Shell Removal

How To Remove An Egg’s Shell Without Breaking the Egg

The shell surrounding a chicken egg is composed of a chemical called calcium carbonate, which will react with acids. Vinegar is an acid called acetic acid. The chemical reaction that occurs when calcium carbonate and vinegar combine is called a chemical decomposition reaction.

The word equation for this chemical decomposition reaction is:
calcium carbonate + acetic acid yields calcium carbonate + water + carbon dioxide.

2. Fill a 1-quart (1-liter) jar about three-fourths full with white vinegar. Note: The jar must be large enough for the egg to be placed inside.

  • Place the egg in the  jar of vinegar.
  • Record your observation of the egg after placing it in the jar of vinegar.

3. Make observations at least once daily until it is obvious that the shell is gone. This usually takes two to three days. Diagrams can be used as observations.

Date Observation
4/15/09 1. Physical Properties of a Raw Egg:
Circumference measurement:5.5 cm shell- white, hard2. Raw Egg in Vinegar:Egg sinks to bottom of jar.Bubbles form on the surface of the shell.
4/16/09
4/17/09 Naked Egg:measurement:physical properties:

4. Remove the naked egg from the vinegar and wash it with tap water.

  • Use the measuring tape to measure the largest part of the egg as before.
  • Record your observation of the naked egg, including how it feels, looks, etc………..

Caution: If you decide to test how bouncy the egg is, be sure to have a tray under it. The membrane surrounding the egg can break and the inside of the egg is fluid (able to flow–liquids and gases are fluids).

WHAT’S HAPPENING?

RAW EGG: The shell is made of calcium carbonate, which it limestone. The calcium carbonate reacts with the vinegar, which is acetic acid and one of the products is carbon dioxide gas. The bubbles on the surface of the egg shell are filled with carbon dioxide gas. These bubbles cause the egg to be buoyant (the ability to float).

The word equation for this chemical reaction is:

calcium carbonate + acetic acid yields calcium carbonate + water + carbon dioxide.

NAKED EGG: The naked egg (egg without the shell) is surrounded by a membrane which is rubbery as a result of the vinegar. The “naked” egg is larger than when it was “clothed” with its limestone shell. This is because vinegar is a mixture of water and acetic acid. The water moves through the egg’s membrane by a process called osmosis.

PART 2: Dissecting a Naked Egg

1. Repeat part 1 preparing a second “naked egg.”

2. When the egg’s shell has been chemically removed by the vinegar, place the “naked” egg in a tray. Use scissors to remove the membrane surrounding the egg.

 

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You can remove the shell from a raw egg without breaking the egg by placing the egg in vinegar. Not only will the shell be removed, but the egg will get larger.

Discover for Yourself

PART 1

1. Observe a raw egg and record its physical properties in a data table, such as the one shown.

Use a sewing measuring tape to measure the distance around the largest part of egg. Record the measurement in the data table.