Why tree leaves change color in autumn
The student uses the colorimeter to highlight the different pigments present in a tree leaf
Sample protocol for the student
1. Using the colorimeter you will better understand the transformations that take place in a tree leaf at the approach of winter and why they change color
2. Choose several leaves of the same tree and of different colors (green, yellow, red or brown)
3. Using the Colorimeter measurement, observe the color characteristics of the leaves and record them in your notebook.
4. The Colorimeter allows you to know the proportion of the different primary colors (red, green, blue) that make up the observed color.
5. Compare the different values obtained for the color green, what do you see?
6. It is chlorophyll which gives the green color to the leaves. It is necessary for photosynthesis. How does the chlorophyll content in the leaf change?
7. Now compare the different values obtained for the color red, what do you see?
8. Carotenoids give the leaves the yellow, orange and brown colors and are present in the cells during the growing season.
9. Using this information, how can you explain that tree leaves change color in the fall?
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