Neighbors roll and drop metal balls from above: why does this strange sound come about?

Not always people can correctly explain the cause of a phenomenon. The simplest explanation is often incorrect. So the sound of rolling metal balls overhead does not occur at all, as some people suggest.

Causes of the strange sound of metal balls

Over the years, people in various parts of the world have heard strange sounds from neighbors from above. This sound is similar to rolling metal balls and it is heard only at night. Due to the mass character of this phenomenon, people began to make very different, sometimes ridiculous, assumptions. Here are just a few of them:

• sounds of falling objects or bottles - a bottle can really roll, making a similar sound. But you will not hear him a floor below. A thick slab between floors and flooring will damp out most of these sounds;
• the elevator that goes back and forth - the rhythmic sound of the elevator can really be confused with many phenomena. But all the witnesses noted the sound of “balls” as very loud. An elevator can make so much noise only in the event of a serious malfunction. And besides, the sound was seen in houses where there were never elevators;
• opening doors at the sliding wardrobe - the doors on the wheels in the wardrobes really make sounds when opened. But they are not so loud, and why would anyone constantly open the closet at night? Such an explanation does not hold water;
• sewer sounds - pipes can really hum, vibrate and make different sounds. But the sound of balls rolling on the floor is still not peculiar to them;
• children or animals play with round objects - a child playing with a ball is suitable, only at first glance. The sounds are too loud, and clearly of a metallic origin. And again - children do not play at night.
  

  The sound from a regular ball will be much quieter than that heard at night

Among all these false theories, there are only grains of truth. However, the answer, which is considered to be correct, is also only an assumption, just the least controversial. It is believed that the sounds of rolling balls occur under the following circumstances:

1. During the day, the building heats up, due to which its structure is expanding slightly (within the permissible norm). Deformation from heat is provided in the construction plan of any structure.
2. With this expansion, the pressure on the valves changes, due to which they are slightly compressed.
3. At night, the building begins to cool, and the load on the fittings decreases. An oscillatory return of the reinforcement to its original form begins, during which a rhythmic metallic sound appears. It is this sound that people mistaken for rolling balls.
   

   The sound is heard in panel houses because of the specifics of the design

Many things speak in favor of this theory - the reinforced concrete itself, which is used in construction, conducts sound perfectly. And the voids between the plates of the houses create a resonance, which this sound enhances.

In wooden houses, strange sounds are not uncommon for the same reason. When cooled after the heat, the tree may creak, “moan” and even hum.

Video: explanation of the sound of rolling balls

There are many jokes and misconceptions about the origin of a mysterious sound. There is only one logical explanation for him, although people do not stop building theories. And now you know what to assume when you hear a strange sound above your head.