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What Color Are the Leaves Really Turning?

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Everyone loves the beautiful colors of fall, but where do they come from and how does the change in colors happen? In this project, you will uncover the hidden colors of fall by separating plant pigments with paper chromatography. What colors will you see?


Areas of Science
Time Required
Short (2-5 days)
Material Availability
A kit is available from our partner Home Science Tools. See the Materials section for details.
Low ($20 - $50)
Adult supervisions is required while using the stove and hot water. Alcohol is flammable and toxic. Adult supervision is recommended while working with the isopropyl alcohol.
Sara Agee, PhD, Science Buddies
Edited by Svenja Lohner, PhD, Science Buddies
Leaf Chromatography: Explore the Colors of Fall


In this project, you will uncover the changing colors of fall leaves by separating plant pigments with paper chromatography.


Everyone loves the beautiful colors of fall, but where do they come from? What happens to make the leaves turn from green to yellow, orange, and red? Part of the answer is that tree leaves have pigments or colorful molecules, inside them. These pigments make food for the tree during warm, sunny months through the process of photosynthesis. Photosynthesis is when the energy of the sun is absorbed by the plant pigments and turned into glucose, or food energy, which keeps the leaves green. But winter brings colder, shorter days and without as much sunlight, the tree shuts down the food-making leaves for the winter. So what you see in the changing autumn colors is the gradual change of these pigments.

When you look at a leaf, you see the result of all of these colors mixing together. But if you separate the pigment molecules, you can see each individual pigment color on its own. One method for separating mixtures of different components is called paper chromatography. In this method, a mixture (such as your pigment mixture) is applied onto a chromatography paper. The paper strip is dipped into a liquid, called the solvent or mobile phase. The liquid will start traveling up the paper strip and carry all the components within the mixture (such as your different color pigments) along through the chromatography paper. While traveling up the paper, each component interacts with the paper and the solvent differently depending on its chemical properties. Some of them are more attracted to the paper whereas others prefer to stay in the mobile phase. As a result, each individual component travels along the paper at a different speed, as shown in Figure 1. This is how with paper chromatography a colorful mixture of pigment molecules can be separated into each individual pigment component.

Diagram of a homemade paper chromatography testing box

A homemade paper chromatography testing box is made from a tall box with a lid. A dowel spanning the width of the box is placed near the top with a binder clip to hold a paper strip that has been marked by colored pigments. The paper strip is long enough to reach the bottom of the box where there is a small pool of solvent. As the solvent is absorbed by the paper and moves upward, it brings some of the colored pigment markings with it.

Figure 1. Paper chromatography. Molecules are separated from each other, depending on how fast they migrate with the solvent up the chromatography paper. (Wikipedia, 2008.)

You can learn more about paper chromatography in the video below. The video gives an overview of what paper chromatography is, shows how it is done, explains the separation processes involved, and also provides tips and tricks for troubleshooting your experiment.

Introduction to Paper Chromatography | Theory and Practice

In this science project, you will use paper chromatography to separate the colored pigment molecules from fall leaves. By collecting leaves at different stages of turning, you will be able to capture all of the colors of fall. Will you be able to uncover the hidden colors, and tell the full fall story?

Terms and Concepts

To do this type of experiment you should know what the following terms mean. Have an adult help you search the Internet or take you to your local library to find out more.



These resources will give you more information about chromatography and teach you about the types of chromatography used in research labs today:

Materials and Equipment Buy Kit

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materials for color of leaves chromatography project

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Experimental Procedure

Before you start this project, it might be helpful to watch this video. The video goes through all the steps of this project and illustrates how each step is done.

  1. Go on a nice walk with an adult and collect some fresh leaves from different stages of color change during fall. It is best for all of your leaves to come from the same tree, so look for a tree with a variety of leaves at different stages. For the experiment, you ideally want to collect at least 20 leaves of each color. Figure 2 shows an example of some collected leaves:

    Red, green and yellow leaves are picked and piled on top of each other
    Figure 2. Red, green, and yellow leaves collected from a tree in the neighborhood.

  2. Separate and group the leaves into color groups, with 10–30 good leaves in each group (unless you are using a tree with small leaves, like aspen or birch, then you should use a higher number of leaves). Try to form groups from colors that are as different as possible. For example, make a green group, a yellow group, and a red group, as shown in Figure 3. In each group, chose leaves in the deepest colors possible:

    Piles of green, yellow, and red leaves rest on a cutting board
    Figure 3. All leaves are separated into a pile of yellow, red, and green leaves.

  3. Cut the leaves into very small pieces with your scissors (all pieces should be smaller than about ¾ inch long).
  4. For each color, put 10 grams of cut leaves into a glass or jar.

    A mason jar filled with cut green leaves is sitting on a scale. The scale shows 10 grams.
    Figure 4. For each color, 10 grams of cut leaves are placed into a glass.

  5. Add 1 Tbsp. of 90% isopropyl alcohol to each glass.
  6. Using the blunt end of a wooden spoon, macerate (soften) the chopped leaves by squashing them into the isopropyl alcohol at the bottom of the cup.
  7. As you squish the leaves, you will notice that the alcohol will start to turn the color of the leaves. This is called extraction, and the isopropyl alcohol is called the solvent.
  8. Continue until the liquid turns a deep shade of the color of the leaves, about 5 minutes per glass.
  9. Let the macerated suspensions sit for 30 minutes in a dark, room-temperature place to allow the color molecules to fully extract.
  10. Transfer the leaf-alcohol mixture into a resealable plastic bag. Do this for each leaf color separately. Close each bag but leave one end open. Then squeeze on the crushed leaves and collect the leaf extract through the opening of the bag in a small, heat-resistant container.

    A person is holding a small resealable bag on top of a small cup. Inside the bag is a mixture of cut red leaves and isopropyl alcohol. The red leaf extract is pouring from an opening of the bag into the small cup.
    Figure 5. The crushed leaves are placed in a plastic bag and squeezed so the leaf extract can be collected in a small container.

  11. Using a fork, lift out any remaining bits and pieces of leaf material from the leaf extract and set the small containers aside. You should be left with a dark suspension of leafy color in isopropyl alcohol.
  12. Pour some water into a pot and heat it up on the stove. Then switch off the stove and place the three heat resistant glasses with your extracts into the hot water. Let them sit in the hot water for about 20–30 minutes, or until the isopropyl alcohol has mostly evaporated. As the alcohol evaporates, your extracts should become thicker when stirred with a fork.

    Three small cups are inside a pot. Each cup is filled with a different colored solution, green, yellow, and red.
    Figure 6. Three small cups are inside a pot. Each cup is filled with a different colored solution, green, yellow, and red.

    1. Concentrating the extracts should not require more than 30 minutes of evaporating off the isopropyl alcohol, although the extracts will become more concentrated the longer the alcohol is allowed to evaporate off.
    2. Stir each color thoroughly to blend and loosen any bits of dried up pigment from the side of the bowl. Be sure to use a clean fork for each color so you do not mix them!
  13. In the meantime, prepare your chromatography paper. Cut the chromatography paper into strips approximately 2 centimeters (cm) wide by 6.5 cm long. Prepare a total of 6 chromatography strips this way.
    1. Science Buddies Kit: The kit comes with 20 long strips of chromatography paper; two 6.5 cm strips can be cut from each long strip.
  14. Take one of the chromatography strips and use a ruler and pencil to draw a line across it horizontally 1 cm from the bottom. This is the origin line or baseline, see Figure 7 for details. Repeat this step for all 6 of the chromatography strips.
Chromatography strip with a spotted sample at the origin line (1 centimeter from the bottom of the strip)
Figure 7. Draw an origin line (baseline) on the chromatography strip. The leaf extract to be tested will be spotted in the middle of the origin line.
  1. When your color extracts are concentrated enough, use the pipette to place a small dot of extract at the center of the origin line of one chromatography strip as shown in Figure 7. The drop size should be about the size of a pencil eraser. The more extract you have on your paper towel strip the darker the chromatography will be. Some plant pigments can stain, so you should do this on a plate so that the color won't seep through and stain your work surface. Try to apply the extract as smoothly and evenly as you can along the line. Let the spot air dry. Then apply another layer of your sample on the paper strip. Ideally you want to repeat this step 5–10 times to increase the concentration of your sample on the paper. Repeat with 2-3 more strips, using the same color extract, so that you have triplicates for each color pigment.
    1. Use a pencil to label the chromatography strip "red extract, yellow extract, or green extract". Do not use a pen to label the strips: the ink might run when the alcohol passes through the strips.
    2. Allow the spot to dry. If the spot is still very faint, you will need to thicken your extract and repeat step 15 on a new strip.
  2. Repeat step 15 with the other colored extracts so that you have three paper strips for each color extract. Be sure to rinse the pipette between each color extract! Allow the strips to dry.
  3. Using your binder clips, clip two of the prepared chromatography strips to a wooden splint, as shown in Figure 8. Make sure the two strips do not touch each other and that the bottoms align.
  4. Rest the wooden splint on top of the 100 mL beaker so that the strips hang into the beaker and do not touch the sides of the beaker, nor the bottom of the beaker. Estimate the distance between the bottom of the beaker and the end of the chromatography strips.
  5. Remove the wooden splint with the chromatography strips and add 90% isopropyl alcohol to the beaker so the alcohol would just reach the end of the chromatography strips if they are placed back.
  6. Place the wooden splint back on top of the beaker. Do both strips touch the alcohol? The goal is to have the strip just touching the surface of the alcohol, as shown in Figure 8. As long as the alcohol touches the strips and the alcohol level is below the extract dots, you are good to go!
    1. If necessary, remove the paper strips from the beaker and add more 90% isopropyl alcohol to reach the desired alcohol level.
Two paper chromatography strips slowly absorb alcohol from a beaker
Figure 8. Your setup should look similar to this example. The end of the chromatography strip should just touch the alcohol. Note: This picture does not show chromatography strips with plant extract. The colors on your paper strips should look different.
  1. Set the beaker aside and watch as the pigments separate along the length of the strip. As soon as one of the colors reaches the top of a strip, remove the strips and allow them to dry. Depending on the type of paper and the solvent, the separation process can take anywhere between 30 minutes to several hours.
  2. Repeat steps 17 to 21 with all your remaining paper strips.
  3. Compare the colors found in the different strips. What happened to the colors? Did the different groups of leaves have unique colors, or shared colors, or both? Is each color found in the same place along each strip, or in different places? Are the colors in the same order, or in a different order of separation along the strip?
  4. Tip: If you have a pale chromatography, next time try using more leaves, cutting them up into smaller pieces (in step 3), and/or adding more of your colored extract solution onto the pencil line on the chromatography paper (step 15). Alternatively, you can also try to use the extracts themselves as your solvent. Replace the isopropyl alcohol in your beaker with one of the extracts. Then hang the paper strips directly into the extract. Repeat with the other leaf extracts.
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General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "What Color Are the Leaves Really Turning?" Science Buddies, 18 Nov. 2023, https://www.sciencebuddies.org/science-fair-projects/project-ideas/PlantBio_p032/plant-biology/leaves-turn-color-pigments. Accessed 6 Dec. 2023.

APA Style

Science Buddies Staff. (2023, November 18). What Color Are the Leaves Really Turning? Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/PlantBio_p032/plant-biology/leaves-turn-color-pigments

Last edit date: 2023-11-18
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