Friction is not always an advantage. It is a necessary evil. There are situations when we want to reduce friction. Let’s find out the methods of reducing friction with some examples.
Methods of reducing friction:
- Make surfaces smooth by grinding
- Lubrication
- Streamlined body
- Reduce pressure or weight on the object
- Reduce contact between surfaces by electrostatic magnetic levitation, etc
- Use rolling friction instead of sliding friction
- Use fluid friction instead of the dry friction
First, let us find out why we need to reduce friction.
Disadvantages of friction
- Unwanted heating effects, like forest fires
- Unwanted noise pollution, like highway road sounds
- Wear and tear are most commonly seen in shoes
- Reduced efficiency in machines
- Slows down many processes
Now, let us discuss the methods of reducing friction in detail with some examples. Friction depends on many factors. We have to optimize the factors for the respective application.
1. Make the sliding surfaces smoother
To reduce friction, we can make the sliding surfaces smooth. Friction occurs when two surfaces slide against each other, and the interlocking mechanism at a microscopic scale is the primary cause of friction. By reducing this interlocking, we can minimize the amount of friction between the surfaces.
Methods for making surfaces smooth:
- Grinding: A hard substance is used to grind and break the irregularity on the soft surface. Examples include polishing wooden surfaces, tiles, marbles, etc.
- Sandpaper: It is also a type of grinding, used for fine adjustments.
- Chemical etching: Harsh chemical treatments are done to reduce irregularities on surfaces.
Image by _Alicja_ from Pixabay
2. Application of lubricants:
Lubricants are substances applied onto surfaces to reduce friction. It can reduce heat generation and also ensure smooth sliding. Lubricants are mostly semi-solid paste-like materials that reduce dry sliding friction.
Examples of lubricants to reduce friction:
- Application of oils on door hinges for easy movement.
- Lubricants in car engine parts
- Application of grease in bicycle parts
- Paints for prevention of corrosion
3. The streamlined design of the sliding body:
A streamlined body helps in reducing friction, especially in fluids. It enables the sliding body to easily pass through the medium with the least resistance. The streamlined body of fish and birds is mimicked to ensure minimal friction.
Image by yukitohiraki from Pixabay
4. Reduce contact between surfaces:
Reducing contact during sliding can reduce friction. But, is it possible?
Yes, we can reduce contact by magnetic levitation or by charging both surfaces with the same polarity. Maglev (magnetic levitation) trains run on the principle of magnetic levitation to reduce friction in order to increase speed and travel experience.
5. Convert to rolling friction:
Sliding friction is always greater than rolling friction. Imagine a car with square wheels. Rolling friction is applied widely in our daily lives.
Examples in our daily lives: Ball bearings use balls to separate two bearing races. Hence sliding friction is converted into rolling friction. The races won’t slide over each other now but transfer the load to the balls through rolling friction.
6. Reduce pressure or weight on the object:
Friction is directly proportional to the normal force applied to it. Since we are on earth, the weight of the body is the normal force on the object generally. In space, there will be very less or no friction. So, choose materials wisely to reduce friction.
7. Use fluid friction instead of dry friction:
Fluids offer less friction compared to solid surfaces. That is why aircraft can travel at high speeds compared to cars. Also, when we are applying lubricants or oil onto surfaces, we are essentially converting dry friction into fluid friction.
There is one last method of reducing friction. This may not be practically possible, but in theory yes. If we remove the gravitation pull of the Earth then, the friction between cars and the road, our shoes and ground, etc would be removed. Or even if we reduce the gravitational pull, the friction decreases. This is just theory, won’t happen in reality!
