Bouncy Raw Egg
This experiment was to show us osmosis in living cells.
We used a quail's egg that is enclosed in a thin membrane that is protected by a shell made of calcium carbonate.
The Experiment
Place the quail's egg into a beaker and fill the beaker with dilute hydrochloric acid.
Bubbles of colourless gas and white froth was observed to have formed and hence we can infer that the egg shell was reacting to the dilute hydrochloric acid and a gas was evolved.
Soak the egg in the acid for 15 minutes, stirring occasionally.
After about 15 minutes, pour away the dilute hydrochloric acid.
Then rinse the egg with water and examine it.
Next describe how the egg feels to the touch and record your observation.
Then measure and record the length of the egg.
Next fill half a beaker with water and place the egg inside.
After 30 minutes, remove the egg from the water and describe its hardness and record the observation.
Then measure and record the length of the egg.
Put the egg back in water and leave it for 24 hours.
Observe it again after 24 hours and describe its hardness and measure it and record both observations.
The dilute hydrochloric acid dissolved the egg shell. From the observations, the egg is soft and it grew after being put in the water. Hence we can infer the egg membrane lets water pass through.
Osmosis in living cells allows water to enter the cell but prevents the contents of the cells from escaping.
Osmosis absorbs water into the cell, which the cell needs to survive.
The egg membrane is semi-permeable.
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