Page 75 - Science Class 08
P. 75
If you carefully observe the flame of the produced by the mel ng of wax. Since, air
candle, you will no ce different colour zones in does not enter this area, gases do not come
the flame. These different zones have different in contact with oxygen and hence this zone
temperatures. is called the dark zone.
On the basis of different colours and heat zones, v Blue Zone : The small region at the base of
we can divide the flame into the following the wick is called the blue zone. In this zone,
zones: carbon monoxide burns with blue colour.
Non-Luminous Zone THE EFFECT OF BURNING OF FUELS ON
The region of complete combus on. ENVIRONMENT
Luminous Zone In previous chapter, you have studied about
The region of incomplete combus on. different types of fossil fuels like coal, petroleum
Dark Zone and natural gas. In this chapter, you studied
The region of no combus on. about the process of combus on. Now, you
Blue Zone know that the combus on of fuels gives us heat
and light energy which we can use for various
The region of carbon monoxide.
purposes. Nowadays, the consump on of fuels
Non-luminous Zone has risen unexpectedly. Do you know, the
burning of these fossil fuels have a great harmful
Luminous Zone effect on our environment? The harmful effect
caused to the environment ul mately cause
Dark Zone
harm to our health and other living beings and
Blue Zone
monuments.
Let’s see how:
Pollu on
Different Zones
It is the most harmful effect of burning of fuels.
v Non-luminous Zone : In this zone of the Fossil fuels like wood, coal and petroleum
flame, complete combus on takes place release many harmful gases like carbon dioxide,
and it is the ho est part of the candle carbon monoxide, lead oxide, nitrogenous
flame. Since this part gets sufficient supply oxides, etc. and unburnt carbon par cles are
of oxygen, all the atoms of carbon, also released. These five par cles are dange-
hydrogen and carbon monoxide are fully rous pollutants that may cause respiratory
diseases like asthma. Harmful gases also cause
oxidised.
various respiratory diseases.
v Luminous Zone : This is the area of
Global Warming
incomplete combus on. Due to inadequate
The rise in average temperature of the atmos-
supply of oxygen, this zone burns incomp-
phere of the earth is referred to as global
letely and the carbon par cles glow with
warming. Due to excessive consump on of
yellow light.
fossil fuels, the amount of carbon dioxide has
v Dark Zone : In this zone, no combus on increased in the atmosphere which has resulted
takes place. It converts the area surrou- in global warming.
nding the wick containing unburnt vapours Global warming has caused the mel ng of polar
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