Surface area — Science definition
Defined in 3 courses:
- How much surface is exposed; it governs the rate of any surface process, which is why food is chewed and the gut lining is folded. (Life Science & Scientific Inquiry)
- The area of a boundary available for exchange. (Life Science: Biology)
- The total exposed area of a solid; breaking a solid into smaller pieces increases it and speeds up reactions. (Physical Science: Chemistry)
Where it is taught
- Digestion, Absorption & Food Molecules — Body Organization, Transport & Movement, Life Science & Scientific Inquiry, Grade 7
- Cell Size & Exchange — Cells, Membranes & Exchange, Life Science: Biology, Grade 10
- Reaction Rates & Kinetics — Rates & Equilibrium, Physical Science: Chemistry, Grade 11
In use
The result is an enormous surface area packed into a few metres — estimates run to about thirty square metres, roughly the floor of a small room.
Digestion, Absorption & Food Molecules
Surface area describes the available boundary; volume describes the amount of interior to support.
Cell Size & Exchange
Questions using surface area
Problem 1
Why does increasing the surface area of a solid reactant speed up a reaction?
- it acts as a catalyst
- it raises the temperature of the solid
- it exposes more particles, so more collisions can occur at once
- it lowers the activation energy
Answer and explanation
it exposes more particles, so more collisions can occur at once
More exposed surface means more reactant particles are in contact, so more effective collisions can happen per second.
Taught alongside
- digestion
- enzyme
- absorption
- small intestine
- volume
- diffusion distance
- reaction rate
- collision theory
- effective collision
- catalyst
- inhibitor