Educational research
This work was realized during my PGCE (post-graduate certificate in education) course, when I was teaching in English secondary schools. The title of this research is:
Misconceptions in science education
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Having acquired this information, I decided to investigate further on the misconceptions that remained with the students all the way to year 11. Those were the ones involving the concepts of force and particles. There were also problems with photosynthesis: many pupils didn't have clear that the plant respires all the time and photosynthesises during the day. Furthermore, a lot of students didn’t know that plant biomass comes from the air.
I developed a questioning to investigate these issues. In the end , I interviewed some university students, to find out if they still have some of these misconceptions. I have found that they do.
-Particle model
Having started my research, I realized that some of the questions were very easy to the majority of the students interviewed, while others caused more controversy and they needed to be given more thought. I decided to explore these questions further and, instead of just asking if the space between particles was full of air, I developed a questioning:
Is there anything between particles? What is it? Air was the common answer, but other things came up as well: oxygen, nitrogen and others.
Interestingly, pupils often were puzzled by the questions and they hesitated before saying anything. Then they said “I don’t know” or “some other gas”. Very few students seemed to have incorporated the concept of vacuum or empty space.
Here I show some examples of interviews I had with Y9 top set pupils:
Pupil 1
You know that the particles in a solid are close together and that the particles in a gas are far apart from each other, don’t you? – Yes- So, why is that? Why are the particles of a gas so far apart from each other? - Because of energy. – What about it? - They have more energy. –Ah! Good! What type of energy? –Kinetic energy. – Excellent! Thanks.
It makes me wonder why not a single person answered that particles are kept apart because they move at high speeds, although some recognised that kinetic energy is the key idea. Sometimes I felt that Some [pupils answered energy without really having the image of the particles moving at high speeds.
Pupil 2
Is there anything in between the particles? – Good question! Humm...I don’t know. _ Hum… forces? – Yes , there are forces , but a force is not a thing (curiously, in the context of the quantum theory of field, the forces are exerted by other type of particles that are exchanged between the particles of the gas,but that is not the case here). - I don’t know
Pupil 3
Why are particles in a gas away from each other?- I don’t know. Ah! Energy!-What sort of energy? – Kinetic-Good. –What is there in between the particles? -Nothing- Pupil 2 says: you cannot have nothing, there must be some other particle there- Pupil 3 says : It is vacuum.- Pupil 2: you cannot have vacuum - Pupil 3: - Yes, you can. That is what you get in space.- RO:- Yes, excellent. Most of the universe consists of vacuum, which is an area of space without any particles at all.
Why are the particles away from each other?
Some bright pupils couldn’t answer that. One said that it is because there is no attraction between the particles and another pupil said that it is because the particles repel each other.
Very few of the students interviewed mentioned that empty space is found on space, but others (Y9 top set) couldn’t conceive an absolute emptiness:
-Plants and photosynthesisThe questioning about where the plants take their biomass from extended to even more basic concepts like energy and particles. Some students answered that the mass comes from photosynthesis, and I had to ask some more questions to make sure that there was understanding there:
Is a tree made of particles as well? –Yes.-Right,but can you explain where the particles that make up a tree come from? -They come from the Sun! – Well the sun sends energy in the form of light, but it doesn’t send the particles to build the plant, although it provides the energy needed to build the tree .Where does the atoms that make up the tree come from? - From the soil?- No. Important minerals are taken by the plant from the soil, but not the actual building blocks . Try again! - I don’t know.
It is seem difficult to identify that air provides the basic material to build the plant, although pupils knew the equation for photosynthesis (at least the word equation).
Some pupils (only 2) had a lower level response, where the conservation of mass and volume didn’t apply:
-Where does the materials to make up that huge tree (RO points at the a tree on the field) come from?
-The plant makes them. Cells divide and make new cells. That’s how a plant grows.- Yes, OK. The plant organizes the materials (atoms) around it and grows, by building large and complex molecules. But it still needs to get building blocks in order to do it. .-Where do they come from? – From the soil? – No, from the air!
Pupils that give this explanation may not recognise the conservation of matter, volume and substance . These notions of conservation are required in order to progress further and acquire an atomistic view of nature (Piaget,1962 ).
-Final commentsKids were very keen on answering the questions. I found the interviewing is the best way of collecting data, as I can do an assessment by looking at their reactions. I can also find out if they are unsure, or if they are being influenced by the other peers present.
Some times I found that there is a pupils present that has a very good understanding and knows all the correct answer. In that case I asked to the less able pupil to answer the question first.
This research was rewarding for me, especially when students become puzzled and want to know the answers . They also wanted to know why I was asking those questions-at break time and lunch time- and they were happy when I gave an explanation (for my research, for the university).
It is interesting to ask pupils unusual questions, about facts that they take for granted. Questions like why metals shine or why is the sky blue don’t seem to require an answer, and that why they are so intriguing. It also provides inspiration for pupils to question the world…
The particle model is extremely important , because it provides explanations for a wide range of phenomena: chemical reactions, osmosis (where the particles of solute can be seen as a gas), physical transformations. It is important to visualize that the particles move at high speeds, to understand that they collide heavily in order to undergo a chemical transformation.
Interviews with university students
Perhaps I was expecting too much from the pupils, because most people don’t know the answers to these questions anyway. I decided to interview some university students and I found that they had difficulty in answering questions about evaporation (water puddles, kettle) and burning (candle). Although some people gave good answers, no one managed to answer all the questions correctly. Furthermore, they didn’t look very sure about what they were saying, even when it was correct. I have used flash cards in these interviews .
The interviewee is shown a card picturing vapour bubbles forming inside a boiling kettle. The first question is what you see, followed by what is inside the bubbles. Most people said that there was air or oxygen inside the bubbles.
Two students gave very good answers to the questions related to the evaporation of water (on the kettle and on the street puddles), but were caught up by the questions on the candle. When I showed a picture of the candle alight and then the same candle after 3 hours, they said that it had melted. Then , I asked if they had the same weight. That question caused puzzlement, because they couldn’t deny the conservation of substance (they were formal operational thinkers), but at the same time they couldn’t see where the material had gone.
This questioning involving university students was interesting and showed that is common that people have misconceptions about the particle model. So, it shouldn’t be a surprise that school children also have difficulties in understanding it.
