Osmosis & Diffusion in an Egg

Objective:
In this investigation, you will use a fresh hen's egg to determine what happens during osmosis & diffusion across membranes.

Materials: (per lab group)
1-2 fresh hen eggs in their shells, masking tape & marker, distilled water, clear sugar syrup (Karo, for example), vinegar, clear jar with lid, tongs, electronic balance, paper towels, paper, pencil

Procedure:

Day 1   

1. Label the jar with your lab group & the word "vinegar".
2. Mass the egg with the electronic balance & record in the data table.
3. Carefully place the raw egg into the jar & cover the egg with vinegar.
4. Loosely re-cap the jar & allow the jar to sit for 24 to 48 hours until the outer calcium shell is removed.

Day 2   

1. Open the jar & pour off the vinegar.
2. Use tongs to carefully remove the egg to a paper towel & pat it dry.
3. Record the size & appearance of your egg in your data table.
4. Mass the egg on an electronic balance & record.
5. Clean and re-label the jar with your lab group & the word "distilled water".
6. Carefully place the egg into the jar & cover the egg with distilled water.
7. Loosely re-cap the jar & allow it to sit for 24 hours.

Day 3   

1. Open the jar & discard the distilled water.
2. Use tongs to carefully remove the egg to a paper towel & pat it dry.
3. Record the size & appearance of your egg in your data table.
4. Mass the egg on an electronic balance & record.
5. Clean and re-label the jar with your lab group & the word "syrup".
6. Carefully place the egg into the jar & cover the egg with clear syrup.
7. Loosely re-cap the jar & allow it to sit for 24 hours.

Day 4   

1. Open the jar & pour off the syrup.
2. Use tongs to very carefully remove the egg & rinse off the excess syrup under slow running water.
3. Pat the egg dry on a paper towel.
4. Record the size & appearance of your egg in your data table.
5. Mass the egg on an electronic balance & record.
6. Clean up your work area & put away all lab equipment.

Data:

Questions & Conclusion:

1. Vinegar is made of acetic acid & water. Explain how it was able to remove the calcium shell.

2. (a) What happened to the size of the egg after remaining in vinegar?

   (b) Was there more or less liquid left in the jar?

   (c) Did water move into or out of the egg? Why?

3. (a) What happened to the size of the egg after remaining in distilled water?

   (b) Was there more or less liquid left in the jar?

   (c) Did water move into or out of the egg? Why?

4. (a) What happened to the size of the egg after remaining in syrup?

   (b) Was there more or less liquid left in the jar?

   (c) Did water move into or out of the egg? Why?

5. Was the egg larger after remaining in water or vinegar? Why?

6. Why are fresh vegetables sprinkled with water at markets?

7. Roads are sometimes salted to melt ice. What does this salting do to the plants along roadsides & why?