How convection takes place?

Answer 1

The Convection occur inside the mantle (earth)

Answer 2

A difference in temperature.

Higher temperatures cause higher pressures and lower density. Another region where the temperature and pressure are lower, and density higher will naturally go to the region with the higher temperature. It's a difference in gradients which causes this movement of a mass of air or any other fluid.

Answer 3

Particles are heated up and lose their density. Lighter/ less denser partcles move upwards and the heavier ones come down until they lose their density too. The same process goes on and on until the particles have all lost their density and heat is gained...

Answer 4

Water boiling in a pan.

The heat transferred through the bottom of the pan to the cooler waters at the bottom of the pan heat those waters, they now are less dense relative to the water at the top of the pan due to their higher heat, they rise to the surface, forcing the cooler water to the bottom.

Answer 5

In most fluids (either a liquid or a gas) if you increase the temperature it will make them expand, swell up, so that they become less dense. When they are less dense they float upwards more easily. If you cool them it makes them denser, so that they sink more easily. Whichever way they go, they take their extra heat, or lack of heat, with them. Heat can also travel by conduction, hotter atoms bumping into cooler atoms, which passes on their heat, but conduction is only fast over very small distances. Over long distances it is enormously slow. Convection can carry heat as fast as the fluid can move, which sometimes can be very fast. For instance, even our strongest winds, including tornadoes and hurricanes, are caused by convection in one way or another.

If convection is caused by a high temperature in a small spot, such as at the flame of a candle, then the hot gas can go straight up immediately, pushing cooler gas, such as air, aside, and the cool air flows down into the space left by the hot air that flowed up.

If convection is caused by a high temperature over a large area, such as when the sun has heated a black pavement, maybe kilometres across, then the hot air at the bottom cannot easily go up because the cool air above it is in the way and the cool air cannot go down because along any part it might follow, there will be hot air below. It is as though you had traffic trying to go two ways along a crowded road and they were not following separate lanes. You would simply get a huge traffic jam. Sooner or later, some little bits of air will float up a little or sink down a little, and as soon as some such movements starts the convection starts and it all goes faster and faster. The flowing up or flowing down may become very much like the water flowing down the drain of a bath, forming a whirlpool. That is how tornadoes start.

Even when we don't have such a traffic jam in the air, but there is a big mass of cold air next to a big mass of hot air, then the way convection works is that the cold air sinks down and flows sideways under the hot air. That flow is a cold wind of the kind we get at what people call a cold front. It also can be a very strong wind.

Answer 6

Convection takes place when cool air is warmed, which then rises. As the warm air becomes cool, it sinks. It is this cycle of warm and cool circulating air that transfer the heat (from a radiator, for instance) by convection, and warms a room.

Answer 7

Convection occurs when heat is transferred through the movement of a fluid, such as air or water. The fluid near a heat source becomes warmer, causing it to expand and become less dense, allowing it to rise. Cooler fluid then moves in to take its place, creating a continuous cycle of heat transfer.

Answer 8

only in liquids and gases, not solids as conduction takes place in solids.