Specific heat capacity and heat capacity?

In summary, the difference between specific heat capacity and heat capacity is that specific heat capacity takes into account the mass of the object, while heat capacity does not. Both measure the amount of energy stored in an object, but specific heat capacity is calculated per unit of mass. The amount of energy delivered by an object depends on its temperature change, mass, and a constant specific to the material. This is why a spark, despite being hotter, does not cause as much injury as a Bunsen burner stem, which has a higher mass and thus more energy to deliver.
  • #1

threy

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A spark does not cause injury when it strikes the skin of a child. If you touch the burning stem, it can cause severe burn on your fingers? WHY?

What's the difference between specific heat capacity and heat capacity?
 
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  • #2
threy said:
What's the difference between specific heat capacity and heat capacity?
The specific heat capacity is the heat required to change the temperature of a substance by a certain temperature interval.

The heat capacity of a substance is a measure of how well the substance stores heat. When heat supplies to a material, it will cause an increase in the material's temperature. The heat capacity is defined as the amount of heat required per unit increase in temperature.

http://en.wikipedia.org/wiki/Heat_capacity
 
  • #3
If you are shot by a gun it's not the mass of the bullet that matters it's the energy it delivers when it hits you. Even a small object like a bullet can contain a lot of energy if it's traveling really fast.

"burning stem" = Bunsen burner stem?

So regarding the spark vs Bunsen burner stem...

What causes injury is not just the temperature of the object but the amount of energy it delivers to the person.

The amount of energy released by an object = The temperature change * The amount of stuff * A constant that depends on the material.

So when a metal spark hits you it might well cool from say 1000C to body temperature but because the amount of stuff (the amount of mass) is very low the energy it contains/delivers is also very low.

The Bunsen burner stem might not be as hot as the spark but it has much greater mass so it is able to deliver more energy to your body.

Regarding the constants...

Heat Capacity is the amount of energy (in Joules) stored in an object per degree temperature rise. It takes into account the mass of the object (eg the mass of the metal in the spark).

Specific Heat Capacity is the same as the Heat Capacity BUT it is calculated "per unit of mass". This makes it more useful because it allows you to calculate the amount of energy in any size lump of metal simply by multiplying by the mass of metal.

So in short one takes into account the mass and the other doesn't.
 
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  • #4
ps There are other versions of the Specific Heat Capacity. In some situations it might help to know the "volumetric specific heat capacity" which is the amount of energy per degree per unit volume of the material. To calculate the energy stored you would multiply by the volume rather than the mass.
 

1. What is the difference between specific heat capacity and heat capacity?

Specific heat capacity is the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius, while heat capacity is the amount of heat required to raise the temperature of the entire sample by 1 degree Celsius. In other words, specific heat capacity is per unit mass, while heat capacity is for the entire sample.

2. How is specific heat capacity measured?

Specific heat capacity can be measured using a calorimeter, which is a device that measures the amount of heat absorbed or released during a chemical or physical process. The change in temperature and mass of the substance can be used to calculate its specific heat capacity.

3. What factors affect specific heat capacity?

The specific heat capacity of a substance is affected by its mass, temperature, and the type of substance. Generally, substances with higher mass and lower temperature have higher specific heat capacities, and substances with stronger intermolecular forces have higher specific heat capacities.

4. How does specific heat capacity relate to energy transfer?

Specific heat capacity is a measure of how easily a substance can absorb or release thermal energy. Substances with higher specific heat capacities require more energy to change their temperature, while substances with lower specific heat capacities require less energy.

5. What are some real-life applications of specific heat capacity?

Specific heat capacity is an important concept in industries such as food and beverage, where precise temperature control is necessary for cooking and refrigeration processes. It is also used in engineering and construction to design buildings and materials that can withstand extreme temperatures without significant changes in their thermal properties.

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