A
In this experiment, you'll see whether salt has any effect on the way water freezes.
You'll need
● Salt ● Cups ● Crayon
● Spoon ● Fridge
1 Put three spoons of salt in one cup and mark it "1". Put one spoon of salt in one cup and mark it "2". Mark the last cup "3" but don't put any salt in it.
2 Pour water in each cup almost to top; stir 1 and 2 until salt dissolves(溶解).
3 Put the cups in the fridge, and check them the next day.
What happens
No. 2 froze, but its ice was softer than No. 3.
No. 1 froze but not completely.
No. 3—the plain water froze and made the hardest, most solid(固体的) ice.
In No. 1, the water will be extremely salty and the ice will be much less salty because the water is too salty to freeze.
(
) 1. How many kinds of things are needed to do the experiment?
A. Two. B. Three. C. Four. D. Five.
(
) 2. What are the differences among the three cups?
A. Cup 1 has the most water in the beginning.
B. The ice in Cup 3 is softer than that in Cup 2.
C. There are different spoons of salt in each cup.
D. The cups are put into the fridge at different time.
(
) 3. What does this experiment show?
A. Salty water is easy to freeze.
B. Salt can be used to make ice.
C. Salt can help stop water freezing.
D. Salt makes no difference to the ice.
