Specific heat
The energy needed to raise 1 kg of a material by 1 K. Heat Q = m c change in T.
Last updated
Analogy
Water is slow to heat and slow to cool, like a heavy flywheel.
Example
c = 4186 J/(kg K)Q = 1 x 4186 x 10Q = 41,860 J
In practice
Warming 1 kg of water by 10 K takes about 41,900 J.
Practice
Flashcards
- What is the formula for heat needed to change temperature?Q = m c change in T.
Questions people ask
Why does sand get hot faster than water?
Sand has a specific heat of about 800 J/(kg K), roughly five times lower than water at 4186. The same sunlight raises the temperature of sand much more. This is why beaches burn your feet by noon while the sea stays cool, and why coastal climates are mild.
How do I solve a mixing problem?
Heat lost by the hot object equals heat gained by the cold one if nothing escapes. Write m c change in T for each side, set them equal, and solve for the final temperature. Remember the change in T is final minus initial, so the signs work out.