Name:________________
Osmosis in Potato Slices Lab
Background:
Osmosis is the movement of water across a membrane. The direction that water moves, into or out of a
cell, depends on the amount of dissolved material surrounding the cell.
Question:
What happens to cells in a potato when they are placed in solutions containing different amounts of
salt?
Hypothesis:
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Procedure:
1. Label 3 clean beakers (100 – 250 mL) with your group’s name, class hour, and the words hypotonic,
isotonic, and hypertonic.
2. The prefix “hypo-“ means “below,” so the hypotonic beaker will contain water with less dissolved salts.
Pour 100 mL of distilled water into this beaker. Do not add any salt to this beaker.
3. The prefix “iso-“ means “same,” so the isotonic beaker will have roughly the same dissolved salts as the
inside of potato cells. Measure 0.5 grams of salt and add it to 100 mL of water, stirring to dissolve.
4. The prefix “hyper” means “above,” so the hypertonic beaker will have more salt than the inside of
potato cells. Pour in about 3 spoonfuls of salt and 100 mL water. Stir to dissolve as much salt as
possible, but expect that some of the salt will not dissolve and will sink to the bottom.
5. Select three slices of potato. Record observations about the texture of each before you place them into
the beakers. You will want three slices that are similar in size and texture, so that you can compare any
changes. Place one slice in each beaker and allow the beakers to sit overnight.
6. Remove potato slices, but keep track of which beaker they were in. Record any observations about
changes in their texture.
Data:
Type of
Solution
Amount of Salt
(per 100 mL
water)
Hypotonic
None
Isotonic
0.5 g
Hypertonic
Lots
Texture of Potato Slice
BEFORE
Texture of Potato Slice
AFTER
Results:
The potato slice in the __________ solution became more ___________,
while the potato slice in the ___________ solution became more
_____________.
Conclusion:
Write a paragraph to explain why the potato slices changed in texture. Think about what happened to the cells.
You will want to use the following words in your explanation: water, cell membrane, flow, hypotonic,
hypertonic, isotonic, solution. Use your best spelling, grammar, and sentence structure.
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