How much heat is needed to raise the temperature of 2.0 kg of water from 20 C to 80 C? The specific heat of water is 4186 J/(kg K). How does this compare with heating 2.0 kg of aluminium (c = 900 J/(kg K)) through the same rise? Solution: Q = m c delta_T = (2.0)(4186)(80 - 20) = (2.0)(4186)(60) = 502,320 J, about 5.0 x 10^5 J. For aluminium: Q = (2.0)(900)(60) = 108,000 J, only about one-fifth as much - water's high specific heat makes it far harder to warm.