Name Date Period

The Incredible Egg Demonstration

Purpose: To demonstrate the process of osmosis.

Materials: 2 raw eggs 2 large beakers or cups white vinegar distilled water corn syrup

Procedure: Day One: 1. Place both eggs in the vinegar bath. 2. Wait 24 hours.

Day Two: 1. Take two eggs from the vinegar bath. 2. Gently run water over the eggs and rub the surface to remove as much of the shell as you can. 3. Weigh one of the eggs and record the mass in the data table under “initial mass – water”. 4. Place the egg in a beaker and label it “water” with labeling tape (include your initials on the tape). 5. Pour water into the beaker so it just covers the egg. 6. Weigh the second egg and record the mass in the data table under “initial mass - syrup”. 7. Place the egg in a beakers and label it “syrup” with labeling tape (include your initials on the tape). 8. Pour syrup into the beaker so it just covers the egg. 9. Place your beakers on the side lab tables.

Hypothesis: Circle the word that best completes the hypothesis:

1. If we place an egg in distilled water, then it will (expand OR shrink).

2. If we place an egg in syrup, then it will (expand OR shrink). Procedure (continued):

Day Three: 1. CAREFULLY pour the water off of the “water” egg. 2. Weigh the egg and record the mass under “final mass – water” in the data table. 3. CAREFULLY pour the syrup off of the “syrup” egg. 4. CAREFULLY rinse as much syrup off the egg as you can. 5. Weigh the egg and record the mass under “final mass – syrup” in the data table. 6. Calculate the change in mass (final mass – initial mass) and record it in the “Mass Change” column. Keep the +/- sign with your answer. 7. Write “expand” or “shrunk” in the appropriate column of the data table. Name Date Period

Observations/Data:

Egg Initial Mass Final Mass Mass Change Expand/Shrunk

Water

Syrup

Analysis and Conclusions:

1. Is the egg membrane selectively permeable? (explain your answer)

2. Why did water move into the “water” egg? (draw a diagram to explain what is happening)

3. Is the water a hypotonic, hypertonic, or isotonic solution? How do you know?

4. Why did water move out of the “syrup” egg? (draw a diagram to explain what is happening)

5. Is the water a hypotonic, hypertonic, or isotonic solution? How do you know?