I. Conduction (Transfer of energy in a medium while the medium stays unmoved.)

Concepts of conduction:

1. A medium is needed for energy transfer but the medium definately does not move. --------------------------------------------------------------- ------------------------------------------------
2. Different materials affect the conduction rate. Think about: Insulator, Conductor. :} -------------------- ----------------------------------------------------------------------------------------------
Good conductors: Metals ; Copper,silver,iron.
Good insulators: Non-mentals ; Plastic,metal,wood,brick. (I think you get the idea, right?) --------------------------------------------------------------- ------------------------------------
3. The difference is that metals Do have spare electrons while non-metals don't.

4. So what happens is when thermal energy is present, molecules from the end vibrate and collide to the rest, causing all to vibrate. ---------------------

5. The spare elections in metals gain K.E too, and move faster. Now you know why conductors transfer heat energy so fast - They're not called conductors for show:) ------ ---------------------------------------------------------------------
6. Lastly, Solids conduct energy much faster than gas cause of the spacing they have.

Below is an example of an experiment regarding conduction:)

1.It only applies for Liquids and Gases, but not solids.

2. Since it applies for 2, I will illustrate my point with an 'A' so it can be applied for both liquids and gas.

Tiko Bear is a retarded bear, and one day, he decides to play with fire. He heats A. A expanded and produced B. B is hot and less dense than the surrounding, so it rises up. A, being heavy and cool, sinks down. This movement sets up a convectional current, due to difference in density. Tiko bear was so happy with what he saw that he laughed so hard till he died. D: (Sorry.)

Here's a video of an experiment to prove convection currents. It's actually a physics lesson and the experiment is done by the rather humorous teacher. If you have 3 minutes to spare, you can try watching this. :)

The end. So hence, Convection is just the transfer of energy by means of currents in a fluid.

III. Radiation

Concepts of radiation:


1.It is the emission of infrared waves from the surface of bodies w/o a medium.

2. It can take place in vacuum.

3. Your knowledge tells you not to wear black when the weather's hot. This is because Colour affects radiation.

4. Dull surfaces absorb better than a shiny cinderella shoe.

5. Surface temperature affects the rate of infrared.

6. Larger surface area will result in a higher rate of infrared radiation.

IV. Applications of Thermal Energy Transfer.

I'm not tellin' you anything! Go find them in your kitchen! (No la, i know you also 不稀罕 lor.）But i still have to say it, Sorry :D

*Updated:D*
Considering the fact that the applications are really important, i shall update this:\

1. Conduction!

-The uses of good conductors of heat like : Cooking utensils, iron rods and heat exchangers. This is because they are made up of metals which means good conductors of heat, which further means that heat can be travelled quickly through these conductors.

-The uses of good insulators of heat like : Handles of appliances (Surely you don't want to get burnt:), Table mats, Sawdust, wooden ladles, woollen clothes etcetc :D

2. Convection!

-Common applications include:

• Electric kettles: (The heating coil is placed at the bottom so as to aid the transfer of thermal energy in water by convection.)
• Air conditioners: Ever wondered why air conditioners are always placed on top of the room? That is because of the setting up of convectional currents such that warm air and cool air can rotate.
• Refriderators: Freezing unit is placed at the top to facilitate the setting up of convection currents.

3. Radiation!

-Common applications:

• Teapots (Shiny teapots can keep tea warm for a longer time and keep cool liquids for a longer time:)
• Greenhouse (Infrared radiation from the sun passes through the glass roof, it warms up the soil and plants in the greenhouse. In addition, the infrared radiation emitted by the contents gets trapped and the temperature increases over time.)
• Vacuum flasks. Minimize heat lost by conduction, convection,radiation and evaporation.

Sayonara:D