Osmosis

Osmosis Lab

Osmosis is the passage of water and other liquids through a semipermeable membrane. In metabolism, osmosis regulates the concentration of substances on both sides of the membrane.

Eggs contain a membrane through which osmosis can take place. In this experiment, you will determine whether water flows primarily in or out of an egg by observing changes in liquid level and in the size of the egg.

Source: Mehas & Rogers

Place an egg in a 250-mL beaker. Add enough vinegar to cover the egg. Let stand for three days to dissolve the shell.

Pour out vinegar and carefully rinse any remaining shell off egg, leaving the egg sac. Carefully transfer the egg, which now has no shell, to a clean 250-mL beaker.

Variation 1. Add water to completely cover the egg. Variation 2. Add vinegar to completely cover the egg. Variation 3. Add corn syrup to completely cover the egg. Variation 4. Add a salt-water solution to completely cover the egg.

Variation 1. Add water to completely cover the egg.

After you have the 4 variations.....

Measure the height of the liquid in the beaker and record it in your data table.

After 30 minutes, again measure the height of the liquid in the beaker. Record in your data table.

Label the beaker with the variation number. Cover it with plastic wrap. Leave overnight.

On the following day, measure the liquid height and observe the appearance of the egg and liquid.

Note any evidence of layering in the liquid. Record the information in your data table.

Record your observations on the heights of the liquid and the appearance of the egg and the liquid on your data table. Answer the questions on your lab sheet.

Osmosis Lab Sheet

Source: Mehas & Rodgers

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