Why do leaves change color?

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Savannah, GA (WSAV) – It’s fall, y’all! There is one thing that happens every year around this time. We watch the leaves change from green to red.

Do you know why leaves change color? It all comes down to the pigments found inside each leaf. You can find the FULL experiment at the bottom.

SCIENCE: During the spring and summer, we get a lot of sunlight. Plants need that extra sunlight to make chlorophyll. Chlorophyll is the green color found in plants and algae. Chlorophyll helps plants make energy from the sun’s light in a process called photosynthesis.

Once we enter fall, the days get shorter and we get less and less sunlight. This means plants aren’t able to make enough chlorophyll to keep that vibrant green color and the color begins to fade. Yellow, orange, and red colors start to show on leaves.

Leaves actually already have these colors in them because of their different chemicals called pigments. Green has the color Chlorophyll in it, yellow has Xanthophylls, orange has Carotenoids, and red has Anthocyanins. Chlorophyll is much more dominant than the other chemicals that it covers up the chemicals until it breaks down.

Peak fall foliage for the Coastal Empire and Low Country won’t start until the middle of November.

FULL EXPERIMENT: Using Chromatography to separate green and yellow pigments found in different leaves.

Supplies:
Leaves
Glass Cups or Jars
Rubbing Alcohol
Large Bowl
Hot Water
Coffee Filters (cut into thin, long pieces)

Procedure:
1. Cut leaves up into small pieces and put them into the cups or jars.
2. Pour rubbing alcohol into cups; just enough to cover leaves.
3. Use end of a spoon to gently chop and grind the leaves into the alcohol. This will help the chlorophyll start to break down.
4. Cover the cups or jars loosely with a lid, plastic wrap, or aluminum foil.
5. Set cups in a bowl and add hot water to the bowl.
– Be sure to fill bowl with enough water to reach the alcohol level outside the cup.
6. Leaf (ha! get it…leave) the cups to sit for about 1 hour. Swirl glasses every 10 minutes to help mix the leaves and the alcohol together.
– You may need to replace the hot water before the hour is up because the water will cool.
7. Check to see if the alcohol has a green or yellow tint from the leaves. The color should be bright.
– You may need to leave cups in hot water a little bit longer if alcohol isn’t showing color.
8. Take cups out of water and put coffee filter strips into mixture. Leave alone for 30-90 minutes.
9. The tinted alcohol will slowly travel up the paper. As the alcohol evaporates, you will notice the colors traveling at different distances up the filter.
10. Remove filter and place on plate. Allow filter to dry. Colors will show up as it dries.

Chromatography: the separation of a mixture (chlorophyll from the leaves in the alcohol) by passing it as a vapor (rubbing alcohol evaporates up the filter) through a medium (coffee filter) in which the components move at different rates (green and yellow colors show up at different parts of the filter).

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