Thursday, January 7, 2010


This activity is very easy. Plants release water in sunlight to cool themselves. This process is called Transpiration.


A sunny day
An outdoor plant/tree with lots of green leaves
A plastic grocery bag (not the ziplock type), preferably see-through, with twist-tie


1. Place a plastic bag over the end of a plant/tree branch with green leaves in bright sunlight.
2. Twist the tie around the base of the bag to keep out air.
3. You can do this to various trees/plants to compare.
4. Predict what will happen.
5. Wait one to two hours.
6. Remove the bag. Observe.


Stomata, which are tiny openings in a leaf, allow gases to enter and leave the plant. They take in carbon dioxide from the air that we breathe out, and use it to make food. They also release oxygen and water. This evaporation of water is called Transpiration. You should see droplets of water inside the plastic bag.