You can tell if an egg is fresh by placing it in a deep bowl of water. If the eggs sinks, it's good; if it floats, it's bad. This happens because the egg absorbs air through the shell as it ages. As the membrane inside the egg shrinks, the air fills the pockets between the membrane and the shell, which causes the egg to float. Old eggs also have very runny whites and flat yokes which tend to break when the egg is cracked.
More Incredible Edible Egg Facts:
- Chicken egg colors can vary from white to light beige to dark brown — even to light blue or green, depending on the species of chicken.
- Chickens have been laying eggs for humans since ancient times. Evidence has been found that eggs were laid for man as far back as 1,400 B.C. in China and Egypt, and domesticated chickens laid eggs as far back as 600 B.C. in Europe.
- Egg size classifications are determined by weight. A jumbo egg typically weighs about 2.5 ounces (70 grams) or more, a large egg is 1.9 ounces (56 grams) and medium eggs are 1.7 ounces (49 grams).
- In the United States, there are about 280 million chickens producing the eggs for sale. Each chicken produces about 250 to 300 eggs per year. The chickens in the U.S. collectively lay about 75 billion eggs per year — 10% of the world's total egg production.