When you were little, you probably read the Dr. Seuss book Green Eggs & Ham. Here’s a little pH trick to make some green eggs just like in the book.
What You Need:
- Frying pan and stove
- Red cabbage (it’s called red, but it looks purple!)
What You Do:
- Chop a 1/2 cup of cabbage, cover it with boiling water, and let it sit for 10 minutes until the water is dark purple. Strain out the cabbage.
- Crack an egg and separate the egg white from the yolk by carefully pouring the egg from one half of the shell to the other over a bowl. (Or you can pour the egg into a slotted spoon over a bowl instead.) Set the yolk aside.
- Mix a little cabbage juice in with the egg white. What happens?
- Grease the pan and let it heat up a little, then pour the egg white in.
- Set the yolk in the middle of the egg white and finish cooking!
Red cabbage contains pigments called anthocyanins, which change colors when they come in contact with acids (low pH) or bases (high pH), making them a natural pH indicator. When the cabbage juice comes in contact with an acid (like vinegar) it will turn red, but when it is mixed with a base it will turn bluish-green. What does this project tell us about egg whites, then? Egg whites are basic (also called alkaline) and so they turn the red cabbage juice green.
Make a regular egg float in a 250 ml beaker! Use a funnel to pour a layer of salt water underneath a layer of water. Do this by placing place the tip of the funnel at the base of the baker filled halfway with fresh water. Make sure its pointy side is up against the side of the beaker. Carefully add an egg and watch it float. Raw eggs float in salt water, but sink in fresh water.