Convection, Conduction, Radiation

In summary, convection is the transfer of heat between a solid object and a fluid by means of the fluid passing by the object. It can be either natural or forced, with the latter being caused by a fan or other force. In the case of the person tanning with a drink and a fan, the warm air from the fan moves over the person's skin, exchanging heat and causing forced convection.
  • #1
Dberry
18
0
In my book I'm reading about heat, specifically convection. There is an image of a person with a drink in their hand, suntanning while a fan blows on them. I get that the drink represents conduction, the sunlight is radiation, but how is the fan convection?
 
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  • #2
When a fluid passes by a solid object of different temperature, heat passes to or from the solid ojbect to the fluid by means of convection. Convection can be either natural or forced. With wind, it is forced. With still fluid but different temperatures, there is a change in the density of the fluid at the solid. That causes natural convection.
 
  • #3
There is natural convection inside the drink cup due to the difference in temperature between the container wall and neighboring fluid.
 
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  • #4
I still don't understand. Can someone dumb this down for me?
 
  • #5
I have the definition and examples of convection in my book. I guess the air is the build medium but how is the fan blowing on the tanning person convection? Where is the warm air and where is the air moving?
 
  • #6
by build I meant FLUID
 
  • #7
Dberry said:
I have the definition and examples of convection in my book. I guess the air is the build medium but how is the fan blowing on the tanning person convection? Where is the warm air and where is the air moving?

I might be wrong so if i am LawrenceC correct me

Conduction is when particles pass on heat by vibrating at their places
Convection is when instead of vibrating the particles move to exchange heat ... as in case of fan !
 
  • #8
Dberry said:
I have the definition and examples of convection in my book. I guess the air is the build medium but how is the fan blowing on the tanning person convection? Where is the warm air and where is the air moving?

The temperature of the ambient air (fluid) is different from the surface temperature of the human body. Therefore the fluid being pushed over the skin's surface by the fan will exchange heat with the body, either warming it or cooling it. Because there is a fan, the convection is considered forced convection. If the fluid is moving only due to density differences, the convection would be called natural convection.
 

Related to Convection, Conduction, Radiation

1. What is the definition of convection?

Convection is the transfer of heat energy through the movement of a fluid (such as air or water) due to differences in temperature or density. This can occur in both liquids and gases.

2. How does conduction differ from convection?

Conduction is the transfer of heat energy through direct contact between two objects or substances. Unlike convection, it does not involve the movement of a fluid, but rather the transfer of kinetic energy between molecules.

3. What is an example of radiation?

One common example of radiation is the transfer of heat energy from the sun to the Earth through electromagnetic waves. Other examples include the heat emitted from a fire or a light bulb.

4. How does convection impact weather patterns?

Convection plays a significant role in shaping weather patterns. As warm air rises and cool air sinks, convection currents are created, which can lead to the formation of clouds, precipitation, and other weather events.

5. How can convection be utilized in practical applications?

Convection can be used in various ways, such as in heating and cooling systems, cooking, and even in industrial processes. For example, convection ovens use fans to circulate hot air, which cooks food faster and more evenly.

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