Nov 252019

Do Plants Breathe? Do a simple science experiment with your kids to show respiration in plants. 

respiration in plants science activity

On a winter Sunday afternoon, my daughters and I were taking a stroll in our garden, enjoying the sun. Always ready to pounce on opportunities to make my girls learn something new or be curious about something, I keep myself armed with some questions, interesting trivia or experiment ideas.

That day we were looking at our plants and I was showing them how different each one is. My younger one plucked a Hibiscus flower, and the conscientious older one was upset about Tisha picking flowers! Agreeing that it was wrong to pick flowers, I said, however, “Lets put this flower to good use and do an experiment with it!  Let me pluck few leaves as well!” This is how we embarked on learning about whether plants breathe.

The Question – Do Plants Breathe?

(The answer – Yes, they ‘respire’ through pores on their surface of leaves, petals, etc., and called stomata).

Both the girls knew, in their own ways, that plants are living things. So I remarked to them, “If they are alive, they also probably breathe!” The older one immediately piped in, “Teacher told us that we breathe in oxygen and give out carbon dioxide when we breathe out. The teacher also said that we get oxygen from plants, so we should save them.” The younger one got interested but could not catch on with what the older one said. So all three of us did a couple of deep-breathing exercises right then! (Remember – You need to keep kids interested and engaged and hence try different things, especially if there are two or more age-groups involved).

Now we had established that breathing (we did not venture into ‘respiration vs. breathing’) involved taking in some ‘air’ and then giving out some ‘air’.

I had to now show my children that plants too did this, not through any nose, but through their surface. 

See How Can You Change Color of a Flower

The Experiment – How we Explored the Question in detailed steps

So this is what we did.

Respiration in plants things we need

I requested Pritika to bring a glass bowl from inside the house, reminding her to be careful with the glass. (Although any bowl would do, glass makes it easier to observe things).

I pour water in the bowl and asked the younger one to place leaves in the bowl. I had told her to be careful and not crumple the leaves and place it in the water gently and keeping it horizontal. I pushed it down slightly so that the leaves were submerged in the water.

drop leaves in water respiration of plants science experiments

We then had to leave it alone, without disturbing it, for about an hour. They were both inquisitive and impatient about what was going to happen and kept keeping a watch over the bowl. I was happy – they were gaining some observation skills and building their patience. I did not answer any of their questions because next I wanted them to make more observations and try to infer things themselves.

dip leaves in water respiration activity

In less than an hour, I could see what we were meant to – bubbles on the surface of the submerged leaves, and some bubbles rising to the surface of the water. I did not point this out and waited, hoping they would notice the change themselves. They did! They both saw the bubble as they started rising to the water surface and asked if that was what was supposed to happen. Excited myself, I said, “What could the presence of bubbles mean? If that answers our question about plants breathing, then yes, this is what the experiment was about, otherwise, we have to wait for some other change.”

first bubble proof respiration plants

After a while, I did have to give them a clue – “What are inside bubbles?” “Air!” jumped the older one; grasping the answer at once after that and then she explained it to the younger one. Our day was made and we ended with several more questions? – Will the same thing happen with flowers? Will it happen with all plants? Will it happen with fruits? Will it happen at night as well (this from the older one because the teacher had told them that plants give oxygen during the day)?

appearance of more bubbles respiration in plants

So we repeated the experiment with flowers this time.

flowers breathing experiment dip in water

We could see air bubbles coming out of flowers as well as a proof of respiration.

flowers respiration breathing experiment bubbles in flowers

Science Behind how plants breathe

The petals that were submerged, were still ‘breathing’. When they released the air (breathed out), little bubbles formed on the surface, because the plant was in another medium, water (Is this not a clever way of ‘seeing’ air?!). Since air is lighter than water, the bubbles also rose to the surface of the bowl.

Let me explain a few scientific words related to this context respiration in plants

  • Cellular respiration in plants – respiration in which carbon dioxide is absent is called cellular respiration. Cells respire in this situation.
  • Photosynthesis – the process through which leaves make food on their own is called photosynthesis. The plant uses sunlight, carbon dioxide, water, and minerals to prepare food.
  • Stomata – pores which allow the plant to respire. Through stomata only the leaves are able to take in carbon dioxide and release oxygen.
  • Diffusion – in plants the food prepared by leaves is distributed to all parts of the plant through diffusion where single-cell carries the food to all parts of the plant body.

respiration of plants plants can breath experiment

Word of Caution

Carrying out any experiment with kids needs caution. This experiment is no different. However, let me list the few areas where you need to focus on.

Use a glass bowl for more visibility. But you need to be very careful to let kids deal with them as they may cause damage if they fall down.

Next, with plants, you need to select the right plant that will not cause any toxicity for kids. Not all plants are good hence exercise caution. Don’t let kids pick plants from the garden on their own.

Suitable For

Four-year old pre-school children are exposed to very basic ideas about living and non-living things. Some of them may be taught things like – ‘plants also have life’, ‘plants are helpful for us’, ‘you should not harm plants and flowers’, ‘they “feel pain” too’ etc. It is easier for them to relate to other humans and animals, and even birds. Plants are similar to us in some ways! is too hard a concept for them to grasp. On top of that, they then build their own notions – we breathe through our noses, animals also have noses and breathe through those, plants don’t have noses.

Leave alone four-year-olds, even older children at least up to the age of eight, may not even think of the question of whether plants breathe. Eight-year-old children, i.e. those probably in class 3, would have studied a bit more about differences between living and non-living things, but even they do not really explore this question or become curious about how they breathe if they don’t have noses.

Girls are more inclined towards playing with flowers and plants, hence this activity was thoroughly enjoyed by them. This, however, is a function of how we bring up our children and what they see around them! No stereotype here. Hence, it can be equally interesting and productive with boys.

Final thoughts

I am glad to let you know all these details and now it’s time for you to put this in action with your kids. Feel free to share your comments and also let us know if we missed any details related to this experiment.

We will come back with another experiment soon!


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