Convection is heat transfer due to a density differential within a fluid . As water’s temperature increases in the presence of a heat source, it will become less dense and rise. As it moves up and away from the heat source, it cools and becomes more dense and sinks. ... Air from above the ocean is colder and more dense.
Does change in density cause convection?
Convection currents (sometimes also called “density currents”) result from differences in density of a substance, and density can be altered by changing the temperature, salinity, or pressure of a substance . Less dense substances RISE, while more dense substances SINK.
What is the role of temperature in convection?
Steps to the Process of Convection
As the ground’s temperature warms, it heats the layer of air directly above it through conduction (the transfer of heat from one substance to another). ... The stronger the surface heating, the stronger and higher up into the atmosphere the convection extends.
Does temperature affect convection?
Convection works by areas of a liquid or gas heating or cooling greater than their surroundings, causing differences in temperature . These temperature differences then cause the areas to move as the hotter, less dense areas rise, and the cooler, more dense areas sink.
How does density play a role in plate tectonics with convection currents?
Convection occurs through the movement of particles. As particles become heated, the molecules move faster and faster, and as molecules move apart, density decreases . The warmer, less dense material rises compared to the surrounding cooler, higher density material.
What is the relationship between density and convection?
Convection is heat transfer due to a density differential within a fluid. As water’s temperature increases in the presence of a heat source, it will become less dense and rise . As it moves up and away from the heat source, it cools and becomes more dense and sinks.
Can you have convection if two liquids have the same densities?
Two liquids that have the same volume don’t necessarily have the same density . Density = mass/volume, so they would only have the same density if they also have the same mass. Density is an intensive property, which means that it doesn’t depend on the amount of the substance present.
What is convection of heat with example?
Everyday Examples of Convection
boiling water – When water boils, the heat passes from the burner into the pot, heating the water at the bottom. This hot water rises and cooler water moves down to replace it, causing a circular motion. ... ice melting – Ice melts because heat moves to the ice from the air.
What are 4 examples of convection?
- Breeze. The formation of sea and land breeze form the classic examples of convection. ...
- Boiling Water. ...
- Blood Circulation in Warm-Blooded Mammals. ...
- Air-Conditioner. ...
- Radiator. ...
- Refrigerator. ...
- Hot Air Popper. ...
- Hot Air Balloon.
What happens to cold air in convection?
Water vapor carried in by convection condenses, releasing tremendous amounts of energy. This energy causes the air to expand and rise , where it is colder. More condensation occurs in these colder regions, which in turn drives the cloud even higher.
How does convection lose heat?
Convection – Heat loss by air or water moving across the skin surface . When exposed to cold air, cover exposed skin and take shelter from the wind. The thicker the insulating clothing layer, the better it prevents convection.
Why does heat rise in convection?
Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. Convection above a hot surface occurs because hot air expands, becomes less dense , and rises (see Ideal Gas Law).
How do you calculate heat transfer in convection?
- 1 W/(m 2 K) = 0.85984 kcal/(h m 2 ° C) = 0.1761 Btu/(ft 2 h ° F)
- 1 kcal/(h m 2 ° C) = 1.163 W/(m 2 K) = 0.205 Btu/(ft 2 h ° F)
- Btu/hr – ft 2 – °F = 5.678 W/(m 2 K) = 4.882 kcal/(h m 2 ° C)
What is best explained by plate tectonics?
The theory of plate tectonics states that the Earth’s solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere, the molten upper portion of the mantle. Oceanic and continental plates come together, spread apart, and interact at boundaries all over the planet.
What are the 3 causes of plate movement?
Mantle dynamics, gravity, and Earth’s rotation taken altogether causes the plate movements. However, convectional currents are the general thought for the motion.
What causes the tectonic plates to move?
Earth’s crust, called the lithosphere, consists of 15 to 20 moving tectonic plates. ... 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.
