2. Bunsen Burner
1. The bunsen burner is used in the laboratory to heat
substances.
2. The bunsen burner has an air-hole. The air-hole can be
opened or closed by turning the collar.
3. When the air-hole is opened, the Bunsen burner gives a
blue flame. This is called a non-luminous flame. The
flame is very hot because the gas is burned completely.
4. When the air-hole is closed, the burner gives a yellow
flame. This flame is easier to see and it is called a
luminous flame. This flame is less hot and produces a
lot of black soot because the gas is not burnt
completely.
3. 5. The correct way of
using a Bunsen
burner:
Close the air hole
completely by turning the
collar.
Hold a lighted match or
wooden splinter near the
mouth of the barrel.
Turn on the gas slowly.
When the flame is seen,
slowly open the air hole
by turning the collar.
4. The Bunsen burner gives different flames:
Luminous Flame Non-luminous Flame
when the air hole is closed
yellow flame
easy to see
produces a lot of black soot
shape changes
not very hot
incomplete burning
not usually used for heating
when the air hole is opened
blue flame
not easy to see
does not produce soot
constant shape
very hot
complete burning
suitable for heating