Q. What is the main method of heat transfer in solids?

In summary, heat can be transferred by conduction in solids, but it is not the only method of heat transfer and is not very efficient in liquids and gases. The term "radiator" is not the most accurate description for the heating device in question, as it mainly heats through convection rather than radiation. It is important to critically evaluate information sources, as some may prioritize exam preparation over understanding the actual physics. A more reliable resource for learning physics is BBC Bitesize.
  • #1
Cliff Hanley
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From gcsescience.com;

"Heat can be transferred by conduction only in solids."

Q. Doesn't conduction take place directly prior to convection (when a radiator heats up a room)? If my cold hand came into contact with the warm radiator this would cause conduction; why isn't it the same for the cold air coming into contact with the warm radiator?

Q. Is it the case that 'radiator' isn't the most sensible term for the heating device in question given that, although it does radiate heat, it mainly heats up the room by causing convection?
 
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Yes, there is conduction in liquids and gasses (together known as fluids). It is not very efficient though. If you can engineer your system to prevent fluid circulation (think: layers of clothing, diving wetsuits), you end up with heat transfer only through radiation and conduction.
There's a bit more on that here and on the following page:
http://www.spaceflight.esa.int/impress/text/education/Heat Transfer/Conduction 01.html

The site you refer to appears to be using the simplifying approach of 'if it's small, ignore it completely'.
It's not the best approach, IMO, as it prevents one from seeing the actual physics (like how you've observed with the radiator), and seems to be geared for drilling in answers to exam questions rather than teaching physics.
Looking at your other threads, the site likes to speak authoritatively in that manner. Perhaps you'd be better off with a different resource for learning physics. You may still want to use that site in order to know what sort of answers the exams might expect, though.

Cliff Hanley said:
Q. Is it the case that 'radiator' isn't the most sensible term for the heating device in question given that, although it does radiate heat, it mainly heats up the room by causing convection?
Yeah, 'radiator' does not predominantly radiate. I think the name comes from the common-sense observation that 'heat radiates outward from it', rather than the actual physics of heating.
 
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  • #3
“If you can engineer your system to prevent fluid circulation (think: layers of clothing, diving wetsuits), you end up with heat transfer only through radiation and conduction.”

Q. So the warm air trapped between the layers conducts and radiates heat to the layer beneath and above?

“Perhaps you'd be better off with a different resource for learning physics. You may still want to use that site in order to know what sort of answers the exams might expect, though.”

Yes, thanks, I’m considering this already.“Yeah, 'radiator' does not predominantly radiate.”So there is conduction (but a small amount) between the surface of the radiator and the molecules of air coming into contact with it? What predominately heats the air to start it rising, ie, starts the convection process; radiation or conduction?
 
  • #4
Cliff Hanley said:

Q. Is it the case that 'radiator' isn't the most sensible term for the heating device in question given that, although it does radiate heat, it mainly heats up the room by causing convection?
It may heat the room by convection but it heats the persons in front of it mainly by radiation.
They are pretty bad at heating the room unless they are combined with a fan to circulate the air.
And then, the layer of air right next to the hot element is heated by conduction.

Maybe these statements are useful by making you think about their validity but you should not take them too seriously, especially if they are just about words.
 
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  • #5
Bandersnatch said:
Looking at your other threads, the site likes to speak authoritatively in that manner. Perhaps you'd be better off with a different resource for learning physics. You may still want to use that site in order to know what sort of answers the exams might expect, though.

BBC Bitesize is usually quite good at avoiding over-complication without simply ignoring reality: http://www.bbc.co.uk/bitesize/standard/physics/energy_matters/heat_in_the_home/revision/1/ "Conduction of heat energy takes place mainly in solids... In liquids and gases (fluids) heat energy is transferred mainly by a process called convection."
 
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  • #6
Cliff Hanley said:
From gcsescience.com;

"Heat can be transferred by conduction only in solids."


This is not correct.

Chet
 
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  • #7
Cliff Hanley said:
From gcsescience.com;

Based on what you've posted from this site so far, I'd suggest that you stop using it. :-p
 
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Related to Q. What is the main method of heat transfer in solids?

What is conduction?

Conduction is the transfer of heat or electricity through a material without any physical movement of the material itself.

How does conduction work?

In conduction, heat or electricity is transferred from one molecule to another through direct contact. The molecules with higher energy transfer their energy to the molecules with lower energy, creating a flow of heat or electricity.

What materials are good at conducting heat?

Metals, especially copper and aluminum, are great conductors of heat. They have free electrons that are able to move around and transfer energy easily. Other materials such as glass and ceramics are poor conductors of heat.

What is the difference between thermal conduction and electrical conduction?

Thermal conduction is the transfer of heat energy, while electrical conduction is the transfer of electrical energy. Thermal conduction occurs in solids, liquids, and gases, while electrical conduction only occurs in materials that have free electrons, such as metals.

How does conduction affect the temperature of an object?

Conduction can either increase or decrease the temperature of an object, depending on the direction of heat flow. If heat is transferred from a warmer object to a cooler object, the cooler object's temperature will increase. However, if heat is transferred from a cooler object to a warmer object, the warmer object's temperature will decrease.

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