On your birthday, light candles and make wishes. There is a happy and charming atmosphere. It will be more interesting if you light a colored candle with bright colors such as red, yellow, blue, green and purple.
Why do colorful candles produce colorful flames? The secret lies not in paraffin wax, but in a thin candle wick. When making colored flame candles, their wicks were immersed in a metal salt solution. These metal salts can emit various colored lights at high temperatures. For example, sodium nitrate and sodium bicarbonate will emit yellow light, strontium nitrate will emit red light, barium nitrate will emit yellow and green light, copper chloride and copper sulfate will emit green light... This phenomenon is chemically called fireworks reaction.
This is because at high temperature, the outer electrons in the ground state of the atoms of these metal elements will transition to the high-energy excited state orbit, and the excited state atoms will then jump back to the ground state by emitting energy at a specific wavelength. If the wavelength of the emitted light falls in the visible region, it will show different colors.
In chemical experiments, flame color reaction is often used to detect the existence of a metal element, and in life, color flame candle is a good application. In addition, the colorful fireworks in the sky during the festival are also due to the addition of specific metal elements, which makes the fireworks more colorful when they are set off.