Air conditioner and coolers

AC's and coolers are based on Newton’s law of cooling.

What happens when we place hot water in a bowl?

Initially the temperatures falls rapidly and then slowly. This is because of Newton’s law of Cooling. When the difference in temperature between the hot water and the environment is high, the exchange of heat between the environment and the hot water is fast. Its like the tendency of the hot water to co-operate with the environment. It also desires to come to the same state of the environment.

In Air conditioner, the heat inside the room in the form of hot air ( high temperature), is absorbed by a coolant ( low temperature ) and is exhausted to the outside atmosphere. Exchange of heat occurs between the room and the coolant. The coolant (liquid) changes its form to gas by absorbing heat and was expelled towards outlet. There it releases heat and becomes liquid again, which is again used for absorbing heat from the room. This takes place as a continuous process.

Coolant absorbs heat and evaporation occurs (Evaporator part in AC)

The hot gas expands and cools to liquid again due to exchange of heat from outside air (Condenser)

To use the same coolant again and again for air conditioning purpose , compressor is used in the system.

 

 

What is the difference in working between air conditioner and air cooler?

Instead of coolant, in air cooler, water is used. Have you heard that we have to replace water in air cooler often. There will be moist pads inside the cooler and simple air movement system is enough. Because of air rotation, hot air is absorbed by the cold air in the cooler, hot air is condensed by the moist pads and again flown as cool air in to the room.

Lighter

Gas lighter

 

It is based on law of conservation of energy. 

"Energy can be neither created nor destroyed. But only can be transformed from one form to another"

 

What do we do while lighting gas stove using lighter?

We press it with some energy, mechanical energy.

And what we are getting is electric spark, electrical energy. So in a gas lighter, mechanical energy is converted to an electrical energy. And now, next question. What’s inside the lighter which converts the energy?

It is a piezoelectric crystal, quartz. Piezo (mechanical)electric crystal acts as a transducer( a device which converts one form of energy in to another.

Cigarette lighter

Same principle as gas lighter. It is designed as one press, one spark.

But lighters working under piezoelectric principle do not work at great heights (above 800 feet’s). The higher the altitude, less likely the lighter to work.