Prior knowledge in science lessons

I think we can all empathise with the feeling of frustration, when someone insists on showing us how to do something that we can already do. Similarly, it can be equally frustrating to be asked to do something that you can’t do.

Learning science is just the same. Students arrive into our lessons with a enormous amount of prior knowledge that we need to take account of. Some of this prior knowledge is right and some of this is wrong. And for may concepts in science, novices have had time to develop some pretty deeply held misconceptions e.g. plants get their food from the soil, a force is needed to keep something moving  or we evolved from chimps.

What is particularly important about prior knowledge, is it provides the framework for learning new knowledge. Any new knowledge students learn has to be assimilated in relation to these pre-existing ideas, which then lead to the construction of more elaborate schemata. This is the cognitive rationale (as opposed to the motivational rationale) for making science lessons relevant to students (Carey, 1986).  If we don’t check prior knowledge at the start of a lesson or topic:

  • we risk boring those students who already have some understanding
  • we can’t support students to make links between what they know already and the new knowledge – this supports meaning making and learning
  • we remove the opportunity to practice retrieval – an important part of memory making
  • we also remove the opportunity for identifying and addressing student misconceptions.

The task of trying to find out what 30 students think is not an easy one! It’s actually impossible. But, we can certainly gain an important impression of the collective prior knowledge of the class, which we can then use to teach responsively, both in the current lesson and upcoming lessons. For example, if we’re teaching evolution in Yr9, I might want to know what students can remember about competition, variation, reproduction and Darwin? I will also want to know what other experiences students are bringing to the classroom e.g. some may have watched Jurassic Park, or visited the Galapagos Islands. I will then use all this information to adapt the current lesson (e.g. students don’t know the term variation so I will teach this using the white board) over future lessons (students are saying that we evolved from apes –  I’m going to plan an activity around common ancestors next lesson).

Below are some strategies that I have found useful to explore prior knowledge at the start of a lesson or topic.

What do I, my partner and class already know?

Using spider diagrams to assess prior knowledge in science. Students complete a spider diagram on a topic chosen by the teacher. This example is for exothermic reactions. Students brainstorm on their own what they already know about exothermic reactions. They share their ideas with their partner and add to their spider diagram. Finally, the class discuss their ideas as a group and the teacher/student adds this to a class spider diagram on the board. The teacher can walk around during the activity to identify misconceptions and ascertain understanding. This can inform the next phase of the lesson. (PDF)

Ask students to draw concept maps

A concept map can be a useful tool to assess prior knowledge. It’s similar to the spider diagram above but a little more complex as it asks students to think more about the relationship of knowledge and how it fits together in a hierarchical structure. Concept mapping was originally developed by Novak and his research group as a means of representing frameworks for the interrelationships between concepts (Novak & Gowin, 1984). If you are going to use concept maps make sure you have trained students first about how to draw them. Click here for an excellent summary of concept maps.

Assessing prior knowledge by getting students to ask the questions

Imagine you are teaching the first lesson on satellites. You don’t want to start your lesson assuming students know nothing about satellites, but are unsure of what they already know. A powerful approach is to show an inspiring image and ask: what questions do you have? The subsequent questions asked by the class will reveal a great deal about prior knowledge and identify class experts. For example,  a student who asks, “What shape is the orbit?” is clearly familiar with the term orbit and understands that orbits have different shapes.

You will be amazed by the creativity of the questions in your class. Examples from this image included: How old is it? How did it get there? Did the Russians put it there? What speed is it travelling at? Are those solar panels? It’s a quick and powerful approach, so give it a try with an inspiring image.

Using diagnostic MCQ questioning

The AAAAS Project 2061 Science Assessment Website provides free access to some fantastic diagnostic MCQ questions to really assess students’ understanding and identify misconceptions. The multiple choice science test items assess students’ conceptual understanding, not just facts and definitions and test for common misconceptions and alternative ideas students have along with their correct ideas. Other sources for MCQs are listed here.

You can also make your own. These questions on evolution provided the stimulus for some really fruitful conversations about evolution and natural selection that helped to make prior knowledge visible.

Ask students to draw a picture

OK, so you may think this sounds a bit ‘low level’. But if the question is right then a picture can paint a 1000 words. Again, the conditions for the task need to be made really clear so that all students complete it, whether they enjoy drawing or not and in a clear time frame! It is really important that you ask students to annotate the features of the drawing so you can understand their thinking. In this example, are students drawing an ancestor that has features shared by both the cow and the pig, or are they drawing a half-cow half-pig misconception!?

Further reading
  • Carey, S., 1986. Cognitive science and science education. American Psychologist, 41(10), p.1123.
  • Driver, R. (2008) The Pupil as Scientist? Open University Press: Maidenhead UK.
  • Driver, R., Squires, A.,Rushworth, P. and Wood-Robinson, V. (1994) Making sense of Secondary Science: Research Into Children’s Ideas, London: Routledge.
  • Novak, J.D. (1991) ‘Clarify with Concept Maps- A tool for students and teachers alike.’, Science Teacher, 58 45-49
  • Novak, J.D. and Gowin, D.B. (1984) Learning How to Learn, Cambridge: Cambridge University Press.
  1. Clearly defined lesson objectives
  2. The Do Now
  3. Check prior knowledge
  4. Challenge your students
  5. Use context
  6. Use questioning to probe understanding
  7. Challenge all students appropriately 
  8. Use direct instruction to provide clear explanations
  9. Model abstract ideas in concrete ways
  10. Check for understanding – give and get feedback
  11. Troubleshooting  – why did it not work?!