I often hear the sound of marbles falling and rolling upstairs at night. What is this phenomenon?

I believe many people have heard the sound of marbles falling upstairs. Because someone is playing marbles upstairs. It is normal for marbles to bounce back when they fall to the ground. Sometimes, I will listen to the crash of the wine bottle on the ground, and sometimes there will be footsteps. This is all caused by people walking upstairs, just like I often accidentally knock over the bottle under the table, and sometimes it is normal for me to touch the spoon. Now high-rise buildings are basically secondary water supply, so there will be a water tank on the roof, and some developers will have this sound at the connection position between the water tank and the floor without damping; There is also a saying that the steel bars of stairs expand when heated and contract when cooled, and so is the lightning protection system of buildings. Anyway, it's normal to sweep the children and play. If it is serious, I suggest looking for the Ministry of Housing and Urban-Rural Development to check.

This is not a supernatural phenomenon. Don't panic. The sound of marbles upstairs is not transmitting death. Some people say that the sound of marbles on the floor is transmitting death, and human beings tend to be supernatural about this unexplained phenomenon. I don't agree with this statement.

The cement board is supported by fine steel wire mesh. During grouting, the impact force bends these steel bars, that is, they are elongated like bowstrings, and cannot be restored because they are surrounded by cement. It has always been like this. People are hopping upstairs, the floor is under pressure, and the sound of steel bars tightening falls like marbles.

There is also a mold that can corrode industrial materials and cement in cement buildings. It has long liked to live in such a porous environment as cement board, and can feed on minerals in cement. The center of contact between the fine steel bars in the cement slab and the cement is the favorite gap of these molds, where they grow and are not corroded from time to time. When these molds accumulate in the sun and the moon, the cement around the thin steel bars will be corroded, and the bent steel bars will bounce back because there is no constraint, bouncing back and forth in the center of the hole, just like the sound of marbles falling to the ground.