What is forced convection how does it differ from natural convection?
In natural convection, any fluid motion is caused by natural means such as the buoyancy effect, i.e. the rise of warmer fluid and fall the cooler fluid. Whereas in forced convection, the fluid is forced to flow over a surface or in a tube by external means such as a pump or fan.
What does forced convection mean?
Forced convection is a mechanism or a type of transport in which fluid motion is generated by an external source (such as a pump, fan, suction device, etc.
What is convection short answer?
1 : the action or process of conveying. 2a : movement in a gas or liquid in which the warmer parts move up and the cooler parts move down convection currents. b : the transfer of heat by convection foods cooked by convection — compare conduction, radiation.
What natural systems have convection cells?
Convection cells can form in any fluid, including the Earth’s atmosphere (where they are called Hadley cells), boiling water, soup (where the cells can be identified by the particles they transport, such as grains of rice), the ocean, or the surface of the sun.
How does convection current occur?
Convection currents form because a heated fluid expands, becoming less dense. As it rises, it pulls cooler fluid down to replace it. This fluid in turn is heated, rises and pulls down more cool fluid. This cycle establishes a circular current that stops only when heat is evenly distributed throughout the fluid.
Where do convection currents occur?
Convection currents occur within: the geosphere – plate tectonics. the atmosphere – wind. the hydrosphere – ocean currents.
Which layer of Earth does convection occur?
mantle
In which two layers do convection currents occur?
The two layers of the Earth that are involved in forming convection currents are the mantle and the outer core. b. Convection currents in the mantle are caused by the heat coming from the core and also the mantle.
Who introduced the concept of seafloor spreading?
Harry Hess
What was Arthur Holmes theory?
Holmes primary contribution was his proposed theory that convection occurred within the Earth’s mantle, which explained the push and pull of continent plates together and apart. He also assisted scientists in oceanographic research in the 1950s, which publicized the phenomenon known as sea floor spreading.
Who discovered slab pull theory?
Slab pull is that part of the motion of a tectonic plate caused by its subduction. In 1975 Forsyth and Uyeda used the inverse theory method to show that, of the many forces likely to be driving plate motion, slab pull was the strongest.
Why does slab pull occur?
The theory is that because the oceanic plate is denser than the hotter mantle beneath it, this contrast in density causes the plate to sink into the mantle. Slab pull occurs when an oceanic plate subducts into the underlying mantle.
Is a slab pull theory a form of convection?
The motion of tectonic plates is driven by convection in the mantle. There are three main forces that determine the rate at which tectonic plates move as part of the mantle convection system: slab pull: the force due to the weight of the cold, dense sinking tectonic plate.
What are the effects of slab pull?
“slab pull” As lithospheric plates move away from midocean ridges they cool and become denser. They eventually become more dense than the underlying hot mantle. After subducted, cool, dense lithosphere sinks into the mantle under its own weight. This helps to pull the rest of the plate down with it.
What causes ridge push and slab pull?
‘Ridge Push’ and ‘Slab Pull’ are thought to be the major forces driving the motion of oceanic plates. Ridge push is caused by the potential energy gradient from the high topography of the ridges. Slab pull is caused by the negative buoyancy of the subducting plate.
How do ridge push and slab pull work together?
Plate Driving Forces: The forces that drive the motions of tectonic plates at the surface. Slab Pull: The force exerted by the weight of the subducted slab on the plate it is attached to. Ridge Push: The pressure exerted by the excess height of the mid-ocean ridge.
What is the effect on a plate when a slab sinks?
As a slab sinks, it pulls on the rest of the plate with a force(slab pull). Plate tectonics has become the unifying theory of geology, it explains the connection between continental drift and the formation and destruction of crust along plate boundaries.
What drives the plate to move?
The heat from radioactive processes within the planet’s interior causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
What are the four driving forces behind plate motion?
Heat and gravity are fundamental to the process The energy source for plate tectonics is Earth’s internal heat while the forces moving the plates are the “ridge push” and “slab pull” gravity forces. It was once thought that mantle convection could drive plate motions.