Name: Date: Graded Assignment
Lab Report: Determining the Rate of Diffusion
Answer the questions below. When you are finished, submit this assignment to your teacher by the due date for full credit.
Total score: of 25 points
Completing Data Tables
(Score for Question 1: ___ of 5 points)
1. Look at the sample cube and example data table. Then complete data tables 1-4 based on your observations.

Example Data Table: Calculations for Sample Cube
Surface Area (SA)
Sides Length Width SA for Sample Cube
6 4 4

Volume (V)
Length Width Height V for Sample Cube
4 4 4

Surface Area-to-Volume Ratio
SA V for Sample Cube

96 64


Type your answer here.

Data Table 1: Calculations for Cube 1
Sides Length (cm) Width (cm) SA for Cube 1 (cm2)

Volume (V)
Length (cm) Width (cm) Height (cm) V for Cube 1 (cm3)

Surface Area-to-Volume Ratio
SA (cm2) V (cm3) for Cube 1 (cm-1)

Data Table 2: Calculations for Cube 2
Sides Length (cm) Width (cm) SA for Cube 2 (cm2)

Volume (V)
Length (cm) Width (cm) Height (cm) V for Cube 2 (cm3)

Surface Area-to-Volume Ratio
SA (cm2) V (cm3) for Cube 2 (cm-1)

Data Table 3: Calculations for Cube 3
Sides Length (cm) Width (cm) SA for Cube 3 (cm2)

Volume (V)
Length (cm) Width (cm) Height(cm) V for Cube 3 (cm3)

Surface Area-to-Volume Ratio
SA (cm2) V (cm3) for Cube 3 (cm-1)

Data Table 4: Diffusion Rates
5 Minutes in Vinegar:
Length of Side Distance Vinegar Diffused Diffusion Rate (mm/minute)
10 mm (1 cm)
20 mm (2 cm)
30mm (3 cm)
Analysis Questions
(Score for Question 2: ___ of 2 points)
2. Record your observations of how the agar cubes look before you add vinegar and after they are exposed to vinegar. How did the appearance of the cubes change?

Type your answer here.
(Score for Question 3: ___ of 2 points)
3. How do you know that vinegar diffused into the cubes? Does the diffusion distance differ between the cubes?

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(Score for Question 4: ___ of 2 points)
4. Look at your data tables. List the cubes in order from largest to smallest. Then list them again in order of the surface area-to-volume ratios, from the largest ratio to the smallest ratio. Compare the lists.

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Making Graphs
(Score for Question 5: ___ of 3 points)
5. Make a graph of your data, showing the distance vinegar diffused versus the surface area-to-volume ratio. Your graph should plot distance on the vertical axis, and the ratio on the horizontal axis. Plot the points on your graph and connect them with a line.

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(Score for Question6: ___ of 3 points)
6. Make another graph, this time showing the diffusion rate (mm/minute) versus surface area-to-volume ratio. Plot the rate on the vertical axis, and the ratio on the horizontal axis.

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(Score for Question 7: ___ of 2 points)
7. Observe the two graphs you made and analyze the results. What do the data tell you about the connection between the surface area-to-volume ratio and the diffusion rate?

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(Score for Question 8: ___ of 3 points)
8. If the cubes were left in vinegar for the longer period of time, which cube would you expect the vinegar to reach the center of first? Explain using the relationship between the surface area-to-volume ratio and the diffusion rate.

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Concluding Statement
(Score for Question 9: ___ of 3 points)
9. Using what you have learned in this exercise, write a paragraph applying the concepts. Describe a cell which effectively uses diffusion as a means to move materials in and out. Use this information to suggest how being small helps cells survive and being made of many small cells helps large organisms maintain homeostasis.

Type your answer here.