April 2017

Egg-cellent Science Egg-speriments (4/5/17)

Bouncy Eggs

Glowing Egg

MATERIALS:

  • Uncooked Eggs
  • Plastic food storage container with lid (or a clear bowl and cellophane wrap)
  • Distilled White Vinegar
  • Large Spoon
  • A refrigerator
  • Paper Towels
  • Water

INSTRUCTIONS:

  1. Carefully place the Uncooked Eggs into a clean food storage container. For best results, the eggs should have a bit of space left in between them. And they definitely should not be stacked on top of each other!
  2. Add enough Distilled White Vinegar to completely cover the eggs in the container. Do you notice any immediate changes?
  3. Tightly seal the container with a lid, or a piece of cellophane wrap.
  4. Place the container inside of the refrigerator. After an hour, check the container for any observable changes.
  5. Refrigerate the eggs for a full 24 hours.
  6. The next day, remove the container from the refrigerator. Gently lift each egg from the vinegar bath using a large spoon. Rinse the eggs under running water while gently wiping them with a paper towel. Have the eggs changed at all? Why?
  7. Discard the used vinegar from the container. Place the rubbery eggs back into the container.
  8. Repeat steps 2 through 7 twice more.
  9. After the third full day of soaking in vinegar, your Bouncy Eggs are finally ready! They will be very rubbery and bouncy, they will be slightly translucent, and they will be Egg-stremely fun to play with. But remember to be gentle with them! You definitely DON’T want to scramble these vinegary eggs!

HOW DOES IT WORK:

The hard outer layer of a chicken egg’s shell is made primarily from a substance called Calcium Carbonate. This chemical compound is also the main component of oyster pearls, seashells, and even limestone rock! Calcium Carbonate is an alkaline substance that will react with acids to produce Carbon Dioxide gas bubbles (it is similar to the well-known Volcano Experiment that mixes Baking Soda and Vinegar).

Over time, the Acetic Acid in the Vinegar completely reacts with the Calcium Carbonate in the egg shell to dissolve the egg’s hard outer shell and reveal the elastic membrane underneath. This protective double-layer of strong and stretchy proteins is able to wiggle, bend, and even bounce while containing all of the egg’s insides together!

THE MORE YOU KNOW:

Look closely at the surface of a normal chicken egg. Now look closer using a magnifying glass! Do you see tiny dots or holes on the surface? These holes are called pores. They allow air to flow through the eggshell. Oxygen enters the egg to ventilate the developing baby chick, while harmful carbon dioxide can also escape from the egg.

GOING ONE STEP FURTHER:

  1. After making your Bouncy Eggs, grab a flashlight and hold it beneath a Bouncy Egg. Through the egg, you can see that light is actually able to pass through this semi-transparent (or translucent) egg. Amazingly, if you move the light around, you might notice a round shadow being cast inside of the egg. What do you think could be causing this shadow inside of the egg?
  2. Challenge your friends to a Bouncy Egg Drop Challenge! On a well-covered, flat surface (or even better, on a flat surface outside) take turns dropping your luckiest Bouncy Eggs from a few inches high. If they survive, try dropping them again from a couple of inches higher, then higher. Whose egg can survive the most drops? From how high can you drop a Bouncy Egg before it bursts? Be sure to clean up your mess afterwards.

Boiled and Bottled Eggs (4/5/17)

Bottled Egg

MATERIALS:

  • Hardboiled Eggs (ask a grown up to help you hard boil a few eggs, or purchase them pre-cooked and shelled at a supermarket)
  • Glass Bottle with an opening that is slightly narrower than the size of your peeled eggs (we used a Starbucks Frappuchino® glass, but a glass milk bottle or a laboratory Erlenmeyer flask would also work as well).
  • Funnel
  • Boiling Water
  • Adult Assistance

INSTRUCTIONS:

  1. Ask your adult assistant to help you hard boil a few eggs. Any recipe should work, but be sure that the eggs are hardboiled.
  2. Carefully peel the shell from a few of your eggs and rinse the eggs under fresh water.
  3. Now ask your adult assistant to bring a glass of water to a rolling boil. They can either heat the water on a stove top, or microwave it in a microwave-safe container for a couple of minute.
  4. Place the glass bottle on a flat surface, ideally a surface covered in paper towels to protect it.
  5. Using a heat-resistant funnel, carefully fill the glass bottle ½ full of boiling water. Let it sit, undisturbed for about 30 seconds.
  6. Gently set your shelled hardboiled egg onto the opening of your glass bottle.
  7. Now just wait.
  8. Wait.
  9. Wait some more.
  10. What happened to the egg?!?

HOW DOES IT WORK?:

First, we should look at the awesome science of simply boiling an egg!: Eggs are a great source of protein (the egg whites are about 12% proteins, and the yolk can be over 17% proteins!) These proteins are made from long, twisted molecules called amino acids. The shape of the amino acids determines the properties and characteristics of the proteins that they make up. But we can change the protein’s characteristics by reshaping—or denaturing—their amino acids. Proteins can be denatured by adding certain chemicals or by changing their temperatures. When we add the eggs to the hot water, the amino acids in the egg curl up and cause the egg white and yolk to solidify!

Now let’s explain the Boiled and Bottled Egg experiment itself: As you likely know already, air takes up space because it is made of gas molecules. When we pour the boiling water into the bottle, these gas molecules also begin to warm up and expand to take up more room. When we place the egg on top of the bottle, the warm air becomes trapped inside of the bottle, separated from the cooler air outside of the bottle. After a few minutes, the air (as well as the once-boiling water) in the bottle will start to cool down. The air will shrink back in volume and create an air vacuum that literally sucks the egg into the bottle!

THE MORE YOU KNOW:

There are several other ways to denature the proteins found in egg whites. One common way, often used in the kitchen, is to beat the egg whites with a whisk. As the egg whites are vigorously whisked, the amino acids are literally pulled into a new shape! These newly-shaped amino acids also trap air into tiny pockets that puff up the white into a fluffy foam…perfect to top a lemon meringue pie!

GOING ONE STEP FURTHER:

  1. Get an adult assistant to perform a these fiery variations of the Boiled and Bottled activity!
    1. Fold a piece of printer paper into a long, thin rectangle. With a candle or a lighter, set fire to one end of the paper rectangle while holding the paper on the far end. Quickly drop the burning piece of paper into the bottle and set the hardboiled egg over the bottle’s top. As before, the egg will get sucked into the bottle! But what is different in this experiment?
    2. Take three birthday candles and insert them into the pointed top of a hardboiled egg (be sure that the candles are placed very closely together). Light all three of the birthday candles at once. Turn the glass bottle upside down and lower the bottle over the lit candles and egg. If the candles blow out too soon, try it again until the egg is pulled upward into the bottle! (In each of these experiments, the fire source consumes oxygen in the air inside of the bottle. This causes the air vacuum that ultimately sucks the egg into the bottle.

Not that is some EGG-ceptional Science!!!