Objectives:
1. Students will use carrots as cell models and demonstrate diffusion and osmosis,
by measuring and observing the changes in the mass and size of the carrot.
Materials:







Two cups
string
measuring tape or meter stick
salt
water
triple beam balance
carrots
Procedures:
1. Take your day 1 measurements. See data tables. Fill two cups with 100 ml of each solution.
Solution A salt water and Solution B tap water
2. Cut a carrot in half. Tightly tie a piece of string two cm below the cut end of both pieces.
3. Place one carrot half (cut end down) in one cup. Be sure to label with your group color and
period. Label the cup "Salt Water". Place the other carrot with cut end down in the "Fresh
Water" cup. Allow carrots to remain undisturbed for 24 hours.
4. Form your hypothesis. Be sure to use correct format
5. After 24 hours remove the carrots and observe them and the tightness of the strings. Record
data data.
6. At the conclusion of your experiment, answer the following questions (realize that some
require deeper thinking than others?
Hypothesis:________________________________________________________________
Data Table:
Quantitative Observation
Quantitative
Observation
Day 1 mass (grams)
Day 2 mass (grams)
Carrot in Salt Water
Carrot in Tap Water
Quantitative
Circumference of carrot
Circumference of carrot
Observation
Day 1 circumference
Day 2 circumference
Graph:
1. Create two graphs:
Graph A: Mass
Graph B: Circumference
Post Lab Questions (results): Complete sentences
1. Describe what happened to the thread in fresh water. Salt water.
2. In which type of water did the carrot cells increase in cell size (freshwater or salt water?
(What evidence supports your response?)
3. In which type of water did the carrot cells decrease in cell size (freshwater or salt water?
(What evidence supports your response?)
4. In potatoes/carrots, what cell part stores water?
5. How do you predict human blood cells would be impacted if they were placed in a beaker of
salt water?
Extended Writing:
Compare and contrast the processes of diffusion and osmosis. Why are both of these processes
important in cells maintaining homeostasis (stability)? If cells did not have these processes how
would this impact the body? (7 or more sentences)