The Why and How of Leaves Changing Colors

/ / Articles, Blog, Real Science

Fall is such a fun time to homeschool. I well remember when my children were younger, abandoning our homeschooling classroom in favor of a quilt spread out in the backyard. It was fun to feel the fresh air of fall blowing across our faces. As we gazed around at the fall foliage, it was obvious that we have a creative Creator! As if the wonders of one season were not enough, He created four distinct seasons to bring variety to our year! Just when we begin to get a little tired of one, fresh scenery emerges. Whether it’s the sparkling icy crystals in winter, the fresh floral array of spring, the cheery bright sunny days of summer, or the fabulous fall foliage of fall, we can bask in the beauty that each season brings and the Creator who ushers them in. 

Daniel 2:21a  says, “He changes times and seasons…” (ESV)

It’s hard to pick a favorite. They each have their special characteristics, but I believe that fall is an especially unique time when you consider what is taking place inside the tree to create the colors that grace the trees this time of year. The foliage turns from green to an array of red, orange, and yellow hues. 

The why of why it happens could be as simple as because God loves us and wanted us to have variety in our year! But, the how of the process lends itself to an even more amazing explanation that highlights the design of the Designer of it all. 

The leaves are actually the color that they become in the fall! Their true colors are being masked most of the year by the green color of the chlorophyll found in the tree’s leaves. Chlorophyll is a necessary ingredient in the tree’s food recipe along with air, water, and sunlight. Through a process called photosynthesis, the tree gathers these ingredients and prepares a meal of glucose, which keeps the tree growing. 

Just where does the tree find the ingredients for this recipe? Let’s look at each ingredient a little closer.


The first ingredient that a leaf needs in order to make food is chlorophyll, which is already in the leaf. Chlorophyll is green, and there is a lot of it in the leaf! That is what gives the leaf its green color. 

Try This: Go outside and find a green leaf. Place it on a hard surface. Place a piece of white cloth on top of the leaf. Use a large rock to hammer against the cloth. Pick the cloth up, and you should see the green impression of the leaf on the cloth! This is because the chlorophyll seeped out as you pressed the leaf with the rock!


Next, leaves need air. It’s hard to see them with our eyes, but leaves have super tiny holes called stomata that let air in and out. These tiny holes let carbon dioxide air in and release oxygen, a byproduct made during photosynthesis. 

Try This: Fill a bowl with lukewarm water. Pluck a leaf from a tree and place it into the water. Put a small stone on top of it to insure it stays submerged. Leave it for several hours. When you return, observe the leaf, and you should see little air bubbles on the leaf! The bubbles are the oxygen being released through the holes in the leaf’s surface. Those same holes let in carbon dioxide, one of the ingredients plants and trees need to make food.


Another ingredient that all plants and trees need is water! Without water, plants or people wouldn’t survive very long. Plants have straw-like shoots called roots that can dig far into the ground. Not only do the roots anchor the tree into the ground like a sturdy foundation, but they also suck up ground water. Just as you drink juice from a straw, the roots suck up the water the tree needs using the roots, and then tubes throughout the tree or plant carry the water up to the leaves.     

Try This: Pick or purchase a light-colored carnation or a stalk of celery. Provide a glass of water that has been colored with food coloring. Put the stem or stalk into the colored water and leave it for a few days. You should begin to see the flower or leaves from the celery stalk turn the color of the water. This shows how the tubes running throughout the plant carry the water to the leaves for food production. 


A final ingredient in the plant’s food recipe is sunlight. God has provided the sun to light and warm the earth. During the spring and summer months, the days grow longer meaning there is plenty of sunlight during the daytime hours. As summer comes to an end, the days grow shorter, meaning there is less sunlight during the day. You may have noticed that it is still dark when you wake up in the morning and it gets dark well before bed time. When this happens, the chlorophyll in the leaf begins to dry up. Without the green chlorophyll filling the leaf, we begin to see the true color of the leaf: red, yellow, or orange. For a short time during the fall, we are able to see the trees’ true colors! The leaves send every bit of the remaining food to the tree, and then the leaves turn brown and fall to the ground. During the winter months, the tree remains dormant. However, when spring comes and the days once again get longer, the tree wakes up and new leaves begin to grow on the tree.

Try this: Go outside and collect beautiful fall leaves. Glue them to a piece of sturdy paper and laminate at medium heat or use clear contact paper. You can preserve the leaves’ true colors in a festive fall placemat!

About the Author:

Kathy A. Hutto is a degreed educator with over twenty-five years of experience teaching and homeschooling. She has written over two hundred resources for kids and families. Her articles have appeared in Lifeway’s Journey magazines, Lifeway Kids, The Old Schoolhouse® magazines, Christian Living in the Mature Years magazine, and more. She has appeared on popular Podcasts including, Write Where You Are, Women Living Well, Coffee and Bible Time, and Schoolhouse Rocked. She posts free weekly learning videos on your YouTube channel at Her website is

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"Train up a child in the way he should go and when he is old, he will not depart from it" (Proverbs 22:6).