X cName ______Date ______

Osmosis Grape Lab

Materials:

3 grapes

3 small containers

Electronic balance

Salt water solution

Distilled water

Grape juice

Marking pen

Procedure:

Day 1

  1. Label 3 containers as follows: “Distilled water”, “Salt water”, and “Grape juice” along with your name.
  2. Label the 3 dry grapes with the same labels as above using the marker.
  3. Get the mass of each of the three grapes. Record the masses on your data table for the Day I mass. (note which balance you used on Day I) Balance # ______
  4. Put one grape into each of the three containers. Add 40 ml of each of the solution to the container
  5. Let the containers sit overnight or weekend in the location designated by your teacher

Day 2: Be certain to use the same balance as Day I and that the balance is dry.

  1. After the allotted time, take the grapes out of their containers and dry them off. Observe the condition of them. See if there are cracks, if it’s swollen or is it mushy.
  2. Thoroughly dry and then re-mass each grape using the same balance and record their Day 2 masses. If it lost mass, be certain to include a negative in front of the mass.
  3. Dump the liquids down the sink and then throw away the grapes and the containers.
  4. Calculate the percent mass differences and record these on your data table. Round to the nearest 0.1g

% Mass Difference is calculated as: Day 2 mass – Day 1 mass x 100

Day I mass

Data Table: Change in mass of grapes in solutions after a day.

Day 1 Mass (grams) / Day 2 Mass (grams) / Difference in mass (in grams) (Day 2 - Day 1) / % Difference in Mass (grams) / Net Movement of water (Into grape, out of grape or no net movement) / Type of Solution (Hypotonic, Isotonic, Hypertonic) / Observations
Distilled water
Grape Juice
Salt Water

Analysis: Answer all of these questions in full sentences for full credit.

1.  Explain why the grape in grape juice stayed around the same mass and had the least percent change in mass.

2.  What happens to lettuce when it has salt added to it and then it sits for awhile? Explain your answer using the information from your lab.

  1. If the vegetable you are going to use is wilted, what should be done to bring it back to normal? Explain your answer using the information from your lab.
  1. Why are you so thirsty after eating a meal of French fries, a hot dog and regular soda? Relate your answer using the information from your lab.