Convection: Land Breeze, Sea Breeze

Land Breeze













In the night, the temperature of the ocean is warmer than the land. The warm air then rises to form clouds. The cool air above the land will sink and rushes towards to ocean the fill the space there, thus we get our land breeze.













In the day, it is the exact opposite of the night. Instead of the ocean being warmer than the land, the air above the land is now warmer than the air above the ocean as the sun is out and the ocean is a poorer conductor of heat. The warm air above the land rises up to form clouds while the cool air above the ocean sinks. The cool air then rush towards the land, thus we get our sea breeze.

Convection: Convection in Air

He places a joss sticks into the first hole. The smoke of the joss sticks then went towards the direction of the candle flame. As the smoke from the joss sticks are hot air, they are already expanded and rises up. As they are in the box, they rises up and reaches the top of the box. When hot air touches the top, they are being pushed to the side by the recently warmed air, which is the candle flame in this case.

Convection in Radiators
Radiators heats up the room by giving off heat by radiation and convection. The radiator warms the air that is around it and the warm air rises, which will pull the colder air towards the radiator, and the radiator will heat the air and the cycle restarts again.

The reason why radiators are usually placed on the floor is because hot air rises, cold air sinks.

Convection: In Liquid

The video shows how convection is like in liquid.

http://euiveoivoaviik.43.gs/mod_tech/node76.html















As water is being heated, the hot water rises while the cool water falls. This is because the cool water are denser than the hot water.
*The heat element is at the bottom.
















This shows the convection current in the liquid when the liquid is being heated.
The hot liquid is represented by the red arrows, which is going upwards.. The liquid that is colder is represented by purple arrows, which is going downwards.

Another Example of Convection: Lava Lamp


The lava lamp heats the wax, which will cause the wax expand and become less dense. As it is less dense, it rise upwards. As the wax cools and becomes denser, it will drop to the bottom again and gets heated again, and the whole cycle repeats.

Another Way of Convection: Ice Cube Convection


The green star-shaped ice cube was put into the warm water. The ice slowly melts and the water sinks down as it is colder and denser than the warm water. The warm water then rise up.

Convection

Convection is the main mode of heat transfer in liquids and gases.
It is the process by which heat is transmitted from one place to another by the movement of heated particles of gas or liquid.

Convection only takes place in gases and liquids, but not in solids as the particles cannot move far away from their places in solids. It is the particles in hot liquid or gas that transmit the heat energy. It involves the movement of the hotter fluids form the hot region to the cool region.

How Convection Work
When liquid is being heated, the layer of water that is closer to the heat source will expand and become less dense as compared to the layer of water above. Expanded water will then rise while the layer of water that is not expanded will sink. This is then called the convection current.