How to open the lid of a thermos cup?

When you pour hot water into a cup, the air and water in the cup expand, but after a while, they both become cold and contract, which creates a great pressure difference between the inside and outside of the cup. Under this pressure, it is difficult to unscrew the lid of the cup.

The concrete solution to the problem that the lid of thermos cup can't be opened;

1, turn the cup upside down, tap the bottom of the cup several times, and then screw on the lid.

2. Twist hard. When the force we use is large enough (that is, when the friction between the force we use and the cup cover is greater than the pressure formed by the temperature difference), the cup cover is unscrewed.

3. Use a key (other metal pieces can also be inserted wider without damaging the lid) to gently pry open the gap between the lid and the mouth of the cup, and the air will hum in, and it will be easy to open with a slight twist.

4, can not open the cup is generally negative pressure, you can put the cup in hot water, when the water in the cup heats up, the volume expands, it is easy to open.

5. Freeze in the refrigerator first. After taking it out, pour hot water on the lid (just cover it) to ensure that it can be opened.

6. Quickly heat the cup cover to make a gap between it and the cup body.

7, can not open the cup is generally negative pressure, you can put the cup in hot water, when the water in the cup heats up, the volume expands, it is easy to open.