why Covering the crucible with its lid as soon as the magnesium starts burning
When a crucible has been fired it is incredibly hot so the two most sensible reasons for using crucible tongs is firstly to prevent the users' hands from being burnt and secondly to prevent the bench in the laboratory from becoming damaged or burnt.
Oil from the fingers can contamine the surface of the crucible and lid
it is critical to set the lid just off the lip of the crucible to allow the evolved water molecules to escape on heating.
So you dont burn your self
A crucible is a container used for heating substances to high temperatures in laboratory settings. A lid is a cover that can be placed on top of the crucible to prevent the escape of substances during heating and to protect the contents from contamination. Together, they are used for controlled heating and chemical reactions in experiments.
why Covering the crucible with its lid as soon as the magnesium starts burning
You are describing a crucible. It is a heat-resistant container typically made of ceramic or metal that is used to heat chemicals to high temperatures, often in a laboratory setting. The lid helps to contain the heat and prevent any volatile substances from escaping.
When a crucible has been fired it is incredibly hot so the two most sensible reasons for using crucible tongs is firstly to prevent the users' hands from being burnt and secondly to prevent the bench in the laboratory from becoming damaged or burnt.
Oil from the fingers can contamine the surface of the crucible and lid
crucible
A crucible.
Crucible, pestle and mortar
it is critical to set the lid just off the lip of the crucible to allow the evolved water molecules to escape on heating.
The crucible is used for heating small quantities to very high temperatures.
So you dont burn your self
The porcelain crucible is used for calcination or melting.