Egg Diffusion Lab

Egg Diffusion Lab

In this experiment, we were observing how an egg's internal environment changed as its external environment changed.  After removing the egg's shell by soaking it in vinegar, we left the eggs either in a sugar/ water solution and deionized water, then, after around 48 hrs of soaking, measured that change in both mass and circumference in each egg.

 When the egg was placed in deionized water, it grew slightly (.176%)  in mass, and there was no change in circumference, most likely because we had previously soaked in tap, not deionized water.  The egg most likely grew a little because inside the egg's membrane there was a higher amount of sugar (solute) and less solvent (water) than outside the egg, which was all solvent. Since the sugar in the egg was too big to diffuse through the egg's membrane, the egg took more water in through passive diffusion, because the water was moving from high concentration to the low concentration inside the egg's membrane.  

When the egg was placed in sugar water, a hypertonic solution,  it's mass decreased by 51.7% on average and its circumference decreased by 23.67%.  This is because the sugar water surrounding the egg contained more solute than the egg, and so to balance the concentrations, water was released from inside the membrane in order to make the sugar concentrations inside higher, leading to decreases in both mass and circumference.  

A egg cell's internal environment changes in both mass and circumference as it's external environment changes, in order to balance the concentrations of solutes and solvents. When we added the vinegar around the egg, I think that the egg's mass and circumference changed because the egg might have taken in some of the vinegar solution. When we put the egg in water, (tap water) the egg might have also taken in some of the contaminants in the water. When we put the egg in sugar, it shrunk because it let out some out the water inside in order to balance the concentrations  of the internal and external environments.

This lab demonstrates the biological principle of diffusion and solutes and solvents by showing us a real life example. Since the sugar was too big to diffuse through the cell's membrane, the cell lost and gained water. When the egg was placed in a solution with more solute than inside the egg, it shrunk, because the sugar water was a hypertonic solution. When the egg was placed in the deionized water, which had more solvent than inside, it grew slightly, because the deionized water was a hypotonic solution.

Fresh vegetables are sprinkled with water at markets because water will diffuse into them making them fresher and plumper. When salt is used on roads and get near the plants on the side of the road, it kills them because the water diffuses out of the plant, and shrivels the plant, and so it dies.

Based on this experiment, I would want to test celery to see how leaving in in different concentrations of water, sugar, and salt would affect it.  It would be relatively easy to detect changes in the celery, as they are straight. We could also try this experiment with vegetables such as lettuce and spinach.