Why do leaves change color in the Fall? During October and November in NYC, we can see beautiful leaves of all different colors: green, orange, yellow, red, and eventually, brown. We did an experiment to investigate these colors, or pigments, in the leaves. You can replicate the experiment at home!
You can watch the video below, click through the Google Slides link for a fun and educational presentation that is great for students at home or in class, view photos from our experiment, and then follow the instructions to try the experiment yourself!
Watch the video
Google Slides Presentation
Check out our Google Slides presentation! Feel free to share with your students at home or in class.
Photos
View photos from the paper chromatography experiment.
Get Inspired!
If you do the experiment at home, we'd love for you to share it with us on social media: tag @grownyc and use the hashtag #GrowNYCEducation
Leaf Color Experiment: Instructions
Objective: Do a paper chromatography experiment to investigate how and why leaves change color in the Fall. Learn about chlorophyll (the green pigment in leaves), and how it breaks down in the cool weather to reveal other, hidden pigments in the leaves: green chlorophylls, yellow xanthophylls, orange carotenoids and red anthocyanins.
Material(s) needed:
Leaves: you can use leaves of fall colors, or green leaves, or spinach leaves, or any plant leaf!
Rubbing alcohol
White paper towels or white coffee filters
Glasses or glass jars, one for each type of leaf you collected
*Note: Because this experiment uses rubbing alcohol, do it with the assistance of an adult and in a well-ventilated room.
Steps:
Collect leaves of different fall colors (or green leaves)
With each leaf, cut it up into small pieces and put it in a glass jar
Cover the leaf pieces with rubbing alcohol (this dissolves the pigments)
Use a spoon to mash the leaves and alcohol
Cover the jars with lids or plastic and let it sit over night.
Cut the coffee filter or paper towels into strips that are one inch wide and about twice as tall as your jars
Place one end of the paper strips into each jar and wait 4-8 hours as the different pigments contained in the leaf crawl up the paper strip.
Conclusion:
You’ve just done chromatography - the process of separating different chemical compounds!
The pigments travel up the paper based on molecule size, and color. Usually, the green pigment of chlorophyll overpowers the other pigments contained in a leaf. In the Fall, the leaf stops producing chlorophyll due to the cooler weather, and that is why we start to see the yellow, orange, and red pigments!
Every week in November 2020, we will post other experiments that you can do at home, as part of our Farmer Scientist Series. Stay tuned for our next experiment!
