One is because the density of the egg is less than the density of the salt water. Two, the egg has air chambers that increase the buoyancy of the egg.

Eggs have a hard shell on the outside and air chambers, albumen and yolk parts on the inside. Rich in cholesterol, nutritious, an egg weighs about 50 grams, containing 6-7 grams of protein, 5-6 grams of fat. Egg protein amino acid ratio is very suitable for human physiological needs, easy for the body to absorb, the utilization rate of up to 98% or more, high nutritional value, is one of the food often consumed by humans.

Expanded:

Odd Customs

1. In the United Kingdom, every holiday feast, people love to break the egg, drop into the water, to its shape to account for the future life is beautiful. Then, it is mixed with sugar and steamed, which means that life is full and harmonious.

2, France

In some remote villages in France, men and women get married, the bride always like to steal the eggs in the pants. When stepping into the bridal chamber, deliberately fall, let the eggs fall out, to show that they will "lay eggs".

3, Yugoslavia

Young people in Yugoslavia, the egg as a sacred, pure symbol of love. Every Easter on the first Monday, young people gather to dance, talk about love, in love with young men and women, always like to be faithful. If the man does not eat the eggs sent by the woman, it means that do not love each other, or love breaks down.

Baidu Encyclopedia - Eggs