Fall is a beautiful time of year. The changing hues of the leaves on the trees set the color palette for the season. This is a perfect opportunity to ask your kids questions such as, “Why do you think leaves change color?” “What makes leaves green or red or yellow?”
After your discussion, set up a project to teach them about the pigments found in leaves and how they reveal themselves at different times of the year.
Learning About Leaf Pigments
Leaves contain several types of pigments from which they get their color. Chlorophyll is the most common type of pigment found in leaves. This is what gives leaves their green color. Chlorophyll is also essential for photosynthesis, the process that plants use to create the food and energy they need to survive.
Other leaf pigments are cartenoids, which are yellow and orange, and anthocyanins, which are red pigments. In the spring and summer, chlorophyll usually hides the other pigments, but in the fall when the days get shorter and the amount of sunlight is decreased, the chlorophyll breaks down. This is when the other pigments are revealed creating the beautiful fall colors of the leaves.
Related post: Leaf Unit Study Resources
Using Leaf Chromatography To Reveal Pigments
This simple experiment can be used to see all the beautiful pigments leaves possess any time of year. First, you will need some supplies:
- a few leaves (green and other colors if you have them)
- baby food jars
- rubbing alcohol
- coffee filters
- a tray or pan
- very warm water
Here’s the process we used:
- Tear a leaf into little pieces and put it into a baby food jar. We used an assortment of early fall leaves in different colors and stages and put each leaf in a different jar.
- Cover the leaves with an inch of rubbing alcohol.
- Using the end of a wooden spoon, grind the leaves into the alcohol.
- Lightly put the lids back onto the jars.
- Place the jars into a small pan or tray and put 1 inch of hot tap water into the pan.
- Leave the jars in the pan for 30 minutes. Swirl the leaves and alcohol every 5 minutes and add warm water as necessary to keep the temperature up.
- After the 30 minutes is up, the alcohol should be tinted. Place coffee filter strips into the jars so that the tip of the filter just touches the alcohol. Bend the other end over the edge of the jar so the filter strip doesn’t slip.
- Leave the strips in place 30 – 120 minutes. Remove the strips and let them dry. You should be able to see at least one strip of pigment on each strip.
What color is the pigment on the strip? Was there just one color present or more? Does the color on the strip correlate to the color of the original leaf? What pigments do you see?
Do you notice different colors on the strips of different leaves? Where you surprised with your results?
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