Cell Surface Size Activity

This is a multi-day lesson plan that could be used in whole or part.  Part one begins with constructing cubes and calculating volume, perimeter, and surface area.  Part two involves using phenolphthalein agar blocks and sodium hydroxide to mimic movement of materials into a cell, and part three involves creating a spreadsheet to calculate volume – surface area ratio. Students explore the connection between cell size and functionality to establish the need for cells to undergo division.  This knowledge connects to cell organelle functions and movement of materials across the cell membrane.

Standards & Objectives

Academic standards
CLE 3002.2.6
Deliver effective oral presentations.
CLE 3210.1.4
Describe the processes of cell growth and reproduction.
CLE 3210.1.5
Compare different models to explain the movement of materials into and out of cells.
Alignment of this item to academic standards is based on recommendations from content creators, resource curators, and visitors to this website. It is the responsibility of each educator to verify that the materials are appropriate for your content area, aligned to current academic standards, and will be beneficial to your specific students.
Essential and guiding questions: 
  • Which cell has the greatest volume?
  • Which cell has the smallest volume?
  • Which cell has the greatest surface area?
  • Which cell has the smallest surface area?
  • Which cell has the greatest surface area to volume ratio?
  • How many small cubes do you think it would take to fill the medium cube?
  • To maintain life, and carry out cellular functions, materials must be able to move into and out of the cell.  Also, material needs to be able to move within the cell. What might be the advantage of having a large surface area?
  • What might be the disadvantage of having a large volume?  
  • Explain how a small change in cell size can have a huge impact on the cell and its normal functions.
  • So why are cells so small?

Lesson Variations

Blooms taxonomy level: 

Helpful Hints


  • Scissors 
  • Paper cube patterns 
  • Tape or glue 
  • Metric ruler