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Name: Class: Date:
Test Your Understanding: Diffusion Cell Size Lab (student handout)
Procedure:
1. Record all three dimensions for each of the cell models in Data Table #1.
2. Calculate the total volume for each cell model based on the formula below and record it in Data Table #1: Volume (cm3) =
Length (cm) x Width (cm) x Height (cm)
3. Calculate the total surface area of each cell model using the formula below and record it in Data Table #1: Surface Area (cm2)
= Sum of areas of each side of the cell model (6 sides total)
Hint: To find the surface area of a single side of the cell model, multiply the length of the side (cm) by the width of the
side (cm).
4. Calculate the surface area-to-volume ratio for each cell model and record it in Data Table #1. Use the following formula:
Ratio = Surface Area
Volume
5. Gently place the three agar cubes into a clear cup. Pour the diffusion media into the cup until the agar cubes are completely
submerged. Record the starting times as soon as you place the cubes in the diffusion media. Allow diffusion to occur for
10 minutes. Observe any color changes which occur in the agar cubes.
6. After 10 minutes, pour out the diffusion media, remove the cell models, and place them on a clean paper towel.
7. Slice each block in half and measure the diffusion distance from the outer edge of the block to the point where the color
change stops. Measure the diffusion distance on the opposite side and add the two distances together to obtain the total
diffusion distance for each block. Record your measurements in Data Table #2.
Data Table #1
Cell Model # Length (cm) Width (cm) Height (cm)
Total Surface Area
of cell model (cm2)
Volume of cell
model (cm3)
Ratio of Surface Area:
Volume
1
2
3
Data Table #2
Subtract the Diffusion Distance from the Cell's Dimensions
(from Data Table #1)
Cell Model #
Total Diffusion
Distance (cm)
(Sum of opposite sides)
Length minus
diffusion distance
(cm)
Width minus
diffusion distance
(cm)
Height minus
diffusion distance
(cm)
Volume of cell
model not affected
by diffusion (cm3)
1
2
3
