It is possible to corrode the shell of an egg leaving the membrane completely intact. In this way you will be able to carry out the so-called "naked egg experiment". The process is simple, takes a few days, and can be done very easily using everyday objects. The eggshell is mostly made up of a compound called calcium carbonate, which dissolves when exposed to an acid such as vinegar. During the chemical reaction, bubbles of carbon dioxide will be released on the surface of the egg. It is a simple and safe scientific experiment to carry out at home.
Steps
Part 1 of 2: Corroding the Egg Shell
Step 1. Get everything you need
For this experiment you will need a fresh raw egg, a glass beaker, a corrosive substance (such as white vinegar or a cola drink) and 4 or 5 days of patience. The glass must be large enough for the egg to touch the bottom, but not the sides.
- You can also use a plastic cup or container, but the glass allows you to better observe the progress of the experiment.
- Less fresh eggs tend to float in liquids, so it's important to use a freshly picked egg.
- Before starting, examine the egg to see if it has any cracks.
Step 2. Put the egg in the glass and submerge it with the vinegar
Gently place the egg in the bottom of the glass, avoiding breaking it. Completely submerge it in vinegar (or cola).
The chemical reaction that occurs between the acetic acid of the cola and the calcium carbonate of the shell will cause it to corrode
Step 3. Cover the egg and keep it in the fridge for 24 hours
Cover the container with a sheet of aluminum foil or cling film and place it on a shelf in the refrigerator where it won't bother you. Place it on the back to prevent it from being slammed or hit.
Step 4. Replace the vinegar after 24 hours
After a day, on the surface of the liquid you should observe the residues of the shell, which will have taken on a foamy consistency. You will also notice that some parts of the shell will still be attached to the egg. Consider that for complete corrosion you have to wait at least 2 days, sometimes even 3.
- Gently pour the vinegar into the sink, preventing the egg from falling out of the glass.
- Place the egg once again in the bottom of the glass with extreme care and fill it again with vinegar.
Step 5. Do not touch the egg for at least another 24 hours
Put it back in the refrigerator and don't touch it. When at least another 24 hours have passed, take it out of the fridge to review the progress of the experiment. If you no longer see any white spots or areas, then there is no shell left and the corrosion process has come to an end.
Gently pour the vinegar into the sink and grab the naked egg with one hand to observe the sensations you feel from a tactile point of view
Part 2 of 2: Experimenting with the Naked Egg
Step 1. Test the resistance of the membrane
Remove the egg from the vinegar carefully. You will see that it will be rubbery and elastic to the touch. To examine the resistance of the membrane, try dropping the egg on the table and see if it bounces. Start at a height of only 3cm and then gradually increase it by 3cm at a time.
Upon reaching a certain height, the egg will break. Do this procedure outdoors or spread some newspaper on the table before doing the experiment
Step 2. Make the egg dilate with water
The egg's membrane is permeable to liquids, so water can get inside. The egg content is made up of approximately 90% water. If you put it in a cup full of water, the liquid will pass through the membrane in order to equal the amount of water inside the egg. This phenomenon will take place through a process called osmosis. The egg will dilate as the water is absorbed.
- Pour some food coloring into the cup to color the egg.
- If you want, you can also shrink the egg after making it dilate.
Step 3. Shrink the egg with corn syrup
Using the same properties as osmosis, you can shrink the egg by placing it in a solution with very little water. Place the egg in a container filled with corn syrup. This time the water will come out of the egg to equal the amount of liquid present on each side of the membrane. As the water escapes, the egg will wrinkle and shrink.
If you want, you can put the egg back in a glass of water to make it dilate again after letting it shrink
Warnings
- If the egg is shaken or struck, the thin membrane under the shell could break. This will ruin the experiment, as the vinegar will mix with the contents of the egg.
- Do not eat the egg after using it for experiments. The shell protects it from contamination. When removed, consuming the egg can be dangerous.
