Register to reply

Equating Heat and Einstein's equation confusion

Share this thread:
pjbeierle
#1
Dec5-13, 01:17 PM
P: 7
I should start by saying that I am a bit embarissed by asking such a silly question
By simply equating the mass-energy formula with the temperature dependence of heat...

M*c2 = M* cm *ΔT

it strikes me as odd that the mass cancels,

c2 = cm *ΔT

I was doing this in order to calculate how much mass is gained by heating say a cup of water up by a specific amount (I know it would be very small, but I was just curious of the order of magnitude). But it seems I cannot do this, so there must be something obvious I am missing.
Phys.Org News Partner Physics news on Phys.org
'Squid skin' metamaterials project yields vivid color display
Team finds elusive quantum transformations near absolute zero
Scientists control surface tension to manipulate liquid metals (w/ Video)
russ_watters
#2
Dec5-13, 01:33 PM
Mentor
P: 22,313
They don't cancel because they are two different masses. On the left is the mass equivalent of the energy and on the right is the rest mass of the water.
DrGreg
#3
Dec5-13, 02:35 PM
Sci Advisor
PF Gold
DrGreg's Avatar
P: 1,849
Quote Quote by russ_watters View Post
They don't cancel because they are two different masses. On the left is the mass equivalent of the energy and on the right is the rest mass of the water.
...or to put it another way, the equation should be
[tex]\Delta m \, c^2 = m \, c_m \, \Delta T[/tex]


Register to reply

Related Discussions
Confusion with Einstein tensor notation Calculus & Beyond Homework 4
Equating differentials => equating coefficients Classical Physics 9
Help! confusion on heat transfer. Introductory Physics Homework 1
Equating solar power to usable heat Classical Physics 8
Einstein Specific Heat Advanced Physics Homework 0