Difference between heat and temperature

In summary, temperature is a measure of heat energy per something, but the something is a little unusual - it's state.
  • #1
prane
23
0
I know there is a difference between heat and temperature as once I was told what it is. I remember it being very subtle and that's probably why I cannot remember the details anymore. Would anybody be so kind as to refresh my memory?
 
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  • #2
Yes. Temperature is a quantitative measure of a material's thermal energy. Heat is the transfer of thermal (internal) energy between materials.
 
  • #3
prane said:
I know there is a difference between heat and temperature as once I was told what it is. I remember it being very subtle and that's probably why I cannot remember the details anymore. Would anybody be so kind as to refresh my memory?

There is a good PF Library entry about Heat by user Hootenanny:

https://www.physicsforums.com/library.php?do=view_item&itemid=121

.
 
  • #4
cheers
 
  • #5
prane said:
I know there is a difference between heat and temperature as once I was told what it is. I remember it being very subtle and that's probably why I cannot remember the details anymore. Would anybody be so kind as to refresh my memory?
This isn't the way heat is described in introductory textbooks on physics. However, the following picture has helped me do thermodynamics problems with mathematics. If you are entering an advanced class in physics, maybe telling you this heuristic model will help more than refreshing your memory.
There is a fluid like quantity called entropy. It isn't a "real" fluid. On a microscopic scale, entropy is the same as disorder. However, entropy behaves like a indestructible fluid on a macroscopic scale. The unit of entropy is an energy unit divided by a time unit.
With the fluid properties of entropy in mind:
The word "heat" often refers to the entropy of a system.
Sometimes, the word "heat" refers to the energy carried by a flow of entropy rather than the entropy itself. In this case, the heat is measured in units of energy.
"Temperature" is the pressure that the entropy is under. Like a fluid spontaneously flows from high pressure to low pressure, entropy spontaneously flows from high temperature to low temperature. "Temperature" is in units of degrees, but really refers to a type of entropy pressure.
If it confuses you, ignore it.
 
  • #6
You can stick your hand in a 400 degree oven with no ill effects. That's not true if you stick it in a pot of boiling water. The water has more heat, although the air in the oven has a higher temperature.
 
  • #7
Vanadium 50 said:
You can stick your hand in a 400 degree oven with no ill effects. That's not true if you stick it in a pot of boiling water.

Yes agreed

The water has more heat, although the air in the oven has a higher temperature.

is that just a case of the water being more efficient at conducting the heat to the hand
than the air is ?

After all they say air is a poor conductor of heat

Just wondering :)

Dave
 
  • #8
prane said:
I know there is a difference between heat and temperature as once I was told what it is.
The most obvious difference is that temperature is an intensive property and heat is an extensive one. That is, if you have twice as much material at the same temperature it holds twice the heat.
You could get past that by changing your question to be the difference between temperature and heat per unit of substance (mass, volume, whatever...). In fact, temperature is a measure of heat energy per something, but the something is a little unusual - it's state. In an ideal gas, for example, there can be several states per molecule. For a monatomic gas, there are three energy states - velocities in the 3 dimensions. A diatomic gas also has spin about two axes, making 5 states. For statistical reasons, each state tends to have the same average energy, so a diatomic gas holds more heat energy than the same number of molecules of a monatomic gas at the same temperature.
 

What is the difference between heat and temperature?

Heat and temperature are often used interchangeably, but they are actually two different physical quantities. Heat is a form of energy that is transferred from one object to another due to a difference in temperature. Temperature is a measure of the average kinetic energy of the particles in a substance.

How are heat and temperature related?

Heat and temperature are related in that heat is the energy that flows between two objects when there is a temperature difference between them. The greater the temperature difference, the greater the amount of heat that is transferred.

What are the units of measurement for heat and temperature?

In the International System of Units (SI), the unit of measurement for heat is joule (J), while the unit of measurement for temperature is kelvin (K). In the United States, the unit of measurement for heat is still commonly measured in calories (cal), and temperature is measured in degrees Fahrenheit (°F).

Can an object have heat without having a temperature?

No, an object cannot have heat without having a temperature. Heat is a form of energy that is transferred between objects with different temperatures. If an object has no temperature, it means that its particles are not moving, so there is no energy available to transfer.

Why do objects with the same temperature feel different to the touch?

Objects with the same temperature can feel different to the touch because temperature is only a measure of the average kinetic energy of the particles in a substance. It does not take into account other factors such as density, mass, or specific heat capacity, which can affect how an object feels when touched.

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