|
The three main types of heat transfer are conduction, convection, and radiation. Each of these has its own properties and ways of transferring heat. The three types each have their own practical uses. Heat transfer is an interesting part of science that we have always known was there, but are just now beginning to understand. One of the types of heat transfer is conduction. Conduction is the most basic form of heat transfer. Conduction occurs when a form of energy is placed upon an object. The energy then starts vibrating the first particle. The first particle then bumps the second, and it starts vibrating.  This keeps happening until all the particles are vibrating. (this takes only minutes with most things), and the energy has transferred throughout the entire object, 'heating' it. A good example of this is if you touch a hot burner with your hand – the burner heats one side of your hand, then it heats right through it. The properties of conduction are: -The warmer particles are, the quicker they will vibrate. -The cooler particles are, the slower they will vibrate. -Things with many particles (e.g. metals) conduct heat better than things of equal size with fewer particles (e.g. gases). The second way to transfer heat is by convection. Convection is when a group of fluid particles are heated and rise, creating a gap that must be filled by other particles – this creates another gap, which must be filled. This creates a cycle. This cycle is not only a way of keeping rooms warm, it is also the reason that we have wind (and tornadoes.)  This is the easiest, most natural way of transferring heat. The properties of convection are: -For convection to occur, fluid particles must be present. -Liquids are poor conductors, gases poorer, but they support convection well. Convection is a good way to heat a building, but becomes not very practical when trying to cook. The third way to transfer heat is by radiation. Radiation is the transfer of energy in a wave-like form. Heat transfer by radiation is called "Radiant Energy." There are many different frequencies of radiation – the lowest is radio waves, the highest is gamma rays.  Radiant energy does not NEED anything to travel through. The properties of "Radiant Energy" are: -Travels at 300 000 000 m/s in a vacuum. -Is reflected by shiny objects -Is absorbed by dark objects (causing the particles to gain energy). -Radiant energy travels in straight lines Radiant Energy is a good way to heat something that you need heated quickly. These are three main types of heat transfer, all with their unique properties. Conduction is part of our everyday lives, ... one of its main uses is cooking. Convection is our main way of heating buildings, but it is also the reason we have wind. From cooking to helping to treat cancer, radiation has many uses. Understanding heat transfer has made our lives easier, and more practical. |