L3. OSMOSIS

OBJECTIVES:
1. Know about the osmosis phenomena
2. Understand the process of osmosis in plasmatic membranes

MATERIAL:

• Egg

• Potato 

• NaCl

• Distilled water

• Acetic Acid (Vinegar)

• Spatula 

• 600mL Beaker

• 3 Watch glass

• Knife

PROCEDURES:

Egg:

1. Take a 600mL beaker and put inside the egg.

2. Cover the egg with vinegar and make note of what’s happening. 
Once the egg’s shell is removed and the egg is rinsed dry and clean, measure and weigh the egg. Record the dimensions of each egg in a table.

Potato:

1. Lay out three watch glass.

2. Slice the potato in three parts lengthwise.

3. Place each slice onto a watch glass and make a hole in the middle of each slice. NOTE: the hole does not have to cross the slice!

4. In the first slice hole, don’t put anything. The second fill it with NaCl and the third with distilled water.

5. Left this preparation 30 minutes and make note of what is happening




RESULTS:

QUESTIONS:

Egg experiment:

1. What is happening when the shells are soaking of acetic acid?

2. Write the results of de dimensions and weigh of the egg before and after immersing it in distilled water. Write and draw a simple diagram of the water direction.

Potato experiment:

3. Explain the results of this experiment.

4. Why have we left the first slice without any treatment (salt or distilled water)?


5. Which are the dependent and independent variables?