Monday, June 15, 2009

Part 6- Application of Convection

The freezer compartment is usually found near the top part of the refrigerator as the cold air below the freezer compartment sinks. This sets up convection currents which cools all the food in the refrigerator effectively.

Air Conditioners
Air conditioners are usually placed high in the room because cold air blown sinks as it is more dense than the warm air in the room. The warm air displaced by the cold air, rises up and is drawn into the air conditioner until it is cooled. It is then blown out again, creating a cycle of convection current.

The Radiator: a cooling system in a car
When a car engine has been running for a long time, alot of thermal energy is produced. It is necessary to cool the engine before it becomes overheated. The engine is surrounded by water. When this water gets heated, it flows into the copper tubes which include cooling fins. A fan causes air to flow past these tubes to cool the water in them. The cooled water then flows down, back into the engine through a hose. A water pump is usually employed to facilitate the flow of convection currents back into the water surrounding the engine.

A hot water system
Operation for a hot water system is based on the principle of convection. Convection currents drive hot water from the top of the boiler into the hot water storage tank. Cold water from the storage tank is then drawn into the boiler until it becomes heated.

Land Breeze
At night, the sea temperature drops slowly as compared to the land which cools rapidly. The sea is now warmer than the land. The warm air rises above the sea and cool air above the land moves out to take its place and a land breeze is created.

Sea Breeze
During the day, the land heats up faster than the sea. Air above the land is heated. It expands and rises up. The cold air above the sea then moves inland to take its place, thus creating a sea breeze.

1 comment:

  1. it's so very nice example of convenction and i will finish my assignment in science thanks that the good example....