Osmosis Eggsperiment

A type of passive transport is that of osmosis. Osmosis is the movement of water across a semi-permeable membrane. The process by which osmosis occurs is when water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration. The direction of osmosis depends on the relative concentration of the solutes on the two sides. In osmosis, water can travel in three different ways.
If the molecules outside the cell are lower than the concentration in the cytosol, the solution is said to be hypotonic to the cytosol, in this process, water diffuses into the cell until equilibrium is established. If the molecules outside the cell are higher than the concentration in the cytosol, the solution is said to be hypertonic to the cytosol, in this process, water diffuses out of the cell until equilibrium exists. If the molecules outside and inside the cell are equal, the solution is said to be isotonic to the cytosol, in this process, water diffuses into and out of the cell at equal rates, causing no net movement of water.
In osmosis the cell is selectively permeable, meaning that it only allows certain substances to be transferred into and out of the cell. In osmosis, the proteins only on the surface are called peripheral proteins, which form carbohydrate chains whose purpose is used like antennae for communication. Embedded in the peripheral proteins are integral proteins that can either be solid or have a pore calledchannel proteins. Channel proteins allow glucose, or food that all living things need to live, pass through.

 

Hypothesis:
In the syrup solution, water  molecules will move  out of the egg making it shrink.

Materials:
The materials used in this lab were 2 fresh eggs in the shell,  2 cups of water, graduated cylinder, 2 large cups, 1 small cup, white vinegar, Karo syrup, tap water, pencil, paper, apron, safety glasses, press and seal, masking tape, baking sheet, tongs, scales, osmosis lab sheet, and computer.

 

Methods:
On day 1, measure  both the eggs with the shell. Label 1 cup  vinegar, and then use the graduated cylinder to measure 2 cups of vinegar to  put in the labeled cup. Place both eggs in the solution (place a small cup on top of the eggs, if necessary) then cover. Let the eggs stand for 24 hours or more to remove the shell.

 

On day 2, record the observations of what happened to the eggs in the vinegar solution. Carefully, remove the eggs from the vinegar, gently rinsing the eggs off in water. Clean the cups used for the vinegar solution preparing them for the syrup solution, and then label the 2 cups  syrup. Before the eggs are placed in the syrup solution record the measurements of both eggs then put it on the datasheet. After that has been done, place the eggs in the cup, pouring enough syrup to cover the eggs, cover them loosely and let them stand for 24 hours.

On day 3, record the observations of the egg from the syrup solution. Carefully, remove the eggs from the cups, gently rinsing the syrup off of the eggs.. Clean the two cups used in the syrup solution, preparing them for the water solution. Before the eggs are placed in the water solution record the measurements of both eggs then put it on the datasheet. After that has been done, measure out 2 cup of water for each cup. Place the eggs in the water solution, cover and let stand 24 hours.

On day 4, record the observations of the egg from the water solution. Carefully remove the eggs from the cups, gently rinsing them off. Measure both of the eggs.

Table 1- Egg 1 Data

	Egg mass before added into the solution (g)	Egg mass after added into the solution (g)	Observations
Vinegar	75.6 g (with shell)	113.5 g (without shell)	Before the egg was added into the vinegar, it was large, but the after effect was that the egg increased in size. After one day, the shell was completely removed.
Syrup	113.5 g	61.0 g	When the egg was removed from the syrup, it had shrunk and it was softer than before it was added into the solution
Water	61.0 g	100.3 g	When the egg was removed out of the water, the color was a pale yellow. The water had entered into the egg, because the egg was larger in size before it was added into the water.

Table 2- Egg 2 Data

	Egg mass before added into the solution (g)	Egg mass after added into the solution (g)	Observations
Vinegar	62.7 g (with shell)	89.1 g (without shell)	Egg 2s’ mass was less than egg 1s’ mass before and after it was added into the vinegar solution. The mass had increased 26 grams with the shell off.
Syrup	89.1 g	53.1 g	The mass of the egg had decreased 36 grams after  the egg was removed from the syrup solution. The mass of the egg 2 was smaller than the mass of egg1.
Water	53.1 g	110.2 g	The mass of egg 2 had increased   57 grams after being added into the water solution. The mass of egg 1, was smaller than the mass of egg 2.

The result is that the egg increased in size and mass when placed in white vinegar solution and tap water solution, but decreased in size and mass when placed in syrup.

Based on the data collected and the results of the experiment, the hypothesis was correct. The egg appeared shriveled after removing it from the syrup because of the movement of water out of the egg. The syrup solution was hypertonic so water moved out of the egg from an area where water was more concentrated to the outside of the egg where water was less concentrated due to the high amount of sugar or solute. Whenever the egg was transferred from the syrup to the distilled water, the concentration of water outside the shriveled egg was greater than the water concentration inside the egg; therefore, water moved into the egg until equilibrium was reached. At that point, movement into and out of the egg continued with no net movement of water molecules.

1. In which direction did the water molecules move when the egg was placed in the water?     The water molecules moved into the egg.
2. On what evidence do you base this?The molecules moved in, because the size of the egg increased
3. How do you explain the volume of liquid remaining when the egg was removed from the syrup? Since, the cell is selectively permeable, it only allowed a certain amount of the syrup to be present in the cell, and just enough to shrink it and also equilibrium was reached.
4. When the egg was placed in the water after being removed from the syrup in which direction did the water move?The water moved into the egg.
5. Why did the water molecules travel better inside the cell than the syrup molecules? The water molecules traveled better into the cell because smaller molecules travel better than other larger molecules.
6. What was the purpose of placing the egg in vinegar? The vinegar solution was only used to remove the shell off the egg.