Cell Size and Surface Area a.k.a. “Pink GelO”
Purpose: What is the relationship between diffusion rates, cell size and cell volume? When cells grow to a certain size, their rate of growth slows down until they stop growing entirely. They have reached their size limit. At this point, they might under go mitosis or not. When one of these larger cells divides into two smaller cells, the rate of growth again increases. In this investigation you will explore one of the factors that limits cell size and growth rate. Materials needed for cell activity and growth must in some way gain entrance into the cell. At the same time wastes must be eliminated from the cell.
Materials:
3 “ice cubes” of 2% gelo (agar) + 0.04% bromthymol blue
millimeter ruler
100 ml white vinegar
plastic spoon, plastic table knife, paper towel
small bowl
white piece of paper (to serve as a background to observe the reactions)
Procedure:
Cube shape 
Cube Dimension 
Surface Area 
Volume 
Simplest Ratio 















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*Calculations:
Surface area of a cube = length x width x number of surfaces
Volume of a cube = length x width x height
Ratio of surface area to volume = surface area
Volume
The ratio may also be written “surface area: volume” The ratio should be expressed in its simplest form. To do this, divide both terms by the second term. Example: The surface area of a cube is determined to be 24cm^{2 }. The volume is calculated to be 8cm^{3 } The ratio of surface area to volume is 24/8 or 3/1 or 3:1.
Smallest ______cm

Medium ______cm 
Largest ______cm 
Discussion/Conclusion