Why put a coin in the refrigerator when you are away from home?

Put a coin in the refrigerator when you are away from home to judge whether the refrigerator at home continues to operate normally. If we catch the power failure, the food in the refrigerator may go bad. The specific method is:

1. First, fill a glass of water with transparent containers such as plastic cups and glasses, and put it in the freezer to freeze into ice cubes.

Put a coin on the ice, and then put the coin and the frozen cup in the refrigerator.

3. Go home and take out the glass. If the coin is still above the ice surface of the water cup, the refrigerator is operating normally. If the coin has sunk into the bottom of the cup or under the ice, it means that the refrigerator has been cut off and some food may have gone bad.