What is the purpose of the hole on the chair?
When stacking these plastic chairs on top of each other, without this small hole, you would encounter a lot of difficulties in storing and transporting them.
If you remember the Magdeburg hemispheres physics experiment you learned in high school, you would know that the vacuum inside makes it very difficult to pull the hemispheres apart.
While the space between the two chairs is not a vacuum, if there is no hole, there will still be a similar effect, causing them to stick together, and we would need a lot of force to pull them apart.
In addition, when stacking the chairs on top of each other, if there is this hole, we can stack them neatly and firmly.
So, to some extent, we understand the purpose of this small hole, but the question is why does it have to be a hole that is neither too big nor too small, and why does it have to be circular and not square or triangular?
If a square or triangular hole is made, it would not be good, because these shapes often have sharp corners, so most of the pressure will be concentrated at the corners, and when someone sits on the chair, it will be easy to break.
Also, oval or other shapes with rounded corners are not used because a circle is the easiest shape to make a mold, so a circular hole is chosen for plastic chairs.
But why only one hole and not two or more? Because if it is only for ventilation, then one hole is enough.
Why is the hole not too big or too small? If the hole is too big, it will affect the structural integrity, while if it is too small, users will have difficulty gripping the chair when inserting their fingers.
In addition, there are many other scientific and interesting explanations for this small hole. According to the principle of expansion when heated and contraction when cooled, the more plastic used, the larger the volume change, so there needs to be an empty hole to reduce the amount of plastic used. Besides, creating such a hole makes it easier to remove the chair from the mold.
Another explanation is that when stacking chairs and threading something through the hole, the stack of chairs can be moved gently. Or it is believed that if the chair gets wet, this hole will help it dry quickly and avoid water retention.
Other functions of the hole on the chair
Ventilation
Whether sitting on a sofa or a long chair, sitting for a long time can make people feel uncomfortable, especially in hot weather, the buttocks will feel sticky. The small round hole in the middle of the chair provides ventilation, so people sitting for a long time will not feel uncomfortable.
Posture adjustment
When doing homework at home, children may sit unsteadily if not reminded. In fact, we can use the hole in the middle of the chair, we just need to prepare a stick. Insert the stick into the child’s clothes, then insert it into the hole in the middle of the chair to fix it, so that the child will no longer have a hunched back while sitting, no matter how long the child studies, the back will not hunch anymore, the belt will not squeeze anymore, no longer bent.