Energy and temperature
Internal energy is linked to the temperature of matter but the two are very different things:
- The total kinetic energy and potential energy of the particles in an object. is a measure of the total energy of all the particles in the object or substance. This includes the Energy which an object possesses by being in motion. of the particles and A type of energy store. It is taken in when chemical bonds break, and given out when chemical bonds are made. of the bonds between them.
- A measure of the average kinetic energy of particles in a substance. is a measure of the average speed of the particles. This is based on the kinetic energy of individual particles.
Heating water causes the water A collection of two or more atoms held together by chemical bonds. to gain kinetic energy and speed up. It takes more energy to raise the temperature of a large amount of water because more molecules need to have their speed changed.
In the diagrams above the two beakers have been heated by the same Bunsen burner for the same amount of time, so both have been given the same amount of energy. However, the smaller beaker has had a bigger temperature rise because the same energy has been given to a smaller number of particles so each particle is moving faster than those in the other beaker.
Example
Imagine a teaspoon of boiling water at 100 degrees Celsius (°C) and a large bowl of water at room temperature:
- the teaspoon of hot water would not be able to melt an ice cube - even though the particles have lots of kinetic energy, there are very few of them
- the bowl of room temperature water would be able to melt an ice cube - even though each individual particle has less kinetic energy, there are many more of them, making the total available energy much larger