Cold objects put out less heat or infrared light and appear less bright in the infrared. Anything which has a temperature puts out heat or infrared light. In the infrared images shown below, different colours are used to represent different temperatures. You can find out which temperature a colour represents by using the colour-temperature scale show to the right of most of the images. The temperatures are in degrees Fahrenheit.
To the left is an infrared image of a metal cup holding a very hot drink? You might of notice the rings of colour showing heat traveling from the liquid through the metal cup. You can see this in the metal spoon as well. To the right is an infrared image of a melting ice cube. Notice the rings of colour showing how the melted water warms as it travels away from the cube. Although the ice cube is cold, it still puts out heat, as you can see by matching the colour of the ice cube with its temperature.
Ultraviolet: UV light, short for Ultraviolet Light is a type of light energy making up of one part of the electromagnetic spectrum, which spectrum includes gamma and x-rays. UV light visible light, infrared rays, microwaves, and radio waves, listed in order of decreasing frequency and increasing wavelength. UV light therefore has a wavelength shorter than that of the visible light, and cannot be detected by the human eye. Whereas UV light itself is invisible, it causes many matters to glow or fluoresce in a variety of colours