The essence of flame is a high-temperature gaseous or plasma substance. There are two factors that determine the color of the flame:
1, the temperature of the flame determines the color of the flame, and the flame is a reaction.
When the temperature is low, it is infrared. With the increase of temperature, the flame changes from red orange (3,000 degrees) to yellow white (4,000 degrees), blue blue (5,000-6,000 degrees) to purple (above 7,000 degrees), and finally invisible ultraviolet (tens of thousands of degrees), and the color is constantly changing.
From the point of view of high-energy physics, the flames in infrared and color spectra are low-energy flames. With the increasing temperature, the color of the flame ranges from ultraviolet rays to X rays to gamma rays. These are indescribable "colors".
2. The elemental composition of gaseous and plasma substances determines the natural spectrum of the flame, and each element in the element list will emit its own specific light color at high temperature.
For example, sodium is yellow, potassium is purple, copper is green, and the light color of the compound is variegated, because there are many kinds of luminescent elements. This is why the colors of various flames are different.
Brief introduction of flame
Flame is a state or phenomenon. The burning combustible gas glows, releases heat and flashes upwards. Combustible liquid or solid must be changed into gas before it can be burned to produce flame.
The main reason is that combustible gas is oxidized by air or pure oxygen, giving off light and heat. Some substances don't necessarily need oxygen to burn. For example, active magnesium can be burned in carbon dioxide and nitrogen.