Lab Manual - eScience Labs

Lab 5: Chemistry of Life
Experiment 2: The Effect of Surface Area and Volume
Have you ever wondered why cells don’t grow past a certain size? There is a size limit for cells that
they cannot surpass. Once they reach their maximum size, they divide and form two smaller cells. Why
do they do that? We will look at the importance of surface area to volume raos in this experiment to
help you understand.
Materials
1 Nutrient Agar Bole (125 ml)
10mL Bromothymol Blue
Plasc wrap
Pipees
Vinegar
2mL Sodium bicarbonate
(1) 250 ml beaker
Rectangular mold
Ruler
Kitchen knife*
Microwave*
Hot pads*
*You must provide
Note: This experiment requires preparaon 24 hours in advance.
• To determine surface area, mulply Length x Width of each side of the cube and then add them
together. This should be 6 different values added up. For example, if a cube were 3cm x 3cm x
3cm each side would have a L x W = 9 cm 2 . There are six sides in a cube so you would add up the
L x W, in this case 9 cm 2, for all six sides. That would give you a surface area of 54cm 2. . If all the
sides are not the same length, you would determine the length x width for all six sides and add
them up as well.
• To determine volume, simply mulple Length x Width x Height.
9 cm 2
• To determine surface area to volume rao, simply divide the surface
area by the volume. 9 cm 2
Procedure
Preparaon
1. Begin by removing the cap off the agar soluon and placing it in the microwave for 30 seconds.
While in the microwave, watch the soluon for boil-over. If it begins to boil-over, im-
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