Knowledge versus understanding in science

I am going share with you a question that has been bothering me for some time: what is the difference between knowledge and understanding?

Schemata – where you put your knowledge matters

In 1923 Jean Piaget introduced the term schema. A schema is an organised group of related ideas – see an example of a schema on the right for plants.

We can think of a schema as a mental structure where related information is categorised and grouped together. Students will have developed many schemata for different areas of science e.g. heavy things sink, light things float; each framework is unique to them.

Some of these schemata will be right and some will be wrong – scientifically speaking. For example, some schemata will be effective in students’ day-to-day lives e.g. “shut the door Graeme, you’re letting the cold in” but won’t fit the scientifically accepted ideas. When we acquire new knowledge it is generally fitted into these existing schemata – Piaget called this assimilation. Very occasionally, ideas will not fit an existing schema and the schema will need to be modified – Piaget call this accommodation. If students meet knowledge that they can’t relate to pre-existing ideas then this will be stored in isolation – a danger of rote learning.

Understanding requires meaning making

Understanding is all about meaning making. It involves placing new knowledge into the ‘right place’ so that we can construct sense from the various ideas that the new information is linked to.  A student who integrates new information correctly into existing, complimentary schemata, will understand. A student who integrates knowledge into contradictory frameworks, or who stores knowledge in isolation, will become confused. Both students acquire knowledge but only one student understands it.

Ducks are birds and birds are animals

We can see this type of confusion in many science lessons where new knowledge is integrated improperly into developing schemata to create misunderstandings e.g. thinking plants respire only at night and photosynthesise in the day, humans evolved from chimps, heavy things faller faster than light things or atoms are solid balls.

Let’s look at a specific example in more detail. Many students think that birds are not animals. If the student is told by a teacher that ducks are animals, then they may just conclude that ducks are not birds – after all, this requires the least amount of mental reorganisation. In this example knowledge was acquired i.e. ducks are animals, but without a proper understanding i.e. ducks can belong to both bird and animal groups. The barrier to understanding here lies in how this knowledge was integrated and organised.

Helping students to understand in science

So, how can we help students to make meaning? Here are a few simple ideas to try in the classroom:

1. Always take account of prior knowledge at the start of the lesson – we want to make sure existing schemata are activated and scientifically acceptable before new ideas are introduced
2. Where common misconceptions are likely to exist e.g. ice will melt faster on ‘warmer’ plastic than ‘colder’ metal, then employ cognitive conflict strategies and spend time unpicking why the misconception is wrong
3. Take account of progression when you plan lessons and SOWs. This will help students organise fruitful schemata e.g. students need to know about magnets, electromagnets and current before they begin learning about motors
4. Use concept maps to reveal the relationships between knowledge

Further reading

• Piaget, J., & Cook, M. T. (1952). The origins of intelligence in children. New York, NY: International University Press. (http://www.simplypsychology.org/piaget.html)
• Atlas of Science Literacy is a two-volume collection of conceptual strand maps—and commentary on those maps—that show how students’ understanding of the ideas and skills that lead to literacy in science, mathematics, and technology might develop from kindergarten through 12th grade