Silent late at night, sounds always come from the rooftop without anyone. What's going on?
When I was a child, I often heard various strange sounds upstairs. Originally, the answer was here:
Have you ever heard the sound of glass beads falling from the ceiling in the quiet of the night? And that night, there might not be anyone upstairs! Does this sound like a scene from a horror movie, but 80% of people have heard this kind of sound. Most people may think that someone upstairs has dropped something, or that a child is playing with glass beads. But in fact, the truth is not like this. So far, there is a saying that it's haunted!
That was lying to you!
In fact, the sound of marbles upstairs is caused by the slight movement of steel bars in cement pipes on the ceiling, and this sound is also closely related to a special type of mold.
We all know that most buildings nowadays are made of reinforced cement, while the ceiling is supported by two layers of relatively thin prestressed steel bars as a whole frame, which are then poured with concrete.
During the cement pouring process, due to factors such as the weight and flow of the cement slurry, the prestressed steel bars in the ceiling are subjected to stress in different directions. These stresses will gradually accumulate. After the house is built, due to slight movement of the foundation or other original factors, these accumulated stresses will cause small gaps and pores in the contact surface between the steel bars and cement.
When building electrical wires or pipelines, it is generally chosen to be installed inside the ceiling, and the outlet is usually located below the ceiling. Then, a mold that corrodes industrial materials and cement will slowly invade the fine joints between the steel and cement structures along these openings. A large amount of mold will accumulate on these contact surfaces, and the mycelium of the mold will gradually corrode the cement and other materials in all directions, forming hollow gaps. At this time, a certain steel bar may start to loosen and deform at these hollow positions.
Then, a sound similar to the sound of glass beads falling was produced.
