Question

We can use milk to make all kinds of things. Here’s how to make plastic:

You will need	Teaspoon Vinegar（醋） Measuring cup Whole vitamin D milk (nonfat or low-fat) Sauce pan Adult helper Stove
Do this	1. Pour 2 cups (500 ml) of milk into the sauce pan. 2. Ask the adult to heat the pan slowly on the stove. 3. Just before the milk boils, bubbles will start to appear on its surface. 4. When that happens, slowly put in two teaspoons of vinegar. 5. Keep stirring(攪拌) until the milk becomes rubbery(橡膠狀) and hard to move. 6. Remove the pan from the heat and let it cool. 7. When the milk is completely cool, remove the solid from the pan, squeeze it into a ball and wash it under cool running water.
What happened?	A chemical reaction takes place between a chemical(化學物質) in the warm milk and acid(酸) in the vinegar, and the result is a rubbery solid that does not dissolve in water. The milk has to be heated for this experiment to work. The white glue that comes in a squeeze bottle is one of the many useful things. That can be made from the chemicals in milk.

1.What do we need to make plastic?

A.Two cups of low-fat milk. B.An adult helper.

C.Vinegar, sugar and acid. D.The white glue.

2.Which of the following is true about the experiment?

A.The milk should be cool for doing the experiment.

B.Keep stirring the mixture of milk and water until it is cool.

C.Bubble will start to appear when the milk becomes rubbery.

D.A chemical reaction takes between the warm and the vinegar.

3.Which of the following is the best title for the passage?

A.Different Uses of Milk B.Glue Made from Milk

C.Different Uses of Plastic D.Plastic Made from Milk

Answer 1