1.3 Heat Energy & Temperature
It is important to understand the difference between heat and temperature.
Heat, as we saw in Section 1-1, is the amount of kinetic energy in a sample of matter. It flows in the direction from the warmer object to the colder object.The SI unit of energy, including heat energy, is the joule (J), and is formally defined as the amount of energy produced when a force of one newton acts over a distance of one meter. How much energy is one joule?
[You may also be familiar with another unit of heat energy, the calorie (cal). To read a bit more about the calorie, follow this link.]
Temperature is a measure of the average kinetic energy of a sample of matter. It is the intensity of heat energy.
Temperature is measured in degrees celsius (°C) or in kelvin (K). Kelvin is the SI temperature scale. You may already know that at the temperature known as absolute zero (0 K), particle motion is as slow as it can possibly be. That's as cold as you can theoretically get!
Research
What is the coldest temperature scientists have been able to achieve in the lab?
To convert between celsius and kelvin:
°C = K - 273 K = °C + 273
Convert 25°C into Kelvin.
K = 25°C + 273 = 298 K
(the degree symbol is not used with K)
Convert 500 K into degrees celsius
°C = 500 K - 273 = 227°C
Lab Activity
sample data provided
This link will take you directly to the heating & cooling lab. The Lab Link at the top of the page takes you to the main laboratory section.
Purpose: To help you understand the relationship between kinetic energy and temperature, and the conversion between kinetic energy and potential energy during phase changes from the solid to liquid states.
If you are not able to carry out the lab exercise, a sample set of data is provided in the lab.
This link describes the molecular events that occur during changes of state.