Egg-cellent Chemistry: How to Marble Eggs
Decorating eggs is a fun and memorable way to illustrate scientific concepts and make real-world connections. This egg-speriment is appropriate for either the kitchen at home or the laboratory at school.
Perform this activity in accordance with established laboratory safety practices, including appropriate personal protective equipment (PPE). Ensure that students understand and adhere to these practices. Know and follow all school district guidelines for the disposal of laboratory wastes. Read the cautions below before performing the activities.
Handling eggs carries a risk of exposure to harmful Salmonella bacteria, which can grow on the exterior as well as the interior of eggs. To reduce the risk of exposure to bacteria, boil the eggs thoroughly until the yolk and white are firm. To reduce risk of growing bacteria, keep the eggs refrigerated at or below 40° F (4° C) until needed.
Food coloring and dyed eggs can stain hands, clothing, upholstery, and wood. To prevent staining your hands with food coloring, use disposable gloves.
Topics covered: properties of water, polarity, properties of soap
Foam shaving cream is primarily composed of air and soap. Soap is an amphipathic substance, which means that its molecules have both a hydrophilic (water loving) end and a hydrophobic (water fearing) end. Because of this, soap can combine with water and also with many oils. Shaving cream’s hydrophobic end means that when you drop food coloring (a hydrophilic substance) onto shaving cream, the coloring does not spread.
When you place an egg on top of the shaving cream and the colored pattern, the food coloring adheres to the egg, causing the colored pattern to transfer permanently to the egg.
- Disposable Gloves
- Foam Shaving Cream
- Tall-Sided Container (similar to a pie tin)
- Food Coloring or FD&C Red #40, FD&C Blue #1, FD&C Green #3, and FD&C Yellow #5
- Plastic Spoon
- Hardboiled Eggs
- Paper Towels
- Running Water
- To prevent staining your hands with food coloring, put on disposable gloves.
- Squirt shaving cream into the container and smooth it out with a plastic spoon so that you have at least 1/2" of shaving cream standing in the container.
- Place drops of the food coloring that you like onto the shaving cream.
- Using a toothpick, swirl the colors around in the shaving cream to create a pattern that is pleasing to you.
- Place 1 side of the egg on the shaving cream, and allow the egg to sit in the colored shaving cream for 5 minutes.
- After 5 minutes, lift the egg and turn it so that an uncolored portion is toward the shaving cream.
- Place the uncolored egg portion down into an unused area of colored shaving cream.
- Repeat steps 6 and 7 until the egg is completely covered in colored shaving cream.
- Allow the egg to sit for 5 additional minutes.
- Use gloved hands to remove the egg from the colored shaving cream and rinse it under running water.
- Gently dry the colored egg with a paper towel.