When the air hole is closed, the flame is a luminous flame. This flame is not ideal for heating for the following reasons: it is not as hot as the non-luminous flame it is very unstable it produces a lot of soot thus, only non-luminous flames (the blue one) is ideal for heating. :)
There are different reasons for flames being yellow and the properties depend on the reason.
Thermostats are used to keep a constant. They maintain the 'ideal' conditions For example: - if you set your heating to come on at 20deg the thermostat will turn the heating on if the temp falls below your ideal 20 degree temperature. Once it has reached the ideal it will turn the heating off again.
on heating,free electrons occupy spaces created by loss of oxygen from zno and turn yellow :)
its highly visible and cooler than other coloured flames
Iron
The two types of flames a Bunsen burner can produce are a luminous, yellow flame and a "roaring" blue flame. The blue flame is much hotter than the yellow flame.
* Yellow safety flame - Safe becasue you can see it easily and know it is there. Not used for heating because it creates soot. * Silent blue flame - Used to for gental heating and is silent and not very visible. * Roaring blue flame - Strongest heating setting and is made of two cones. The outside cone is the flame and it is blue , the inside cone is unburned gas that is purple.
because yellow flames dont burn effectively and leave carbon so burning with yellow flames leaves soot on the glassware
One can purchase fully functional ideal boilers of many different varieties from Ideal Heating. Many boiler parts and spares can be found at Ideal Parts as well.
The hotter the flame, the less color (and light) given off. Bright, yellow flames are the result of carbon that has not been burned, where blue flames indicate a near total burning of the fuel. Other chemicals present in the wood can color flames- sometimes added for the appearance- red, yellow, blue, green.
its really hot over 3000 degrees Celsius. there are flames. its yellow.