in a lava lamp lava moves up then fall back down due to heat causing density change. what is this cycle called

Question

the same thing applies for earths mantle. the same thing is happening there. warm lava near the bottom is rising up because when heated density is lower and when lava is at the top it is cooler so it is more dense and falls back down. what i need to know is the name applied for this kind of cycle of change.

and if you can, can you tell me how earths mantle is different from a lava lamp???

Answer 1

It's called convection.

The differences between the mantle and a lava lamp have primarily to do with scale. The heat, the distances, the pressure and the time are all much larger in the mantle. Also, in a lava lamp, the "lava" is different stuff than the liquid it rises and falls through. In the mantle, it's all the same stuff.

Answer 2

Convection

Wax at the bottom heats until it melts, and eventually becomes less dense than the liquid above it. At this time, a portion of the wax rises towards the top of the container. Near the top, away from the heat source, the wax cools, contracts, and as its density increases it begins to fall through the liquid towards the bottom of the container again. Part of the reason for the shape of the lava lamp is that at the narrow tapered end there is more surface area per unit volume of liquid, therefore making liquid in this area experience a higher rate of cooling than that at the bottom, even if the lamp itself were off. This is a macroscopic, visible, form of convection heat transfer, although it also occurs on a molecular scale within the liquid itself. The difference in temperature between the top and bottom of the globe is only a few degrees.

One mass of wax may rise as another falls. The metal coil at the bottom helps to overcome the surface tension of the individual wax droplets, causing the descending blobs to coalesce into a single molten wax mass at the bottom of the container. The cycle of rising and falling wax droplets continues so long as the bottom of the container remains warm and the top of the container remains cool. Operating temperatures of lava lamps vary, but are normally around 60 °C (140 °F). If too low or too high a wattage bulb is used in the base, the "lava" ceases to circulate, either remaining quiescent at the bottom (too cold) or all rising to the top (too hot).

Chaotic behavior makes the movement of the wax unpredictable. The Lavarand system used this unpredictability as the basis of a hardware random number generator.

Answer 3

Lava Lamp Top

Answer 4

um i forgot what it was called .**** what was it.

convection currents yea.


earth is different because well not really,
uh the earths plates float on the mantle.

Answer 5

convection.

The mantle is different because it is a solid (rock) - a very, very thick (viscous) solid that still moves.