宋欣

An egg sinks to the bottom if you drop it into a glass of ordinary drinking water but what happens if you add salt？ The results are very interesting and can teach you some fun facts about density （密度）.

What youll need：

*One egg

*Water

*Salt

*A tall drinking glass

Instructions：

Pour water into the glass until it is about half full.

Mix in lots of salt （about 6 tablespoons）.

Carefully pour in plain water until the glass is nearly full （be careful to not mix the salty water with the plain water）.

Gently lower the egg into the water and watch what happens.

Whats happening？

Salt water is denser than ordinary tap water， the denser the liquid the easier it is for an object to float in it. When you lower the egg into the liquid it drops through the normal tap water until it reaches the salty water， at this point the water is dense enough for the egg to float. If you were careful when you added the tap water to the salt water， they will not have mixed， enabling the egg to amazingly float in the middle of the glass.

阅读选择：

1. What will happen if you drop an egg into a glass of ordinary drinking water？

A. It will float in the water.

B. It will sink to the bottom.

C. The result is not known.

2. How many things do you need to do the experiment？

A. Four. B. Three.

C. Two.

3. What is first put into the glass？

A. Salt. B. Water.

C.It doesnt say.

4. Why can the egg float in the water？ Because________.

A.the more the liquid is the easier it is for an object to float in it

B. salt water is thinner than ordinary tap water

C. the denser the liquid is the easier it is for an object to float in it