Leaf Science: How to Find the Hidden Colors in Leaves
Do you have a future scientist in your household?
Help your kids discover the science behind nature’s beauty with this fun family experiment.
In this article I’ll show you how to unlock all of the hidden secrets in a leaf through chromatography.
Don’t let the name scare you off, it’s a super-simple science experiment done with items you probably already have around the house.
And it’s a great way to help your kids learn more about the world around us.
It starts out as a nature walk where the kids have a mission—finding different kinds of leaves—so parents can relax and enjoy the lovely fall colors.
Then there’s pounding and noise and actually trying to stain things green. How often are kids allowed, much less encouraged, to do that?
Finally, there’s a science experiment involving chemicals and mysterious migrating colors that appear from nowhere. You’ll see a scientific phenomenon occur right before your eyes!
And it’s all to answer an age-old question that your kids have undoubtedly asked: How do the leaves change color?
Wow! Where do I sign up?
Chromatography is an exciting science activity to do with kids in which you’ll uncover all of the hidden colors that combine to make one leaf. You may be surprised at the results.
In this experiment, you’ll separate the individual shades that make up one color. It’s a fascinating way to see the hidden side of nature, and a good way to get your children to think about the world around them and develop a love for science.
Science experiments encourage kids to be both investigative and reflective. They have to follow instructions carefully and think about their results. Science helps children develop their creative skills and their imaginative skills and teaches them to translate abstract ideas into concrete examples so they can really understand the big stuff.
Science helps create those “Wow!” moments where learning becomes irresistible.
And the best part? It gets your family outside.
Chromatography is inexpensive, easy and good way to help kids identify patterns and understand the world around them. You probably have everything you need already at home.
The leaf project below is a hands-on yet structured activity that will make your kids eager to do more. They’ll want to test the colors of all sorts of things once the mysteries of fall leaves are unveiled.
Let’s get started.
#1: Set Up Your Leaf Laboratory
Prepare for the experiment. Take a few minutes before your leaf-gathering expedition to get the materials ready. That way, the kids will be able to dive right into the science as soon as you return, while their excitement and curiosity are at their peak.
First, find a space for your chromatography experiments. A kitchen, utility room or garage will do fine, especially if the weather turns. You can even do it on the ground as long as the space is fairly level. I set up an outdoor lab on an old table in the backyard.
Set up your jars before the nature walk so they’re ready for use when you get back. Cut the filter into strips to about 1” (2.5 cm) longer than the jars are tall. I tried to set our table up like a proper science lab with beakers of rubbing alcohol, just for some added fun.
Work in a well-ventilated area so there are no hazardous fumes to inhale and minimal risk. It’s worth stressing that chemicals should not go near the mouth and should never be consumed.
Precaution: Please note that working with rubbing alcohol (isopropyl alcohol or ethyl alcohol) and leaves is a flammable process, so be safe!
#2: Enlist Your Budding Botanists
Gather up your colored leaf explorers. Since this experiment starts with a walk and some leaf identification, you can take as many neighborhood kids with you as you can manage.
Whether it’s finding leaves, undertaking experiments or collaborating with friends, you shouldn’t have to look far for willing participants. After one request I had plenty of willing students.
You can make this experiment as complex or as simple as you like just by including a wider range of leaves.
You’ll increase the botany stakes if you include a leaf scavenger hunt to find and identify a range of different leaves. Print a copy of the leaf ID scavenger hunt list (PDF) here. You may need to customize the list with trees found in your area.
#3: Get Out Into Nature
Think ahead and find a place that has a wide variety of trees and leaves. Sometimes even large forests contain mostly the same trees, yet a very small park or even someone’s backyard may have a wider variety.
Arm your little botanists with baskets or plastic bags to gather up leaves. Make sure you have enough containers for each species of leaf they might find. Be sure to keep different types of leaves separate.
Set the target to find at least four different types of leaves. Be sure to include evergreen needles from pines and fir trees as well as fallen leaves. It will be interesting to compare these to the leaves from deciduous trees.
Be prepared for lots of discussion about whether leaves are the same species. And be prepared for questions about leaves that are not part of your treasure hunt.
Keep your eye out for hazards. Collecting leaves might seem simple until you run into a patch of poison ivy or nettles. It’s always a good idea to wear gloves.
You should also categorize the leaves, or at least mark on a map where you found them. There are several websites and apps to help identify trees by their leaves.
Put each type of leaf into different Ziploc bags or baskets and label them as best you can, even if it just says “big tree in Aunt Susan’s garden.”
This is a big part of the scientific process, so it’s pretty important. Categorize and analyze!
#4: Extract the Colors
Return to your ‘lab’ and conduct your experiment. To add some dress-up fun, you can don scientist costumes. Just give the kids safety goggles (or sunglasses) and a lab coat (you can use an extra-large adult t-shirt cut up the front from hem to collar so that it can slide over the arms like a coat).
Pulverize the leaves a little in their separate bags. This will make it easier to get the color out of them in the next step. Use a rolling pin, a mallet or even a rock to bash the leaves inside the bags. This part is lots of fun, but don’t smash them too much.
For extra-tough leaves like holly, you can cut them up with scissors to release the color.
You should prepare a jar or glass for each type of leaf collected. If the kids are old enough, ask them to pour in just enough rubbing alcohol to cover the bottom of the jar.
Remind them to use caution when working with chemicals. It’s only rubbing alcohol and the children are supervised so it’s quite safe, but when you suggest a little element of risk, the experiment becomes much more exciting for the kids!
Watch this video for an example of this chromatography experiment.
Take a strip of filter paper. It should be about an inch (2.5 cm) longer than the height of the jar. Press the crushed leaf about ½” (1 cm) from the bottom of the strip to make a narrow stripe of green on the white paper. Press firmly until the pigment is transferred onto the filter paper. You really want to smash the leaf guts into the paper!
Ask the kids to observe what color was transferred to the strip. It will be interesting to compare to the results later.
Once there’s plenty of leaf matter on the bottom of the filter paper, fold the paper over the side of a jar so that the bottom of the strip is barely touching the rubbing alcohol. You can use Scotch tape to secure the filter paper, if necessary.
#5: Separate the Pigments
Leave the filter paper to absorb the color for 30-90 minutes. You should see small bands of color moving up the filter paper and separating out as they go. This takes between 30 and 90 minutes depending on conditions, so be patient!
When the color seems like it’s moved as far as it’s going to go, lift the filter paper out of the solution and leave it to dry out for a short period. Then you can document your results.
Watch this video for a good description of the chemicals in the leaves that you’ll see on your strip. In the video, she uses a different method for transferring the colors, but the results are the same.
What colors did your family find? How do they compare to the color you started with? Do you see green? Orange? Red? Even green leaves may have orange, yellow or red inside that ‘magically’ appears during the experiment.
Some Final Thoughts…
Chromatography is a great way to get the best from all of the bright leaves this fall and help your kids understand the world around them in a simple, visual way.
We had a ball on our botanical treasure hunt and then lots of fun with our experiments. I hope your family did, too. My kids could hardly contain themselves from racing round the house and garden finding other things to experiment with. And they’re right.
You can do this experiment with candy (like Skittles), food dye and even flowers. Even marker pens can give hours of science fun!
If your kids loved chromatography, take color experimentation a step further. Use flowers and herbs used in the dyeing process like tansy, woad and pomegranate peel to dye wool or cotton in natural ways and see what happens.
I told you science was cool!
What do you think? Have you ever tried chromatography? What did your family discover? Did you have any interesting reactions? Leave your comments and photos of the colors you found in the box below.
Emma is a teacher, educational consultant and writer living in southwest France. She writes on a range of educational and lifestyle themes. Other posts by Emma-Jane Lee »