Although the fan rotates, why does it become dirty?

 Courtesy- Ahanaf Ahmed, Batch-201, Department of EEE, Green university of Bangladesh

The world is scientific and there is no doubt that everything in the modern world depends on science. From waking up to falling asleep again at night, all the work we do in our daily lives is obsessed with science.

Among all the science that is applied in our day-to-day life, one idea might catch the attention of many people.

By dint of modern science, we all use fans to cool ourselves down. It seems to me that except for some people everyone uses a fan and they usually face a problem.

Basically, we saw that when our fan rotating then some dust usually attaches surround to the fan body, and these can't fall after switching off the fan.

But why does this happen?

Before I start, would like to disclose a common example,

As kids, we were familiar with the paper-comb experiment where we would put little pieces of paper in our hair and after combing, we realized that the comb collected the pieces of paper. With this observation, we concluded that this was due to static electricity where the comb is charged by friction and the paper is attracted to the comb. 

Seeing how there is friction between the comb and the paper, what can we observe about the relationship between static electricity and a fan's dust attachment?

 Dust is something that is always around us. They are made up of particles of solid matter and are microscopic even though we can see larger particles with the naked eye.

We sometimes see dust particles flying around in our house and accumulating on different surfaces. These particles of dust are produced by humans as our skin sheds very tiny particles. They can also be produced by the fibers of our furniture, carpets, clothes, and from the outdoors.

As they usually fly in the air, these dust particles become charged which can be both positive and negative.

When we switch the fan on and it rotates, there is continuous friction that is created between the air and the fan's blade which produces static electricity.

And the charged dust feels an attraction with the charged blade attracted and similarly to magnets, opposite charges attract, the fan attracts all the dust as it’s rotating.

The quantity of dust accumulation varies from place to place. For example, in Dhaka, due to the type of environment, there is so much dust in the air with 7.1 micrograms per cubic meter while in the villages the dust accumulation is significantly less than how much is produced in the city. This allows for fans to collect less dirt in the villages than in the city as well. Thus, with a rotating fan that faces much more friction with the dust there is static electricity constantly being produced.

Usually, these dust deposits in the fan prevent the fan from rotating, so the fan cannot properly provide cooling.

However, there are some ways to prevent so much dust accumulation. 

One significant way is that we can use dust repelling spray which is available in hardware shops or any other store. After spraying this on the fan and wiping it with a cloth we can see a difference in how much dust is collected.

Another way is to use a slippery polish which does not allow too much dust to remain fixed on the fan.

 It is important to understand how small things can affect daily living such as dust in our environment. We should be concerned about how we take care of our environment and maximize ways to simplify our lives and live healthier. With these observations, we can see how static electricity changes things for us.