Egg Osmosis Lab

By: Lexie Ryan

When the egg was placed in vinegar for 3 days, the egg grew
in size. This phenomenon was because of osmosis, which is
the diffusion of water molecules through a selectively
permeable membrane. The egg is a single cell that has a
semi-permeable membrane, also known as a Phospholipid
Bilayer. This membrane allows some things through while
keeping others out. The vinegar is a hypotonic solution,
meaning that its solute concentration is lower than the egg.

Day 1 Egg placed in Vinegar

For this lab, we measured the unaltered egg, which came out to
be 61.2g. We then placed the egg in a 200 mL beaker of vinegar
and covered the top of the beaker with foil. It was left in the
classroom for 3 days. When I returned, the egg had a noticeably
yellow tint and small bubbles on it. The bubbles showed a symbol
for a chemical reaction, showing us that most of the calcium shell
had dissolved. After our observations, we weighed the egg. The
eggs mass was 86.6g, a much larger mass than before. 155 mL
of vinegar was left in the beaker, a 29% drop. The egg grew 29%
The top chart shows the mass of the egg over the
due to the hypotonic solution of the vinegar. Due to the solute
course of the lab. The bottom chart shows the
concentration being lower than the egg, the water moves into the
egg in order to maintain homeostasis of a balance level of
changes in volume of each day from the initial
Day 4 Egg in Vinegar amount of 200 mL. Comparing these 2 charts, you
solvents and solutes. The result of this action was why the
amount of remaining vinegar was less than the starting amount of see that when the mass increases in the egg, the
vinegar. volume of the solvent decreases, and when the
mass of the egg decreases, the volume of the
solvent increases. If only using these to charts and
After the vinegar, we used the same egg and placed it in 200 mL beaker of syrup, no other data from the lab, you can easily infer
then covered it with foil. 1 day later we observed the egg. It was still yellow, which solvents where hypotonic, hypertonic, or
though there was less bubbles on the egg. Unlike the day before, the egg had a isotonic to the lab. If the remaining amount of
deflated look, like someone popped it with a needed. When we took the egg out Thin Layer of Water volume is less than the initial amount of volume,
of the syrup, it felt exactly the way it looked. The egg weighed 51.5g and 225 mL and the egg gained in mass, much like days 4 and
of syrup was left over in the beaker. In the beaker was also a thin layer of water
6, you see that the liquid was a hypotonic solution.
resting on top of the syrup. With this observation, we came to the conclusion that
If the solvent has a lower solute concentration than
the syrup is a hypertonic solution, meaning that the solute concentration was
the egg , then water is going to move into the egg,
higher than the egg. In order for the egg to be at an equilibrium state, water
causing it to swell/increase the mass and decrease
molecules moved across the Phospholipid Bilayer, hence the liquid layer on top
the amount of the solvent, to maintain homeostasis.
of the syrup. Because the egg lost liquids, the level of remaining water was
higher than the initial amount, and the egg appeared deflated. Day 5 Egg in Syrup

For the last day of the experiment, we once again used the same egg and put it
in a beaker of 200 mL of distilled water. After the egg spent one day in the
Day 5 Egg in distilled water, we took it out to observe it. The egg had less of a yellow tint than
distilled water the 2 previous days, and grew a considerable amount of size. The egg looked
full, much like a balloon filled with water. It was also to be noted that the egg was
sinking rather than floating like the previous 2 days. The egg was squishy, like a
rubber ball. The recorded mass of the egg was 92.2g and the left over water
amount was 150 mL. Once again, this quantitative and qualitative data shows
that the water was a hypotonic solution. With the solute concentration being
lower than the egg, osmosis occurred to maintain homeostasis. The 50 mL being
hacked of the initial amount and the increased weight of 40.7g to the egg shows
that the water was moved into the egg.