How to Dissolve an Eggshell

Dissolving the Eggshell

Gather your materials. For this experiment you will need a fresh, uncooked egg, a drinking glass, a dissolving solution such as white vinegar or a cola beverage, and 4-5 days of patience. The drinking glass needs to be large enough for the egg to touch the bottom without touching the sides of the glass. You can also use a plastic cup or container to hold the egg, but clear containers allow you to observe the experiment over time. Use a fresh egg because an older egg will float in the liquid. Before you begin, examine your uncooked egg for cracks.

Place the egg in the glass and submerge with vinegar. Gently place the egg in the bottom of the glass taking care not to crack it. Pour enough vinegar (or cola) over the egg until it is completely submerged in the liquid. The chemical reaction between the acetic acid in the cola and the calcium carbonate in the eggshell causes the shell to dissolve.

Cover and refrigerate the egg for 24 hours. Cover the top of the container with foil or plastic wrap and place it on a shelf of the refrigerator where it will remain undisturbed. Keep it out of the way so it doesn't get knocked around.

Replace the vinegar in the cup after 24 hours. After the first day, you should see the frothy residue of the shell on the surface of the liquid. You will also see that parts of the shell still remain on the egg. The shell takes at least 2 days to fully dissolve and may take up to 3. Gently pour out the vinegar taking care to keep the egg from falling out of the container. Carefully roll the egg back down to the bottom of the container and refill it with vinegar.

Leave the egg undisturbed for at least 24 more hours. Place the egg back in the refrigerator and leave it alone. After at least another 24 hours, remove the egg to check its progress. If there are no white spots or areas that look like shell left on the egg, the dissolving process is complete. Gently pour out the vinegar and catch the naked egg in your hand. See how it feels.

Experimenting with the Naked Egg

Test the strength of the membrane. Carefully remove the egg from the vinegar. You may notice that it feels quite rubbery. To test the strength of the membrane, try dropping the egg on the table and see if it bounces. Start with just one inch above the table and then increase the height by an inch at a time. At a certain height, the egg will break. Do this activity outside or lay down newspaper before experimenting.

Grow the egg with water. The membrane of the egg is permeable to liquid, meaning that water can pass through into the egg. The contents of the inside of the egg contain about 90% water. If you put the egg in a cup that is 100% water, the water will pass through the membrane to equalize the amount of water inside the egg due to a process called osmosis. As the water moves into the egg, the egg swells in size. Add food coloring to the cup of water to color your egg. You can also shrink the egg after growing it, if desired.

Shrink the egg with corn syrup. Using the same properties of osmosis, you can shrink the egg by placing it in a solution with very little water. Place the egg in a container full of corn syrup. This time, water will pass out of the egg to equalize the amount of water on each side of the membrane. As the water leaves the egg, it will shrivel and shrink. You can put the egg back into a glass of water to grow it again after shrinking it, if desired.