Egg Osmosis Lab
Cells have an outer covering called the cell membrane. This membrane is semi-permeable; it has tiny pores or holes that allow objects to move across it. The cell membrane controls what moves in and out of the cell. Food and oxygen move into cells across the cell membrane through the process of diffusion. Diffusion is movement of a substance from an area of high concentration to an area of low concentration. Osmosis is a special type of diffusion; it is the diffusion of water across a semi-permeable membrane. Osmosis occurs when water moves from an area where it is more concentrated to an area where it is less concentrated.
In this lab you will be using an egg with the shell removed. The shell-less egg will represent a cell and its semi-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. During this process it releases the gas carbon dioxide. After the shell has been dissolved, only the membrane will remain around the egg.
Safety notes:
1. Raw eggs can carry salmonella (harmful bacteria). Be sure to wash your hands after handling the eggs.
2. Handle your egg very carefully so that it does not break
Procedure:
Day One:
- Take your egg and place it in a beaker with vinegar. Make sure that your egg is fully submerged
Day Two:
- Clean your egg with the hard shell removed so only the soft semi-permeable membrane remains. Remember that your egg is very fragile at this point!
- Measure the mass of the egg alone.
- Submerge the egg in 250ml of water and leave overnight.
Day Three:
- Remove the egg from the water and record the water level, what do you notice?
- Measure the mass of the egg alone
- Place the egg in 250ml of corn syrup , dishwasher detergant or another fluid approved by Mr. Hambly
Day Four:
- Remove the egg from the fluid and record the fluid level, what do you notice?
- Measure the mass of the egg alone
** From your observations what has happened to the egg over the past four days?
In this lab you will be using an egg with the shell removed. The shell-less egg will represent a cell and its semi-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. During this process it releases the gas carbon dioxide. After the shell has been dissolved, only the membrane will remain around the egg.
Safety notes:
1. Raw eggs can carry salmonella (harmful bacteria). Be sure to wash your hands after handling the eggs.
2. Handle your egg very carefully so that it does not break
Procedure:
Day One:
- Take your egg and place it in a beaker with vinegar. Make sure that your egg is fully submerged
Day Two:
- Clean your egg with the hard shell removed so only the soft semi-permeable membrane remains. Remember that your egg is very fragile at this point!
- Measure the mass of the egg alone.
- Submerge the egg in 250ml of water and leave overnight.
Day Three:
- Remove the egg from the water and record the water level, what do you notice?
- Measure the mass of the egg alone
- Place the egg in 250ml of corn syrup , dishwasher detergant or another fluid approved by Mr. Hambly
Day Four:
- Remove the egg from the fluid and record the fluid level, what do you notice?
- Measure the mass of the egg alone
** From your observations what has happened to the egg over the past four days?