Here at HTHT, we teach a LOT of science, and the best part about it is feeding young scientists’ curiosity about this amazing world we live in! Although our programs are jam packed with experiments, we make time to let our young scientists ask us whatever questions they’ve always wanted to ask a scientist.
In the coming weeks, we will be sharing a special series of articles answering some of the most frequent questions that come up from our young partners in science. Our question this week is:
WHY DO LEAVES CHANGE COLOR?
Well science friends, the Autumnal Equinox has happened here in the Northern Hemisphere, and that means the beginning of FALL! Fall is a beautiful season, beloved for its cool days and the incredible changing colors of the trees all around us. Why do leaves change colors in fall? Here’s the reason:
Leaf color comes from pigments. Pigments are colored substances produced by leaf cells. The three pigments that color leaves are:
chlorophyll (which produces the green color)
carotenoid(produces yellow, orange, and brown colors)
anthocyanin (produces a red color)
Chlorophyll is the most important of the three. It is the green color in leaves. Leaves contain chlorophyll in order to use the sunlight to produce their own food through the process of photosynthesis.
Carotenoids are organic pigments that are found in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms. Carotenoids create bright yellows and oranges in familiar fruits and vegetables. For example, corn, carrots, and bananas to name a few.
Anthocyanins are pigments that may appear red, purple, or blue depending on the pH. They add the color red to plants, including cranberries, red apples, cherries, strawberries and others.
In the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. Since chlorophyll is no longer needed to make food for the tree, the chlorophyll breaks down. This means the green color disappears, and the yellow to orange colors become visible. Most anthocyanins are produced only in autumn, and only under certain conditions. Not all trees can make anthocyanin, but sugar maples seem to have the easiest time in doing so.
Now you know why leaves change color! Have fun and enjoy the beautiful fall season!
SOURCES AND FURTHER READING:
Resources: State of New York: College of Environmental Science and Forestry: http://www.esf.edu/
Dnr.wi.gov- Environmental Education for Kids: http://dnr.wi.gov/org/caer/ce/eek/veg/trees/treestruecolor.htm