Question

Gas has to be above a certain temperature before it burns.
The diagram shows two similar wire gauzes, one made of iron wire and one made of copper wire.
Each is held over a Bunsen burner. When the gas supply is turned on and ignited below the gauze, the
effect is as shown in the diagram.
copper gauze
iron gauze


Observation:
flame appears both
above and below
the gauze


Observation:
flame only
appears below
the gauze
How can these observations be explained?​

Answer 1

It ignite below not above the gauze due to wire gauze is the heat sinker.

• The wire gauze is also know as the great heat sinker.
• Which means it absorbs the heat, which is provided to through thermal composition.
• When we put the wire gauze above the burner, the flame does not come up, is due to the property of heat sinking.
• When we put the burner above the wire gauze we will see the flame goes up.
• Now it depends upon the material used in the  wire gauze, in iron gauze the flame comes up which means the iron is not the good in holding the heat.
• But in copper gauze it is able to control the heat, that implies it depends upon the material used.