Compare the bottom edge of your digging shovel to the top edge (if you don’t have a shovel at home, find a picture of it online). What differences have you noticed? What are they caused by?
The lower and upper edges of the shovel differ in area. At the upper edge, it is larger in order to reduce the pressure of the shovel on a person’s shoes when acting on the shovel with a foot. On the contrary, the lower edge is made sharp so that the pressure of the shovel on the ground is maximum.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.