
Osmosis in the cosmosis
In this science experiment we will introduce you to a principle called osmosis. Using simple household items, we will demonstrate what osmosis is and how it works.
- Fill both of the dishes with water.
- Slice the potato lengthwise into several pieces that each have two flat sides.
- Add about two tablespoons of salt to one of the dishes.
- Put half of the pieces in the dish that contains plain water.
- Put the other half of the pieces in the dish that contains the salt water.
- Let the potatoes soak for 20 minutes.
Compare the potatoes. Notice any difference between the two?
Through osmosis, water naturally moves from areas of low salt concentrations to areas of high salt concentrations. Adding salt to the water creates a higher salt concentration in the water that is in the dish than in the water that is contained in the potato. Consequently, the water in a potato that is soaking in salt water will migrate out of the potato leaving a rather disgusting, mushy spud.
Advanced notes
This is a good time to explain the term ‘samples’ as used in scientific experimentation. In this experiment we have created two controlled environments – one dish with potatoes and salt water and another dish with potatoes in regular water. Both of these controlled environments are termed ‘samples’.
Potato osmosis experiment supplies
Supplies: Potato, Salt
Image Credits
In-Article Image Credits
Potato via Wikimedia Commons by Walter Peraza Padilla with usage type - Creative Commons LicenseFeatured Image Credit
Potato via Wikimedia Commons by Walter Peraza Padilla with usage type - Creative Commons License