Prior knowledge in science lessons

When we plan our science lessons, it is important we start by asking the question: What do our students already know? Any new knowledge has to be assimilated in relation to pre-existing ideas. This is the cognitive rationale (as opposed to the motivational rationale) for making science lessons relevant to students’ concerns (Carey, 1986) . If we assume students know nothing, we risk boring those students who already have some understanding. We also remove the opportunity of addressing and identifying student misconceptions.

Below are two strategies I find can help to identify what students already know at the start of a lesson or topic.

What do I, my partner and class already know?

Assessing prior knowledge in scienceUsing 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)

Assessing prior knowledge by getting students to ask the questions

What do Charles Darwin, Albert Einstein, Lynn Margulis and young children have in common? They all ask (or asked) excellent questions.

Science teachers need to encourage and capitalise on students’ desire to question. Why? Well, there are two main reasons. If we want our students to become outstanding scientists, we need to support them to ask (and answer) incredible questions. Secondly, the questions students ask reveal a lot about what they already know and therefore provide an important glimpse into students’ prior knowledge and current thinking.

Assessing what my students already know

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,
  • test for common misconceptions and alternative ideas students have along with their correct ideas
Further reading
  • 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.
  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?!