A metal entrance door swings freely in the winter, but when

the weather turns warm, the door sticks and seems too big

for the doorframe. Using your knowledge of particle theory,

explain what is happening.

This phenomenon occurs because the door, being metal and leading to changes in temperature, undergoes proportional and morphological changes, metals face expansion and expansion in the presence of heat, called thermal expansion.

On the other hand, against the cold, thermal contraction is suffered, that is why its volume decreases, and it contracts.

Explanation:

The expansion phenomenon of the door is not linear, since it increases its volume in width and height, therefore simultaneously on the entire surface.

When an area or surface expands, it does so by increasing its dimensions in the same proportion. For example, a metal sheet increases its length and width, which means an increase in area. Area dilation differs from linear dilation in that it involves an increase in area.

The area expansion coefficient is the increase in area that a body of a certain substance experiences, with an area equal to unity, as its temperature rises one degree centigrade. This coefficient is represented by the Greek letter gamma.

Regarding shrinkage, a clear example of this is when a metal foundry or a weld shrinks, sometimes it is difficult to understand with examples like these (doors) because it is little noticeable by our eyes and the dimensional changes for our perspective. it is infima.