By Hassaan QaziFA05-BF-0006

AGENDAEvaporation processAcid rainsOzone layerConclusion

EVAPORATIONEvaporation is the process by

which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapor)

without being heated to boiling point.

It is the opposite of condensationGenerally, evaporation can be

seen by the gradual disappearance of a liquid, when exposed to sunlight.

WATER CYCLE

ACIDS RAINSThe term acid rain or more accurately acid

precipitation is commonly used to mean the deposition of acidic components in

1.Rain2.Snow3.Dew4.Dry particles

CAUSES OF ACID RAINSAcid rain occurs when

sulfur dioxide and nitrogen oxides are emitted into the atmosphere.

Undergo chemical transformations, and are absorbed by water droplets in clouds.

The droplets then fall to earth as rain, snow, mist, fog etc.

OZONE LAYEROzone (O3) is a tri-atomic

molecule consisting of three oxygen atoms.

Its Systematic name Trioxygen.

It’s a bluish colored gas.Situated about 15 to 30 km

away from the earth.

OZONE LAYERProtects living beings by

absorbing harmful ultraviolet radiation (UVB) from the sun.

DESTRUCTION OF LAYERCFCs are responsible

for the destruction of the ozone layer.

If the ozone layer is completely destroyed then harmful UV radiation.

CONCLUSIONFirstly we must try to reduce the emission of

sulfur dioxide and nitrogen oxides to prevent acid rains.

Secondly to reduce the use of CFCs related products in order to save the depletion of ozone layer.