Page 2
+
ward
'
s
science
5100 West Henrietta Road • PO Box 92912 • Rochester, New York 14692-9012 • p: 800 962-2660 • wardsci.com
Find materials for this activity at wardsci.com.
Discover more free activities at wardsworld.wardsci.com
Background Information, Activity Setup:
• Provide each lab group or station with a plastic knife, a cup/beaker, a timer, and a ruler.
• Distribute 3 different-sized cubes to each group (1 cm, 2 cm, and 3 cm) and the lab sheet/instructions.
• Walk through the directions of the lab with the class and then have them immediately get the experiment going.
• Ensure each group entirely covers their blocks with the vinegar so they are fully submerged in the liquid.
• During the 10 minute wait time, have the students complete the observation and hypothesis parts of the lab. Also, walk
students through how to complete the surface area and volume calculations in the first data table and how to calculate the
total diffusion distance once they cut the blocks in half to view them.
• Lab clean-up procedures: Put agar cubes in the trash and vinegar down the drain. Other supplies can be left on the lab table for
the next class.
Expected Results:
Students should find that the 1 x 1 x 1 cube diffuses almost fully within the 10 minutes, so it should turn completely white. Its
small size contributes to its ability to quickly diffuse throughout the entire block.
The 3 x 3 x 3 cube will still have quite a bit of pink remaining in the middle area, meaning diffusion did not occur in that area. This
represents parts of a cell that would not receive nutrients or gases. So, the larger a cell gets, the harder it becomes to get essential
materials to all of its organelles in a timely manner.
Diffusion Cell Size Lab (continued)
