Investigation:  The Effect of Salt on a Potato

What do you think will happen if you soak a potato in salt water overnight?

Pre-Lab Discussion:

1.  Consider what you know about osmosis and transport across the membrane and PREDICT what will happen to potato slices soaked in salt water.   Describe your predictions below.

2. If you are going to place potato slices in salt water, what do you need to set up as your CONTROL?  

Procedure and Data Collection: 

Use a scale to weigh your potato slices in grams. 

Mass of Potato Slice 1 ______         Mass of Potato Slice 2 ______ 

Place potato slice 1 in a cup of salt water, place potato slice 2 in a cup of distilled water. 

Use a sharpie to label the cups as SALT or DI water and write your initials.  Let sit overnight.

Weigh each of the slices the next day. 

          Mass of Potato Slice 1 ______         Mass of Potato Slice 2 ______ 

Analysis

3.  Describe what happened to the mass of each slice (did it go up, down, or stay the same).  Write in complete sentences.

4.  Refer to your notes or your understanding about osmosis.   Explain WHY you got these results.  Write in complete and thoughtful sentences, use the back of this page and use the following words in your explanation:  osmosis, cells, solution

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Other Resources on Osmosis and Diffusion

Observing Osmosis – use an egg, vinegar, corn syrup, will take a few days

Salt and Elodea – quick lab to observe the effects of salt water on elodea cells

Diffusion and Osmosis Crossword Puzzle – vocabulary review

Cell Transport Review Guide – with questions, definitions and images