Specific Heat (The Very Concept)

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Specific heat is defined as the amount of heat needed to raise the temperature of a unit mass of a substance by one degree compared to water. In the example of a 50-lb ball of iron heated to 200 degrees, the total heat required is calculated using the specific heat of iron (0.11), resulting in 50(0.11)(200) instead of 50(200). This means that to achieve the same temperature change, iron requires significantly less heat than water due to its lower specific heat. The discussion highlights the importance of understanding specific heat in thermodynamic calculations. The excitement about grasping this concept reflects the learning process involved.
aleph_0
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So I don't get the concept of specific heat. I'm doing an ODE problem and I've never even looked at science, not even in high school. The book defines the specific heat of a substance as: The ratio of the quantity of heat required to raise the temperature of a unit of substance by one degree, to the quantity of heat required to raise the same unit of water by one degree.

Now take for instance a 50-lbs ball of iron heated to 200 degrees, where iron has a specific heat of .11. A priori I would have thought that the total quantity of heat would be 50(200) because, hey, temperature is like average quantity of heat in an object, right? And the object weighs 50-lbs, which can basically be treated like its mass. So the product should give the total heat, no? Huh? Right?

Well I would be wrong. It looks like the quantity of heat in such an object is 50(.11)(200) and I don't exactly get why. What in god's name does that ratio have to do with this sort of thing?

Thank you.
 
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hi aleph_0! welcome to pf! :smile:

it means that if you need X amount of heat to raise 50-lbs of water by 200°, then you only need 0.11 times X to raise 50-lbs of iron by 200° :wink:
 
OH MY GOD that was the perfect answer! So clear, so simple. THANK YOU!

(Part of this is general excitement about learning a concept; the other part is too much coffee.)
 
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