EXPLORE

Do plants actually breathe?

Activity 1: Plant Respiration – 10 mins

Term to glimpse: Plant respiration

From the School/Home: Any fresh green leaf, transparent bowl

(glass or plastic), water, small magnifying glass (optional)

Vocabulary: Respiration, oxygen, stomata

Procedure A:

1.  Cut a green leaf off a plant (Remember, we need an active/fresh leaf).
2. Place the leaf in the bowl.
3. Fill the bowl with water just enough to submerge the leaf.
4. Keep this bowl outside under the sun for one hour.
5. Record your observation! You should clearly be able to see tiny bubbles around the leaf and the

edges of the bowl! You can also use the magnifying glass to view the bubbles under the leaf

better!

Procedure B:

1. Leave the leaf in the bowl under the sun for several hours more. Do the bubbles increase or decrease?

Procedure C:

1. Take two bowls of water and place a fresh leaf in each one. Place one leaf in a dark area and the

other in sunlight for two hours and then observe how many bubbles each leaf produced.

How does it work?

The bubbles you observed on the leaf and sides of the glass were of oxygen! Leaves take in carbon di oxide and through the process of photosynthesis they create food for the plant. Oxygen is a by- product of this process and goes into the air.

What happens when you hold your breath underwater in the pool and then breath out? You would see bubbles coming up in the water. That’s what happens with plants as well! The leaf is still using the sunlight as part of the photosynthesis process (where leaves convert sunlight to energy). As the leaf creates that energy, it needs to get rid of the items it no longer needs, so it will expel the extra oxygen. Since this oxygen is released underwater, it creates bubbles. And since oxygen is lighter than water, the bubbles will eventually rise to the surface. Hence during the process of photosynthesis, plants also exchange gases through respiration, i.e. they breathe! The exchange of gases occurs via tiny pores on the surface of the leaves called stomata. Stomata is surrounded by guard cells that regulate the size of the stomatal opening. The air we breathe contains 21% oxygen, which is produced by plants. Without plants, we won’t have enough oxygen to live!