When Might You Start Teaching the Idea of Surface Area?

Last week Adam Boxer tweeted this:

Surface area is a powerful concept – students need to have a very well developed understanding of it before they can hope to understand rates of reaction, specialist cells, pressure etc. How might you develop a strong surface area schema?

Where to start?

I began my career as a high school science teacher (physics) – but 7 years ago I moved to primary. I know surface area is a concept learners struggle with even as late as A-level. So how far back would I go to start developing the idea of surface area?


  • Spread jam on a piece of toast? Two pieces? Three pieces? How much jam do you need?
  • Paint a small box, a medium box, a large box. How much pain do you need?
  • Why does my felt-tip keep running out when I could big areas?
  • How many biscuits can I bake on a tray?


At KS2, pupils calculate the area of squares, rectangles etc. first using squared paper and later by multiplying dimensions. They will be able to calculate the areas of compound shapes and use nets for 3D shapes.

They can answer questions such as:

  • How much carpet/grass seed/wallpaper would you need to cover xxx?
  • If 1 litre of paint covers 10m2, how much paint would you need to cover a wall with an area of 15m2?


Surface area is needed to understand: pressure; evaporation; specialist cells; villi and alveoli; rates of reaction; capacitance (film capacitors) and probably many more.

Linked Idea – Spreading Out

The ‘big idea’ of surface area links with ‘spreading out’ – sharing material/energy over a surface area:

  • Pressure (force)
  • Seasons (sunlight spreading over a larger area in the winter (northern hemisphere).
  • Absorption.
  • Flux linkage
  • Stefan’s Law

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s