Introduction on ways to decrease friction
Friction is a necessary evil. In some situations, it plays a positive role whereas in others, it is not needed. The net efficiency of any machine depends on the amount of friction present in that machine, because a large part of the input energy of all machines is wasted in overcoming friction between its various parts, and thus the total output from the machine decreases.
There is thus a need to find ways to decrease friction in order to make machines more efficient and to increase their life time. These ways of decreasing friction can be applied in different parts of machines according to the function of that part, and thus a more efficient machine is constructed.
Ways to decrease friction
The following techniques are different ways to decrease friction used widely:
Use of lubricants
The use of lubricants like oil and grease helps to reduce friction by forming a thin film between different parts of a machine. This film covers up the scratches and lumps present on the surfaces of different parts and thus makes the surface more even than before. This reduces interlocking between the two surfaces, and hence the parts of the machine run smoothly.
Use of ball bearings
Two moving surfaces in a machine are fixed by placing small balls or rollers made out of steel in between them. This way, the moving parts avoid direct contact and sliding friction is changed to rolling friction. Rolling friction is less than sliding friction, thereby decreasing the amount of friction in the machine.
Other ways to decrease friction
The unevenness of surfaces can be reduced by polishing them. This will reduce the interlocking between surfaces in contact thus reducing friction.
Using soft, fine powder
Soft, fine powder like talcum powder and graphite powder also helps in filling in the microscopic scratches and grooves on a surface and thus make it more even and less prone to interlocking with other surfaces. Thus, friction is reduced.
Streamlining is the process of making a machine’s shape such, that avoids resistance from air and water molecules while moving. For example airplanes have a streamlined shape which reduces friction between air molecules while flying. This is because fluids move with less friction over a streamlined surface, and the object moves forward as if cutting through them. The following diagram shows a streamlined and a blunt body:-