Question

Give Reason: The mosaic floors are laid in small blocks with glass strips in between them.

Answer 1

Hint: We all know that when we increase the temperature of any object mostly when the item is a conductor, the shape, size and volume of the object changer due to thermal expansion.


Completer step by step solution
When the object expands under heating, it changes its own shape. Maybe its length or breadth gets changed, and this all happens due to thermal strain that starts developing inside the object. However, if the item expands and there is no restriction in extending an object’s structure, then no thermal stress develops. Thermal stress may be tensile or compressive. When an object is restricted from expanding then the nature of thermal stress is compressive, but when an item starts contracting due to decrease in temperature, then the nature of thermal stress is tensile.
In case of these floors of mosaic, if the gaps are not left in between them, then the whole material will expand and may get cracked as the entire floor is restricted at the outer periphery. So small gaps are provided in between to give some area for thermal expansion.


Note: The amount by which a material expands or contracts for a single degree rise in temperature is called the coefficient of thermal expansion which is denoted as $\alpha $ . For the materials which are having a high value of $\alpha $ are expanding more for a single degree rise in temperature and the same case happens for the coefficient of thermal contraction, which is represented by ${\alpha _C}$