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This week's LabZone activity
Sept. 6, 2006
Secret Boiled Egg Message
Some
agents during World War II hid secret messages in boiled eggs! In this
project you'll do this using two items that are available in your
grocery store's spice aisle: alum and vinegar. As you write on the egg
shell with this mixture, you leave behind messages that can only be
seen once you remove the shell! How is this possible? Well, the vinegar
dissolves the calcium carbonate in the eggshell, allowing the alum to
pass through the shell and discolor the egg white.
Supplies
- 12 hardboiled eggs
- 1/4 teaspoon salt
- 2 tablespoons white vinegar
- 2 tablespoons alum
- Q-tips
- With an adult's help, hard boil a dozen eggs. Place the eggs in the
water and bring water to a boil. Set your timer so that the eggs simmer
for 12 minutes. Here's a tip: Add some salt to the water, as it helps
make the eggs peel easier.
- Have your mom or dad drain the hot water and
rinse the eggs in cold water. Place them in a bowl or back in their
carton, and put them in the refrigerator to cool.
- In a small bowl, mix the white vinegar and alum together to form a paste.
- Hold an egg in one hand by your thumb and
forefinger while you write a message. Use the Q-tip like a pencil,
dipping it into the paste.
- Store the egg in the refrigerator overnight
so the message will have time to seep through the shell and set. Peel
the shell off the egg to read your secret message! You'll notice that
some eggs are finicky, so this trick doesn't always work. Try a few and
some will be successful!
Reprinted with permission from Great World War II Projects You Can Build Yourself by Sheri Bell-Rehwoldt. Published by Nomad Press (www.nomadpress.net), distributed by Independent Publishers Group (www.ipgbook.com). Copyright © 2006 by Nomad Press.
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