Naked Egg Experiment
We have been enjoying the Christmas season and events. Packing in all sorts of day trips, get-togethers, sweat sips, and delicious NAVIDAD inspired treats into our days.
But still we must also prioritize our studies. Minime has expressed interest in marine biology, and so science features high on the that priority list.
Last week, we conducted a laboratory study at home to discover the features of the cell.
Fun fact: the unfertilized egg is the largest single cell. The ostrich egg holds the utmost superlative title.
No ostrich eggs in our refrigerator, and so the humble hen egg had to do. I tend to favour free-range eggs. I don't know why but that lovely orange yolk simply tastes better. However for this experiment, you will probably want to get some conventional eggs; they generally have white shells and allow for better observations as it dissolves.
Equipment and Supplies
3-4 white eggs
3-4 C white vinegar
clear glass container
corn syrup
food colouring
a few days and space on the counter
Click in for the directions.
From our studies ...
Initial observation
The eggs are oval and white. They have a hard opaque shell. The vinegar is a clear liquid. It has a strong smell that tickles the nose and it tastes sour.
Observation when the eggs are first observed
I see tiny bubbles floating to the surface.
Observation after 2 minutes
I see bubbles flowing to the surface and sticking to the egg
Observation at 10 minutes
The egg is completely covered in bubbles and is almost standing up in the vinegar. There are bubbles on top of the liquid.
Day 1
The egg is still covered in bubbles and has floated to the top. There is now a slight yellow to the egg. There is froth on top of the vinegar.
Day 2
The egg by itself has gone a deeper yellow than the four eggs together. All the eggs have expanded.
Day 3
No noticeable change from the day before, but starting to smell bad.
Summary Observation
They didn’t float at the beginning but floated at the end. They became less dense to do so. Their shells partially dissolved, down to a membrane, and became semi-transparent. The eggs expanded.
Labelled Cell
The naked egg submerged in coloured water turned blue.
The food colouring must have passed through the cell membrane without destroying the membrane because the egg still has the same structure as the original naked egg.
The naked egg in corn syrup lost its structure, went flat, and turned the colour of the corn syrup. The corn syrup must have caused a reaction that weakened the cell membrane.
Conclusion
According to Molecular Biology of the Cell, 4th Edition, unfertilized eggs are not just a model of a cell, but indeed a single cell. The vinegar dissolved the hard shell and left the cell membrane intact. Nutrients must pass through the cell membrane and into the cell. Waste products must pass through the cell membrane and out of the cell. The food colouring and the corn syrup demonstrated the process(es). The process(es) here is called diffusion and possibly osmosis. When you broke the naked egg open, you could see the nucleus, the cell membrane, and the cytoplasm. The yolk was the nucleus. The cytoplasm was the egg whites, and the cell membrane was what was left of the shell. I think I got good results, but they might have been better if I had left the naked eggs in the food colouring and corn syrup for longer. Also having a separate container for each egg would have increased surface area and allowed more shell to dissolve.
Source: Johnson, Alberts B, and A J Lewis. “Eggs.” In Molecular Biology of the Cell. 4th Edition. New York: Garland Science, 2002.
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