Specific heat capacity: Q = mcΔT

0:00How much energy does it take to warm 200 grams of water?

0:05Water is made of tiny particles that are always moving.

0:09A thermometer measures temperature: the average kinetic energy, or energy of motion, of the particles.

0:18Heat is energy that flows because of a temperature difference: here, from the hot heater into the water.

0:25As heat flows in, the particles move faster on average and the temperature rises.

0:31So heat and temperature are not the same: heat is energy on the move, temperature measures average kinetic energy.

0:40The heat needed is Q equals m times c times delta T.

0:46Q is the heat, in joules, and m is the mass, in grams.

0:52c is the specific heat capacity: the energy to warm 1 gram by 1 degree Celsius.

0:59Water's c is 4.18 joules per gram per degree Celsius, which is very high.

1:06Delta T is the temperature change: our water warmed by 10 degrees.

1:12So for our water, Q is 200 times 4.18 times 10, which is 8,360 joules.

1:22Now give the same 8,360 joules to 200 grams of iron, whose c is only about 0.45.

1:31To find delta T, divide Q by m times c: 8,360 divided by 200 times 0.45.

1:42The iron warms by about 93 degrees, over nine times as much as the water.

1:49Water's high c means oceans warm and cool slowly, which helps keep coastal weather mild.

1:57In short: heat equals mass times specific heat capacity times temperature change.