Why do the Leaves Change Colour?

​With cooler weather on the way, this experiment is great for understanding how and why leaves change colour in the fall. 

What you’ll need:

• 3 leaves from the same tree
• Rubbing alcohol
• Jar
• Plastic baggie or plastic wrap
• Paper coffee filter
• Small bowl or pan

What to do:

1. First, break the leaves up into tiny little pieces and place them in a jar.
2. Next, pour rubbing alcohol over the leaves until they are just submerged.
3. Now stir and mash the leaves along with the rubbing alcohol. Do this until the alcohol is slightly green. You will want to really stir and mix it around for best results.
4. With a plastic baggie (or plastic wrap), cover the jar and place it in a small bowl or pan and pour hot water into the bowl.
5. Allow the jar to sit in the hot water for 30 minutes (or an hour, if you can!), only stirring the jar every so often. The alcohol should become a very dark green.
6. Next, cut out a strip from your coffee filter. Remove the plastic baggie from your jar, and place the coffee filter into the alcohol and leaf mixture.
7. You will see that the alcohol will travel up through the coffee filter, and as the alcohol evaporates, the colours will begin to separate. For the full effect, you will want to leave the coffee filter in the mixture for about an hour. You can tape it to the edge if that works better.
8. Observe the different colours you see! Whatever colour those leaves change to on the tree, you will see on your coffee filter.

Why does this happen?

• Chlorophyll is what gives leaves their green colour. This green is so bright that it hides all the other colours in the leaves.
• But, in the fall, the chlorophyll breaks down and this is when you can start to see the other colours like red, orange, and yellow come through.
• In this experiment, we used alcohol and hot water (in this case energy) to separate the colours in the leaves.

For more information and pictures, visit: https://www.howweelearn.com/science-experiments-for-kids/.