The big ideas of science

Author: Sue Howarth
Published: 25/08/2020

What are the big ideas of science?

These are 10 ideas that help students understand the interconnections of science, despite the often-perceived standalone nature of science lessons.

Imagine a student who:

  • burns crisps in a biology lesson, then
  • watches a Van De Graaff generator operating in physics, and then
  • learns about crude oil in chemistry.

Instead of three separate lessons, these are actually, in different ways, all teaching about different aspects of energy, one of the ‘big ideas’ of science.

How is a ‘big’ idea different from a ‘small’ idea?

  • Big ideas are overarching ideas that can be applied to a wide range of related events or phenomena.
  • Small ideas have more limited applications, and usually apply to specific objects or events. 

The idea of enzymes in saliva breaking down starch in food is a small idea. It becomes bigger as more enzymes, the digestive system and the nutrition of other animals are studied, until it develops into a generalisation that applies to all organisms. This example is part of the big idea: organisms require a supply of energy and materials for which they are often dependent on, or in competition with, other organisms.

Big ideas are built from small ideas that link together. Big ideas are not taught directly but help link all of the related small ideas together under one ‘umbrella’.

Why should you know about the big ideas?

Using the big ideas can help students see science as one, large picture, rather than many isolated ideas. Used appropriately, the big ideas should help students understand how science works and better understand the scientific aspects of the world around them. It could even be argued that once students appreciate the big ideas, they may find that science makes more sense and enjoy studying it more.

The big ideas can also help you, as a teacher, realise that what you have to teach is not a long list of fragmented topics, but actually many coherent pieces that fit together to make the wonderful jigsaw called science.

Where have the big ideas come from?

A group of international science educators concerned with improving science education worked together to create the report: Principles and Big Ideas of Science Education (Harlen, 2010). They felt that students’ science education across primary and secondary school mostly lacked coherence, perhaps because of historical reasons, but also due to syllabus development that over focused on content. Focusing on specific topics can obscure the important, overarching, key ideas in science, rather like ‘not seeing the wood for the trees’, so the big ideas were developed to allow students to appreciate ‘the wood’, or the big, important ideas of science.

How can you use the big ideas?

Use the big ideas as often as possible to help students put the ‘jigsaw’ together.

For example, you could:

  • put them in your lesson plans so that you always retain the bigger picture
  • mention them to students each time you start a new topic
  • ask students which big idea or ideas the lesson is about
  • keep the big idea or ideas in mind during lessons, so that it informs your questions and feedback to students
  • suggest that your science department maps out the big ideas for each year group to help you, other teachers and your students see the connections.

Do the big ideas work?

A follow-up report, by the same group of educators: Working with Big Ideas of Science Education (Harlen, 2015) suggests that:

  • responses from users in many countries confirm that the big ideas are relevant
  • the big ideas have been used in reforming some national curricula.

It has also been suggested that: 

  • a smaller number of more powerful ideas can explain experiences for students better, and are easier for students to remember than a larger number of smaller ideas
  • ideas that progress from ‘small’ to ‘big can help students to make sense of their expanding knowledge and understanding
  • working with the big ideas enables students to identify connections between all the sciences and helps them to apply ideas in new situations (Harlen, 2018).

More useful information about the big ideas

First, here are the 10 big ideas.

  1. All material in the Universe is made of very small particles.
  2. Objects can affect other objects at a distance.
  3. Changing the movement of an object requires a net force to be acting on it.
  4. The total amount of energy in the Universe is always the same but energy can be transformed when things change or are made to happen.
  5. The composition of the Earth and its atmosphere and the processes occurring within them shape the Earth’s surface and its climate.
  6. The solar system is a very small part of one of millions of galaxies in the Universe.
  7. Organisms are organised on a cellular basis.
  8. Organisms require a supply of energy and materials for which they are often dependent on or in competition with other organisms.
  9. Genetic information is passed down from one generation of organisms to another.
  10. The diversity of organisms, living and extinct, is the result of evolution.

An extra four ideas are big ideas about science.

  1. Science is about finding the cause or causes of phenomena in the natural world.
  2. Scientific explanations, theories and models are those that best fit the evidence available at a particular time.
  3. The knowledge produced by science is used in engineering and technologies to create products to serve human ends.
  4. Applications of science often have ethical, social, economic and political implications.

Associated with the big ideas of and about science are 10 principles of science education. One of these is the 'main purpose of science education should be to enable every individual to take an informed part in decisions, and to take appropriate actions, that affect their own wellbeing and the wellbeing of society and the environment.’ The other nine principles can be found in Principles and Big Ideas of Science Education (Harlen, 2010).

In Working with Big Ideas of Science Education (Harlen, 2015 pp 20–33), each big idea is usefully developed and explained, one page per idea. Progression within each idea is also mapped by age range (7–11, 11–14 and 14–17).  Reading these could help you to make sense of the many science topics that you are likely to be asked to teach during training and in your first year.


Harlen, W. (2010) (ed.) ‘Principles and Big Ideas of Science Education’. Association for Science Education.

Harlen, W. (2015) (ed.) ‘Working with Big Ideas of Science Education’. Association for Science Education.

Harlen, W. (2018) ‘Working Towards Big Ideas: Implications for the Curriculum, Pedagogy and Assessment’.

Next Generation Science Standards (2018).

Sue Howarth

Sue Howarth is an ASE Chartered Science teacher, a former teacher-trainer at the University of Worcester, and author of a number of publications, including 'Success with STEM'.