For this experiment, we’re going to create an environment where we can actually see the oxygen/carbon dioxide process of leaves!

This activity is really interesting for two reasons: first, kids don’t always think of plants & trees as ‘living’ things so this helps them to visualize that concept and second, it’s a way to actually SEE something that is normally invisible!

1.  Fill a large (preferably glass) bowl with lukewarm water.

2. Find a living leaf (not one from the ground) from a plant you have permission to pick from.

3. Place the leaf in the water and but a small rock on top so it will be fully submerged under the water.

4. Place the bowl in a sunny spot and wait! This may take a few hours.

What you should see is small bubbles form around the the leaf and at the edges of the bowl.

Ask the kids what would happen if they held their breath, went underwater in the pool and then let their breath out — they would see bubbles coming up in the water.

That’s what they are seeing here — the leaf is still using the sunlight as part of the photosynthesis process (where leaves convert sunlight to energy).  As a leaf creates that energy, it needs to get rid of the items it no longer needs so it will expel both water and the oxygen during a process called transpiration.

This is why we see the bubbles — as the leaf gives off oxygen when it is submerged and the oxygen can be seen as bubbles in the water.

And since oxygen is lighter than water, the bubbles will eventually raise to the surface.

Nature Craft from: Adventures with Kids