Conduction, convection and radiation
examples of convection
Boiling Water Space heater in the room Air heating system.
what heat is and know what heat transfer exactly is
Heat is energy, specifically thermal energy and then heat transfer is the transfer of thermal energy through molecules
examples of conduction
Snowball in hand Hand touching a window Pot on a stove
examples of radiation
Toasting marshmallow on a fire Warming hands in a fire The sun warming the earth
describe molecular movement in convection
convection, on heating up the substance, it's molecules disperse and moves apart.
describe molecular movement in radiation
heat transfer mechanism in which no medium is required is called radiation. It refers to the movement of heat in waves, as it does not need molecules to travel through.
what happens during radiation and how it works
heat transfer mechanism in which no medium is required is called radiation. It refers to the movement of heat in waves, as it does not need molecules to travel through. The object need not be in direct contact with one another to transmit heat. Whenever you feel heat without actually touching the object, it is because of radiation.
describe molecular movement in conduction
molecules collide with surrounding molecules, making them vibrate too, resulting in the transportation of thermal energy to neighbouring part of the object.
process of convection currents.
As the space heater heats the air surrounding it near the floor, the air will increase in temperature, expand, and rise to the top of the room. This forces down the cooler air so that it becomes heated, thus creating a convection current.
what happens during convection, and how it works
on heating up the substance, it's molecules disperse and moves apart. When the convection is performed forcefully, the substance is compelled to move upwards by any physical means such as the pump. E.g. Air heating system. A space heater is a classic convection example. As the space heater heats the air surrounding it near the floor, the air will increase in temperature, expand, and rise to the top of the room. This forces down the cooler air so that it becomes heated, thus creating a convection current.
Conduction
the direct transfer of heat from one substance to another substance that is touching
Convection
the transfer of heat by movements of a gas or liquid
Radiation
the transfer of heat through space (no medium is needed)
what happens with conduction, and how it works
whenever two objects are in direct contact with one another, there will be a transfer of heat from the hotter object to the colder one, which is due to conduction. It happens when the temperature of the molecules present in a substance increase, resulting in vigorous vibration of the molecules. The molecules collide with surrounding molecules, making them vibrate too, resulting in the transportation of thermal energy to neighbouring part of the object.