Explore the properties of water
How do you think you can fish an ice cube using a pinch of salt and a string? Through this simple experiment you will explore how water freezes and melts.
For this experiment you will need the following materials:
✔ Glass of water
✔ Ice cubes
Put several ice cubes in a glass of water. Take the rope and drop one end onto the ice cubes. While the rope is on the ice, sprinkle a pinch of salt on them. Wait two to three minutes and try to lift the rope. Don’t forget to record your observations about this experiment.
When you put the ice cube in the glass of water, two processes began to occur: the ice began to melt and the water began to freeze. Because the two processes happened at the same time, we can say that the ice and water are in dynamic equilibrium. Here, the rate of freezing and melting is the same. When the ice melts, the ice molecules begin to escape into the water. On the other hand, when water freezes, its molecules are captured on the surface of the ice. When this takes place at the same time, it can be said that no changes are created in the ice or in the water. This equilibrium state will hold as long as the water maintains its temperature at 0°C (32°F).
When you sprinkled salt on the ice cube, the equilibrium state was broken. At this time, melting is much faster than freezing, which caused the water to melt. However, in order to restore the balance, the freezing point of the water drops, causing the ice to freeze in the salt water. The salt begins to crystallize and the ice refreezes around the rope. This causes the ice cube to stick to the ends of the rope, allowing you to lift it simply by pulling on it!