Warm tips
Question: Why can it be held firmly on the top of the cup or on the smooth wall/desk, but cannot be held on the sink or floor drain?
Answer: Actually this is an interesting physical phenomenon, because when it is placed on the cup or on the wall/ground, the air inside the floor drain cover is discharged. At this moment, the internal pressure is lower than the outside, so it can be absorbed.
(The inlet of the injection pool and the floor drain are ventilated, so this phenomenon cannot be produced.)
The main function of the floor drain cover is to cover it to effectively prevent odors and mosquitoes from overflowing.
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