Misconceptions

I was delighted to be asked to record a short video on misconceptions for the #ChatPhysicsLive conference, but also a little bit apprehensive as the topic is a massive one! I knew I could only provide an overview of it, so here is a blog post to flesh out some of the ideas I mentioned, provide some more context and links to further reading.

First, I just want to highlight that the good practice described in the EEF’s Improving Secondary Science report underpins a lot of what I will be describing. In order to address common misconceptions we need to employ metacognition, we will often use modeling and practical work, we absolutely must develop students’ literacy, consider how memory works and also use diagnostic assessment and give students formative feedback.

In this blog post I will focus on what misconceptions are, the steps I take to address / prevent them, and share an example of how I put these ideas into practice.

Here’s the plan:

1. What are misconceptions?
2. How can I address / prevent misconceptions?
3. An example: addressing a common misconception about forces
4. Further reading

1. What are misconceptions?

It’s clear that some areas of physics cause real difficulties in understanding for many students. I’m going to use the term ‘misconceptions’ because it’s the word that teachers are familiar with, but if you read physics education research, you will see lots of different terms used, for example:

• Preconceptions — all the ideas that students come to your lesson with.
• Alternative conceptions — many researchers prefer this term over ‘misconception’ to recognise that they are not mistakes, but rather they are non-scientific ways of making sense of the world, which make sense to students.
• Conceptual difficulties: to highlight that it’s not just about having the ‘wrong’ knowledge but about ways of thinking and applying that knowledge.

How is a misconception different from a mistake? I think Andrea diSessa helps make an important distinction (using the term conceptual change):

“Some topics seem systematically extremely difficult for students, and conventional methods of teaching usually fail… Conceptual change contrasts with less problematic learning, such as skill acquisition (learning a physical skill or an algorithm for long division) and acquisition of facts (such as “basic number facts” for addition or multiplication). If there are difficulties in these areas, they are for more apparent reasons such as sheer mass of learning or the necessity of practice to produce quick, error free performance”

- Andrea A. diSessa, 2014

The way I understand it, a misconception involves reasoning that makes sense to the student and that gets them to an incorrect answer — even though it may be based on some correct information. Whereas a mistake tends to be about not knowing, misremembering or misunderstanding factual knowledge.

Here are some examples:

• F = m/A is a mistake — they’ve misremembered knowledge or misapplied a procedure
• ‘All metals are magnetic’ is a misconception — students have taken their knowledge or observations (e.g. that only metals are magnetic — which is correct) and misapplied or in this case over-generalised them, thus thinking that all metals are magnetic. This may be reinforced by their knowledge that all metals conduct electricity, and so they might think that magnetism must also be something that all metals have in common. This involves reasoning and so is a misconception rather than a mistake.

Why should we explicitly address misconceptions?

“teachers who know their students’ most common misconceptions are more likely to increase their students’ science knowledge than teachers who do not know. Having a teacher who knows only the scientific ‘truth’ appears to be insufficient. It is better if a teacher also has a model of how students tend to learn a particular concept…”

- Philip M. Sadler and Gerhard Sonnert, 2016

Much of physics is abstract, and it often relies on evidence that cannot be directly observed by our senses. Because of this, learning physics requires students to form mental models of concepts, which may be several steps removed from their experience. As teachers we need to guide students carefully through these thinking leaps and jumps.

If we don’t explicitly address misconceptions, they tend to stick around… If we just teach students what they need to know and don’t teach them the reasoning process of how to get there, they will tend to continue to pursue their original line of reasoning (which makes sense to them) and still arrive at the original misconception, even after you’ve taught them the ‘right answer’.

2. How can I address / prevent misconceptions?

“Students do not just lack knowledge; they think differently than experts”

- Andrea A. diSessa, 2014

It’s not just knowledge that we need to teach our students, but we also need to teach them to think like a physicist. This means, for instance, that we need to teach them ways to think about and analyse problems, how to recognise the physical principles that are relevant to the problem in front of them, and how to make links between areas of knowledge. We need to teach them what to notice and what they can ignore — the assumptions we make in different situations.

The below XKCD cartoon may be silly, but I do think it is a helpful reminder that a physicist will tend to approach the world in a slightly different way from, say, a botanist or an artist.

As a teacher I strive to make my ‘internal physicist monologues’ explicit to my students. This requires a great deal of talking about what I’m thinking about as I analyse phenomena and approach problems — what we might call metacognition. As teachers of physics, we need to consider what is particular about the way that we think as physicists— and how we best teach our students to think in that way. I will share some examples of what this might look like in part 3 of this blog post.

My approach to addressing misconceptions involves four steps:

0. Find out about common misconceptions for this topic! (I call this step 0 because it takes place before the lesson!)

1. Assess students’ knowledge and scientific reasoning

• I think it’s particularly important to understand their reasoning — diagnostic questions are incredibly useful for this

2. Develop students’ knowledge and scientific reasoning

• Provide dissatisfaction with their existing ideas and reasoning, and provide evidence for the new, more scientifically accurate way of thinking
• Make links between existing knowledge and new / scientific concepts, for instance through concept mapping
• Model scientific reasoning and expect it of students — ask them to share their thinking e.g. “What were your steps to working that out?” “Which principle could you use to solve this problem?” “What assumptions can you make?” “How can we break this situation down?” “What is changing and what is staying the same? How do you know?”
• Guide students to explicitly recognise changes in thinking and reasoning
• Introduce the ‘correct’ idea early on — the earlier we introduce correct ideas and scientific ways of thinking, the better!

3. Explicitly address & assess misconceptions in a variety of contexts

• If you just consider one context, students are likely to forget their new reasoning, and they may have difficulty applying their new way of reasoning to other situations

Useful tools & strategies for addressing misconceptions

These are some of the tools that I find myself using a lot for addressing misconceptions, and embedding new ideas and ways of thinking. I will focus on a few of them in this particular blog post, but I’m sharing them in case you want more ideas to look into later!

• Teaching models (see this blog post on using models to teach circuits for an example)
• Concept mapping
• Frayer models
• Concept cartoons
• Refutation texts
• Bridging analogies
• Powerful demos
• Storyboarding (see this video on charge and static that I made for the IOP)
• Systems thinking
• Thought experiments

3. An example: addressing a common misconception about forces

0. Find out about common misconceptions for this topic

These are the resources I tend to use to find out about the misconceptions my students are likely to hold (and to find diagnostic questions):

• Misconceptions in Primary Science by Michael Allen
• Making sense of secondary science by Rosalind Driver et al.
• Uncovering student ideas in science by Page Keeley
• Five Easy Lessons by Randall D. Knight
• IOP Spark website
• Best Evidence Science Teaching resources
• AAAS Project 2061 website

For example, here is a common misconception about forces from the misconceptions section of the IOP Spark site:

‘If an object is moving then there must be a force acting on it’ — this is based on students noticing that objects on Earth slow down and eventually stop moving if there isn’t a force acting on them. In everyday situations, if you want something to keep moving you have to keep exerting a force on it, as objects on Earth are continuously affected by resistive forces —most commonly air resistance and friction, which cause them to slow down.

Knowing that this is a common misconception, I would take some time to identify relevant diagnostic questions or tasks that can help me gain an insight into my students’ reasoning on this subject. For KS3 (age 11–14 in England) I would tend to turn to the BEST resources or IOP Spark, or for KS4–5 (age 14–19) my go-tos are IOP Spark and Five Easy Lessons. Often these will be multiple choice questions, and sometimes they will be ‘two-tier’, i.e. they have a second level of questioning asking students about the best explanation for the answer they have given.

Before the lesson I also have a think about ‘stepping stone’ or scaffolding questions, which can prime students to notice or think about things that are helpful. In this case, ‘why does a ball stop rolling around the ground?’ is helpful as it gets them noticing the resistive forces. That can then lead to the question ‘what would happen if there were no friction or air resistance?’

One strategy for finding out how students reason about forces is the idea of ‘force spectacles’, which I came across on the IOP website. This is an example of a thought experiment. I share with students that physicists often use thought experiments — they’re great for helping us think through something that we can’t do in real life, Einstein for instance was very fond of them. Thought experiments require us to use our imagination to think about something we can’t see.

In this case, forces are abstract — they’re not something you can see, you can only see their effects. So I give students a series of scenarios and say “there are forces acting in each of these situations, you know this from primary school. I’m going to ask you to put on a pair of force spectacles, they will turn the forces that you can’t see into forces that you can see, through the power of your imagination! So when you put them on you will see the forces and I want you to draw them on this piece of paper. When you do this, I want to you think about which object the force is exerted by, what kind of force it is (if you can name it) and which object the force is acting on.”

Note that I’m using the precise scientific language that I expect students to use — exerted by, acting on — and being specific about what I want students to do. This is me modeling the thinking of a physicist — these are the questions a physicist might ask themselves when observing and thinking about forces. Being precise about the language is important to help students develop their understanding of the concepts they relate to.

Students will usually draw a picture a bit like this:

They will almost always draw ‘thrust’ or a ‘push’ force pushing the place forward, even though I was clear that the plane is flying through the air.

2. Develop students’ knowledge and scientific reasoning

My next step is to show them how to think through this situation like a physicist. I’ve written before about the concrete pictorial abstract approach, and how important it is to start with concrete, ideally familiar situations before moving onto abstract ideas in physics. And so I will always look for a practical experience (or if that’s not possible a teaching model or thought experiment) as the starting point for developing students’ understanding. I would usually do this in the classroom with a student throwing the paper plane, but since teaching remotely I have started to use a toy monkey (called Monkey) for demonstrations under the visualiser, which I find works very well.

I try to be as explicit as possible about why I’m approaching the situation in the way that I am: “one of the things we do as physicists is to break down observations or problems into stages. This makes it easier to analyse them. We’re particularly interested in comparing different parts of a problem where something might have changed. So, when throwing a plane you’re got the moment when the plane is being held still. Then you’ve got the moment when it’s started moving but just before it’s let go. And then the moment after it’s let go. Something has changed between all of those three moments, so they’re good moments to analyse and think about what’s changing and what’s causing the changes.” Note that when talking about forces I guide students to focus on the changes in motion.

I then ask students to remind me which questions physicists might ask when analysing problems involving forces:

1. Which object is the force exerted by?
2. What kind of force is acting?
3. Which object is the force acting on?

Depending on the age of the students, I might introduce the term ‘interaction’, explaining that because forces are interactions between objects, we always need to consider both objects involved in the interaction. This provides a reason for these being important questions.

I then interactively model (by which I mean I ask lots of questions while modeling) drawing force diagrams for each of these three situations, as you can see in the picture below.

I would usually start by trying to draw the object but then say “if I have to draw this object every time it’s going to take me ages, is there a simpler way I could represent it?” and so I introduce the idea of a free-body diagram. Next time I do this I might ask “am I going to draw the object? No, that’s right, it would take ages, what shall I draw instead?” Whilst drawing the diagrams I ask students for guidance, crucially for the third diagram of the plan after letting go: “is there a force from Monkey’s hand holding it up?” They are usually confident that the answer is no. “Is there a force from Monkey’s hand pushing it forward?” There is often a pause. You can almost hear their brains whirring… “No… Monkey isn’t pushing it… But there should be… Because it’s moving… But…”

This is the penny drop moment for most students. Most students really feel that there should be a force pushing the plane forward. It seems so intuitive! I take a moment to be a bit dramatic, “Does it have a motor inside it?” I open it up. “Is there a little physics fairy pushing it forward? No. There is nothing pushing this plane forward. It is continuing to move because when an object is moving it will continue to move in the same way until another force acts on it.” Depending on the age of the students I may introduce the idea of inertia, which gives a name to the tendency of objects to continue moving at a constant speed (or to continue not moving!). I will also use this example to pin down what resultant forces can do: forces can change the shape, direction of motion or speed of motion of an object.

Once you’ve gone through this chain of reasoning with students you want them to recognise how their ideas have changed. I picked up the idea of post it note reflections from Shirley Clarke, who’s done some fantastic work on formative assessment in primary in particular, but there are plenty of other examples of refutation texts. The idea is to help students notice how their ideas have changed, or to show that a common misconception is wrong. Here is an example:

3. Explicitly address & assess misconceptions in a variety of contexts

You will generally find that, if you only do this once, misconceptions will tend to reappear. This is because students will easily forget their fragile new reasoning and fall back on their lifelong intuitive reasoning. It’s therefore crucial that we practice new ways of reasoning in a variety of contexts. I will return to other examples that I gave them, for instance the football after it has been kicked, show them their initial drawings and ask whether they have changed their mind about any of the forces acting in this situation. They will then see that it’s the same underlying idea — a force was exerted (from the foot) and acted on an object (the football), but the force is no longer being applied and the ball is still moving (inertia). It can also be helpful to use concept cartoons (such as the below example that I found on the STEM Learning website) and diagnostic questions. Finally, I like to give students a tennis ball, put a post it note on the floor and ask students to run past it and drop the ball so that it hits the post it note. To start with, students will often drop the ball right above the post it note and it will fall in front — or they will exclaim “Miss! It’s going to keep moving after I let it go! So I need to let it go a little bit before…”

Another nice follow-up is to consider what would happen if there were no air resistance, or no friction, or no gravity. Show them examples such as the feather / bowling ball drop, air tracks, hover crafts, ice skaters, or George Clooney in the film Gravity…

One more resource I highly recommend is Minds On Physics, which helps teach students to reason and solve problems in physics. I think it’s absolutely brilliant — it asks students to reflect on how to approach different problems, whether they solved different problems with the same approach, and as a teacher I learnt so much from it.

I mentioned at the start that students think differently from expert physicists. A big part of that is about how their knowledge is organised — students’ knowledge tends to be bitty and disconnected facts, whereas expert physicists have sophisticated schema organised according to physical principles. By making our thinking and reasoning explicit to students in the ways I have described in this post, we are helping them on their journey towards becoming expert physicists.

4. Further reading

Finally, here is some recommended reading if you’d like to find out more about this topic!

Driver, R. et al. (2014). Making Sense of Secondary Science: Research into children’s ideas.

IOP Spark article ‘Challenging common misconceptions when teaching physics’

McDermott, L. C. (2001). Oersted Medal Lecture 2001: ‘‘Physics Education Research — The Key to Student Learning’’

Taylor, A. (2017). ‘How to Help Students Overcome Misconceptions’

Tracy, T. (2018). ‘Guidelines for future physics curricula’. School Science Review.

Sadler, P. M. & Sonnert, G. (2016). ‘Understanding misconceptions’. American Educator.

Heavier reads:

diSessa, A. A. (2014). ‘A History of Conceptual Change Research: Threads and Fault Lines’

Gurel, D. K., Eryilmaz, A. & McDermott, L. C. (2015). ‘A Review and Comparison of Diagnostic Instruments to Identify Students’ Misconceptions in Science’

I’d like to thank my physics educator friends James de Winter and Dr Mark Hardman — my understanding of and thinking about this subject has developed a great deal thanks to conversations with them, as well as their reading recommendations :)