Leaf Chromatography 3rd-5th Grade

Tags: Class Ideas, Fall, Leaves, Outdoor, Indoor, Anytime 

Time : 45 mins 

Author: Vicki DeBusk

ACTIVITY 1: Leaf Chromatography

1. The night or two before your lesson, take one of each of the four different kinds of leaves and cut them up into small pieces making sure to keep them separated from each other.  (keep an example of each leaf to show the class) If you have a mortar and pestle you can grind them down. Put each of the four different leaves into each of the four jars and cover with rubbing alcohol (about 2 tablespoons should work) and let sit overnight. (I heated each jar with the alcohol in the microwave for 15 seconds to help speed up the process)
2. Setup – one type of leaf (one from each of the samples you made the night before) at each table.
3. Ask the class, “What have you noticed about the leaves?  Why do you think they change color? – You can write down predictions if you like.
4. Explain to the class that leaves have different colors (pigments) in them but the green color  – chlorophyll is the strongest and that is why leaves are green.  Chlorophyll reflects green light waves and helps in the process where plants make their own food (glucose) which is called photosynthesis. The other pigments – anthocyanin – reflects red and purple light waves, carotenoid – reflects orange light waves and xanthophyll – reflects yellow light waves.  These other pigments become visible when chlorophyll breaks down and is not produced.  This happens in the fall when the sun is not as high and not as strong and the days are cooler therefore unable to produce chlorophyll.
5. Have the students look at the leaves on their table and see if they can predict which leaf pigment will be present in their leaf. 
6. Pass out the four jars you previously prepared to each table with the corresponding leaf. 
7. Have them place a coffee filter or strip of paper towel in the jar making sure the bottom of the filter or paper reaches the rubbing alcohol.  Observe what happens. – This could take a few hours. (I had students take the jars back to class so they could look at them throughout the day.) We discussed their findings at the following class.

ACTIVITY 2 : Leaf rubbing and poetry writing

1. Have each student grab a leaf and a white piece of paper and make a leaf rubbing using a crayon.  They can do one or many. Have them then write a simple poem or phrase about their leaf using the vocabulary from the lesson or what they learned from the class discussion.

ADDITIONAL ACTIVITIES 

• Leaf symmetry – have students cut a leaf in half, stick onto paper and then draw the other half.
• Walk around the garden and observe the different shapes and sizes of leaves and record them on paper.

Background information:

https://allthatsinteresting.com/why-leaves-change-color