Osmosis is the process by which water enters our tissues. All of our cells are surrounded by a membrane that selectively allows in anything the cell needs but prevents unwanted molecules from entering. An egg also has a membrane surrounding it so we can use it to represent a cell and see how osmosis works.
What does the egg represent in the osmosis lab?
The shell-less egg will represent a cell and its selectively permeable membrane. You will remove the shell of the egg by soaking the egg in vinegar. The egg shell is made up of the mineral calcium carbonate. Calcium carbonate dissolves in acids such as vinegar.
Why are eggs good materials for demonstrating the process of osmosis?
The egg is not a single animal cell. However the egg's membrane is selectively permeable, so it is a good model to show osmotic effects in animal tissue.
How does osmosis occur in an egg?
(The movement of water across a membrane is a special version of diffusion called osmosis.) When an egg is soaked in a solution in which the concentration of water is higher than that inside the egg, water moves from the outside solution, across the membrane and into the egg.
Why does an egg shrink in salt water osmosis?
So when you put an egg in water only, water flows in through the membrane making the egg expand. The egg in the salt water shrunk. This is because the solution outside the egg is more concentrated, so the water flowed out from the dilute solution to the concentrated solution.
Do eggs absorb water?
Eggs in their shell are pretty sturdy. Technically, a very small amount of water will be absorbed by the eggs, but unless you weighed them, you probably won't notice. I do have a small caveat, though: eggs are susceptible to smells, the chalky shell is pretty permeable.
What is the conclusion of the egg osmosis lab?
Discussion and Conclusion: While two of the solutions caused the eggs to increase in mass, syrup caused the egg to lose mass. This shows that the syrup was hypertonic to the solution inside of the egg, causing water to diffuse out of the egg to try and establish equilibrium.
What happens when you put egg in water?
If you put an egg in a cup of tap water, it will sink to the bottom. Why is this? Because the density of the egg is higher than the density of tap water, so it sinks. Density is the mass of a material per unit volume.
What happens to an egg when soaked in water?
Osmosis equalizes – or makes the concentration of water on both sides of the egg membrane the same. This means the egg will swell as the water moves inside and get larger. You can even color the inside of your egg if you soak it in some water with food coloring.
What was the purpose of placing the egg in vinegar?
Vinegar is an acid. Eggshells are made of calcium carbonate. If you soak an egg in vinegar the eggshell will absorb the acid and break down, or dissolve. The calcium carbonate will become carbon dioxide gas, which will go into the air.
Why would an egg shrink in water?
The water in the egg tends to go outside the egg if there is an area of higher solute concentration outside the egg. The water leaving the egg causes it to shrink. If the solution has a lower solute concentration, the egg will swell.
Why does an egg get bigger in distilled water?
By contrast, when an egg is treated with distilled water, or a dilute salt solution, the solute concentration is higher inside the egg than out, so the water moves into the egg, increasing its mass.
Do eggs absorb salt?
Salt absolutely penetrates the eggshell while boiling.
What happens when you put egg in water?
The egg will sink in regular tap water because the density of the egg is greater than the density of water. The egg's density is only slightly higher than water at 1.03 g/mL, but that is enough to make the egg sink.
How and why did the egg respond the way it did to the distilled water?
Inside the egg membrane is a concentrated solution of proteins and water. When the egg is soaked in distilled water, osmosis causes water to diffuse into the egg to equalize the concentration of water on both sides of the membrane, and the egg increases in volume.
What happens to an egg when soaked in water?
Osmosis equalizes – or makes the concentration of water on both sides of the egg membrane the same. This means the egg will swell as the water moves inside and get larger. You can even color the inside of your egg if you soak it in some water with food coloring.
What was the purpose of placing the egg in vinegar?
6. What was the purpose of placing the egg in vinegar? The vinegar solution was only used to remove the shell off the egg.
How much did the mass of an egg decrease after it was removed from the syrup solution?
The mass of the egg had decreased some 30 grams after it the egg was removed from the syrup solution. The mass of the egg 2 was smaller than the mass of egg1.
What are the cells in an egg called?
In this osmosis egg experiment, you will explore chemical reactions, plasma membrane, and osmosis. Eggs are specialized cells called gametes. Eggs have a membrane and a hard outer covering that function to protect the developing embryo and behave similarly to a cell’s membrane.
Why is the plasma membrane known as a semi-permeable membrane?
Semi-permeable membranes allow some things to pass through the membrane and don’t allow others.
What happens to a cell surrounded by water?
We were able to test three different eggs in three different solutions to see if the eggs gained or lost weight. The weight was caused by the movement of water across the membrane (either into or out of the egg). The results were dramatic.
Does vinegar make an egg rubberized?
As mentioned above, the vinegar reacts with the components of the shell and causes the shell to disappear. This leaves the membrane behind and you get a rubberized egg.
Why do eggs have membranes?
An egg also has a membrane surrounding it so we can use it to represent a cell and see how osmosis works.
Why do eggs grow in water?
If you now put the egg in water, it will grow in size a lot more due to the much larger water concentration gradient across the membrane. If you add food coloring to the water you can see the process of osmosis in action as the coloured water passes into the egg. Water is known as hypotonic, ie. very dilute and contains more water than the egg.
Why does vinegar increase the size of an egg?
This is because the water in the vinegar can enter the egg through the membrane, moving from the higher water concentration in vinegar to the lower concentration in the egg.
How long do you leave uncooked eggs in vinegar?
Weigh the uncooked eggs and carefully place them into a large glass of vinegar, cover and leave for 2 days. Remove the eggs and rinse gently under the tap. All of the shell should be gone by now (you can wipe off little bits still left over). Weigh the egg again.
How does osmosis work?
In this case, water moves around to different areas based on a concentration gradient, i.e. solutions which have different concentrations of dissolved particles ( solutes) in them. Water always flows to the area with the most dissolved solutes, so that in the end both solutions have an equal concentration of solutes. Think about if you added a drop of food dye to a cup of water – even if you didn’t stir it, it would eventually dissolve on its own into the water.
Why is osmosis important?
They all rely on osmosis: the diffusion of water from one place to another. Osmosis factors heavily in each of these processes and is an important force for keeping every single cell in your body healthy. Osmosis is hard to see without a microscope.
How to make sugar water?
Prepare three different sugar-water solutions as follows, labeling with sticky notes: Glass 1: Label “hypertonic”. Pour in one cup of corn syrup. Glass 2: Label “isotonic”. Add 1 ½ tablespoons corn syrup to the one cup measuring cup, and fill the remainder with distilled water.
How long does it take for an egg to sit in the refrigerator?
Put the three glasses in the refrigerator and allow to sit for 24 hours. 3. Gently holding the egg in the glass, pour out the old vinegar. Replace with fresh vinegar, and let sit in the refrigerator for another 24 hours. Repeat this process until the shells are fully dissolved and only the membrane remains.
What is the membrane that separates the different solutions?
In biological systems, the different solutions are usually separated by a semipermeable membrane, like cell membranes or kidney tubules. These act sort of like a net that keeps solutes trapped, but they still allow water to pass through freely.
How to keep eggs from floating in glass?
Pour in enough vinegar to cover each egg. Bubbles will start to form around the egg, and it’ll float up. To keep it submerged, put a butter knife in the glass to hold it down. 2. Put the three glasses in the refrigerator and allow to sit for 24 hours. 3.
Why do we need water in our body?
Every cell in your body needs the right amount of water inside of it to keep its shape, produce energy, get rid of wastes, and other functions that keep you healthy.
How long to refrigerate eggs in a beaker?
Place 3 eggs into separate beakers. Cover each egg with vinegar. Refrigerate for 24 hours.
How long does it take for eggs to be removed from a beaker?
After 24 hours , remove the eggs from the beakers.
What is the independent variable of the egg?
The independent variable was the substance (coffe and corn syrup). The dependent variable was the weight of the egg (s). The controlled variables were: temperature of liquid, shape of egg and amount of liquid.
Objective of The Experiment
Introduction
- Osmosis is a process whereby water or any fluid moves from the area of less concentration of dissolved particles to a region of high concentration of dissolved particles across a semi-permeable membrane. Due to difference in the concentration gradient, dissolved particles are able to move across a semi-permeable membrane from the area of high concentration to that o…
Experimental Procedure
- Three eggs were put in vinegar and left there for three days. Three days after, a demineralized egg was removed from vinegar and cleaned using tap water. The mass of the cup to use in the experiment was recorded. The cleaned egg was carefully put into the clean cup and weighted. The mass of the egg itself was calculated and recorded. The cup was then filled with three-quarters …
Discussion
- The results of the experiment show the increased mass of the egg being soaked in vinegar. This is explained by the fact that vinegar has a higher concentration of water as compared to the egg and therefore through osmosis water moved from highly concentrated area (vinegar) into the egg which has lower concentration of water molecules. This made the egg increase in its weight fro…
Conclusion
- Water molecules shifted from the area of high gradient to the area of less gradient. For example, when the egg was placed in corn syrup, water moved out of egg thereby reducing the weight of the egg. The reverse is true for distilled water. In conclusion, the objective of the experiment was met since the process of osmosis was examined.
Questions
- What are some potential sources for errors in the experiment? What can be done to minimize those? An error might have occurred due to incorrect measurements of the size and weight of the egg. Recor...
- Based on this lab, what would you expect to happen to the cells of a celery stick if you placed it in a hypertonic solution and why? We expect the cells of a celery stick to be deprived off wat…
- What are some potential sources for errors in the experiment? What can be done to minimize those? An error might have occurred due to incorrect measurements of the size and weight of the egg. Recor...
- Based on this lab, what would you expect to happen to the cells of a celery stick if you placed it in a hypertonic solution and why? We expect the cells of a celery stick to be deprived off water s...
- Dishonest shellfish dealers actually place their oysters and clams in a hypotonic solution. Why? This happens because they want their oysters and clams to weigh more than they actually do. The thin...
