates before and after exercise for all students in the class—for all subjects in this scientific "study" to determine average pulse rate for fifth (or fourth or sixth) graders. |
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