In the article “Do Plants Breathe” published on February 7, we had shared different ideas that children have on the processes of photosynthesis and breathing in plants. Some key questions - Do children understand the difference between photosynthesis and breathing? Do they understand breathing as a process in humans, animals and plants?

Shown in this article is a question that was asked to class 4 children. The data shows that only 42.6% said it was A, ‘making of food’, which is the correct answer. But 52% children have answered B, ‘breathing’. 4% chose options C and D.

Following are some excerpts of student interviews carried out by the EI team in some schools.
Sheena answered A. Her reason was, “Since the sun is present and plants require sunlight to make food, it will be A.”.

Josh answered B. His reason was, “It is breathing because when plants breathe, they take in carbon dioxide and give out oxygen, just the opposite of what happens in animals and humans. The answer can be A, making of food also since the sun is shown in the figure. But taking in carbon dioxide and giving out oxygen is breathing and so the answer is B.”

The interviewer asked the class, “Do plants breathe?”
Salim promptly responded, ‘No, because breathing means taking in oxygen and giving out carbondioxide. Only humans and animals breathe.”

Tanisha added, “I agree. Plants take in carbon dioxide and give out oxygen. This process is not breathing”.
The interviewer further asked, “So do plants use oxygen?”

Lakshmi said, “They do take in oxygen also but they don’t use it. They use only carbon dioxide.”
These are some responses of children which showcase their faulty ideas (i) plants do not breathe, only animals do (ii) plants do breathe but take in carbon dioxide opposite to animals who take in oxygen.

But these are not the only ideas that we have heard about plant breathing. There are many more children who think that photosynthesis happens only in the day and plants breathe only at night. The reason they give for saying this is that plants can ‘take in’ only one gas at a time and so in the day they take in carbon dioxide to make food and in the night they take in oxygen as there is no sun and so they cannot make food. So it seems that they label the process of “taking in” a gas, whether it is carbon dioxide or oxygen as breathing. And it is clearly seen as being different from photosynthesis, a process to make food.

A common reaction to such responses would be ‘Did we teach these things in class? We did not! Then where did they learn all these from?”

A teacher interviewed by the team said, “While teaching we pay more attention to processes like photosynthesis. We think that it is an important process taking place in plants and children should know about it. But when it comes to processes like breathing, though we know that it is a process common to all living organisms, we teach it only in the context of animals and humans saying that they breathe in oxygen and breathe out carbon dioxide.”
“While teaching photosynthesis, we may say that just as animals take in oxygen and give out carbon dioxide during breathing, plants take in carbon dioxide and give out oxygen during photosynthesis.”

“We may be referring to this comparison only as an exchange of gases and how it is different in animals (breathing) and plants (photosynthesis). But if children do not know (because we miss telling them) that plants breathe just like animals and humans when photosynthesis is introduced, the problem begins. They either begin to equate taking in of oxygen (breathing) by animals to that of taking of carbon dioxide (during photosynthesis) of plants, or they begin to think plants don’t breathe because they do not take in oxygen. These become the foundation for misconceptions.”

Sometimes we are not at fault of teaching incorrect things directly. We make certain assumptions while teaching like it is possible for children to make connections on their own. E.g. not mentioning plants while teaching breathing because we feel children will understand, when we say “all living beings breathe”, and that plants are also in this category. Moreover, the use of scientific terms, especially with very young children may lead to a limited understanding of even basic processes like breathing.

It is very important that such assumptions are not made. To do this, once a concept is taught, it is important that we ask children questions ranging from simple definition based to deep conceptual based, to be able to gauge if they have understood the concept entirely and correctly.

Educational Initiatives is an Ahmedabad-based organisation working at the forefront of driving change in education through research, large-scale assessment and the development of new learning technologies. Student responses included are taken from a series of student interviews conducted by EI.

We welcome your ideas on how to prevent misconceptions (mail to: misconceptions.dh@ei-india.com)
Ekta Hattangady, Sridevi Sarkar and Nishchal Shukla
Educational Initiatives