Question 32

[rs53]

Is there any easy way to remember conduction, convection, and radiation? I'm honestly a bit confused about what exactly convection is. Thanks!

[admin]

Well you know the expression "conduct electricity" which implies that conduction requires a material medium (ie a copper wire) which implies physical contact.

You also know the word radiation which can occur from a nuclear weapon or even the sun "radiates light". Now if the sun can radiate light from accross space (which essentially has no particles like a vacuum) then radiation does not need a material medium.

I guess convection is the only word that is not commonly used but it is based on a very straightforward concept: hot fluids/gases rise, cooler ones descend. Thus if you heat from the bottom then you get a circulation of fluids or gases (like heating water in a closed pot on your stove). When the hot fluid/gas rises, it also warms up the cooler fluid/gas which is descending.

[klee92181]

Radiation- waves (ex. sunlight heating you up)

Conduction- direct physical contact (hand on stove)

Convection- requires a moving fluid (ex. circulating air). To give a more specific example, as your body releases heat, this heat is carried away by the colder circulating air around you (hence moving fluid) and therefore your body cools down.

[bzhou2033]

Hi, could you reword the problem please. I had a really tough time with the ambiguity. It could read as

1. aid, via which of the processes, preventing heat gain

or

2. aid in preventing (heat gain which is a result of one of these processes)