It's the amount of heat you need to pump into 1 gram of the substance in order to raise its temperature 1°C.
Different substances can have some wildly different values of specific heat. The specific heat of water, potatoes, and rocks are especially high. That means that those substances 'hold' a lot of heat ... which is why, before electric heating pads were invented, rubber bags with these substances were used to warm up a cold bed or to reduce the pain in a sore muscle.
Specific Joules: heat of: per gm-°C
Lead 0.13 Copper 0.38 Iron 0.45 Aluminum 0.9 Water 4.2 Helium 5.2 Hydrogen 14.3
Don't quite understand the idea yet ? Here's one way I like to think of it:
Here I have a soda straw, with the bottom end closed and some water in it. How much water would you have to add to the straw to fill it 1 inch higher ? Not much, right ?
OK. Now, here I have a beer barrel that's maybe about half full of water. How much water would you have to add to the barrel to fill it 1 inch higher ? MORE than the soda straw, right ?
OK. Now, here I have an olympic swimming pool with some water in it. How much water would you have to add to the pool to fill it 1 inch higher ? A lot ? I agree. How much ? I don't know. But definitely MORE than the straw or the barrel.
This is the way I understand specific heat:
-- The AMOUNT of water is like the heat-energy in the substance. -- The DEPTH of the water is like the temperature of the substance. -- The more water you pour into it, the deeper it gets. -- The more heat you pour into it, the warmer it gets. -- But some substances are "wider" than others. . . . . . Lead is very skinny, like the straw. 0.13 joule of heat added to a gram of it is enough to raise it 1°C. . . . . . Water is a 'fatter' substance, like the barrel. You have to pour 4.2 joules into a gram of it, to raise it 1°C. . . . . . Hydrogen is incredibly fat, like the pool. You have to pour 14.3 joules into 1 gram of it, to raise it 1°C.
==> Hydrogen needs 110 times as much heat energy added as Lead needs, to make 1 gram of each substance 1°C warmer than they are now. The specific heat of Hydrogen is 110 times the specific heat of Lead !
Answer: A device records the time it takes sound waves to travel from the surface to the ocean floor and back again. Sound waves travel through water at a known speed. Once scientists know the travel time of the wave, they can calculate the distance to the ocean floor.
