it comes in contact with air
it goes dark because it reacts with the air.
dull
Sodium is shiny, but it reacts very quickly with oxygen in the air to form lithium oxide, which is a dull black color.
have no idea
Dull Black Surfaces
it goes dark because it reacts with the air.
After my opinion the fresh surface of copper is not dull.
dull
Sodium in its natural state is shiny, like most metals. When sodium interacts with oxygen in the air, it become sodium oxide, which is much more dull. As a result, when you cut into a piece of sodium, you reveal a brand new part of the sodium that has not yet become sodium oxide and is still shiny.
When you cut the likes of sodium or potassium it leaves a shiny surface which will quickly turn dull as they react with Oxygen in the air. To prevent them reacting with any of the air, these elements are usually kept in oil.
reacts with air
Dull surface is a better absorber. A shiny surface would better reflect than absorb.
Sodium is shiny, but it reacts very quickly with oxygen in the air to form lithium oxide, which is a dull black color.
matte
A dull surface will absorb infrared best, but it needs to be dull at infrared wavelengths. Do not judge the infrared behavior by the visible performance.
because soduim turns metals dull
have no idea