Convection currents drive the movement of Earth’s rigid tectonic plates in the planet’s fluid molten mantle. In places where convection currents rise up towards the crust’s surface, tectonic plates move away from each other in a process known as seafloor spreading (Fig. 7.21).

Convection currents are also responsible for the movement of Earth’s plates- a process known as plate tectonics. The magma in the mantle is heated up at the lower portions of the mantle, and then the heated magma rises up and ends up pushing on the plates, causing them to move.

Convection currents in the magma drive plate tectonics. Large convection currents in the aesthenosphere transfer heat to the surface, where plumes of less dense magma break apart the plates at the spreading centers, creating divergent plate boundaries.

Magma is the molten rock below the crust, in the mantle. Tremendous heat and pressure within the earth cause the hot magma to flow in convection currents. These currents cause the movement of the tectonic plates that make up the earth’s crust.

It is true that the convection currents produce the heat in the Earth’s interior. The correct answer is True.

This flow, called mantle convection, is an important method of heat transport within the Earth. Mantle convection is the driving mechanism for plate tectonics, which is the process ultimately responsible for producing earthquakes, mountain ranges, and volcanos on Earth.

Convection currents are part of what drives global circulation of the Earth’s atmosphere. Convection currents in the air and sea lead to weather. Magma in the Earth’s mantle moves in convection currents. The hot core heats the material above it, causing it to rise toward the crust, where it cools.

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. The liquid or gas in hot areas is less dense than the liquid or gas in cold areas, so it rises into the cold areas. The denser cold liquid or gas falls into the warm areas.

There are two types of convection: natural convection and forced convection. Natural convection is produced by density differences in a fluid due to temperature differences (e.g., as in “hot air rises”).

In conduction, heat transfer takes place between objects by direct contact. In convection, the heat transfer takes within the fluid. The heat transfer occurs through a heated solid object.

While conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter; radiation is the transfer of energy with the help of electromagnetic waves. The matter is present around us, in three states, solid, liquid and gas.

Heat is thermal energy. It can be transferred from one place to another by conduction. Metals are good conductors of heat, but non-metals and gases are usually poor conductors.

Example of situation with conduction, convection, and radiation

• Conduction: Touching a stove and being burned. Ice cooling down your hand.
• Convection: Hot air rising, cooling, and falling (convection currents)
• Radiation: Heat from the sun warming your face.

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. radiator – A radiator puts warm air out at the top and draws in cooler air at the bottom.

Radiation Examples

• ultraviolet light from the sun.
• heat from a stove burner.
• visible light from a candle.
• x-rays from an x-ray machine.
• alpha particles emitted from the radioactive decay of uranium.
• sound waves from your stereo.
• microwaves from a microwave oven.
• electromagnetic radiation from your cell phone.

Everyday Examples of Heat or Thermal Conduction

• You can warm your back muscles with a heating pad.
• The heat from a hot liquid makes the cup itself hot.
• If you are cold and someone holds you to warm you, the heat is being conducted from their body to yours.

The EM spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The common designations are: radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.

Radiation

• electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ)
• particle radiation, such as alpha radiation (α), beta radiation (β), proton radiation and neutron radiation (particles of non-zero rest energy)

Gamma rays

alpha particles

Solar radiation includes visible light, ultraviolet light, infrared, radio waves, X-rays, and gamma rays.

The three most common types of radiation are alpha particles, beta particles, and gamma rays.

Alpha, beta and gamma