Learning about trees? Complete your photosysthesis science experiment with this simple science demonstration learning how do trees make oxygen. This tree science project teaches the basics of photosynthesis for kids! It’s the perfect addition to your spring STEM activities!
In this tree science experiment, kids can figure out whether some trees give off more oxygen than others.
If kids are completing a NGSS science experiment where they must find a solution to a human-created problem, like ozone damage, then they can conduct this experiment to determine what kind of trees would be best to plant to reverse ozone damage.
Keep reading to find out how to set up your own experiment on how plants breathe.

Related: Science Experiments for Kids
HOW TREES BREATHE
Want to know how trees breathe? Complete this tree science experiment and find out which trees produce the most oxygen through photosynthesis.

Photosynthesis for Kids
How Do Trees Breathe? Science Experiment
This tree science experiment was authored and run entirely by my fourth grader. She wanted to know if she could tell what trees in our yard produced the most oxygen by figuring out which leaves produced the most bubbles in water.
What you need for the tree and oxygen experiment:
- Small containers of similar size (we used mason jars)
- Several types of leaves (we used leaves from three trees and two bushes)
- Timer
What trees produce the most oxygen experiment directions
We modified the classic science experiment where you sink a leaf in water to watch how it produces oxygen. When a leaf is submerged, you can see the oxygen it produces in the form of bubbles clinging to the leaves.
Monkey hypothesized that the more bubbles a leaf produced, the more oxygen it could make. We gathered oak leaves, maple leaves, holly leaves, and two mystery leaves- one from a tree and one from a bush.
We placed the leaves in equal amounts of water (about a cup per leaf). We let the leaves sit in the water for one hour.
After an hour, we observed which leaves had the most bubbles. The maple leaf had the biggest bubbles, but the reddish mystery leaves from the bush had the most bubbles. The holly leaves and the mystery tree leaves had almost no bubbles.

Through this experiment, Monkey determined that planting maple trees and the red-leafed bush would produce the most oxygen in any environment.