We use the term 'atmosphere' quite often, but what does it mean? There are four important spheres of the earth - the atmosphere, hydrosphere, biosphere, and lithosphere. Atmosphere concerns the air, and is the term used for the envelope of air which surrounds the earth. This envelope of air is divided into several layers based on various factors like composition, temperature, etc., The five distinct layers of the atmosphere are - the troposphere, stratosphere, mesosphere, thermosphere and exosphere, in order from the ground surface. It is interesting to note that the atmospheric layers stretch to some 600 kilometers above the ground level! The density of air in the atmospheric layers lowers as we move up and then it is the highest at the first two layers, the troposphere and the stratosphere. Our point of discussion in this article is the second layer of the atmospheric layers. It is an important layer of the earth's atmosphere, because it also incorporates the very important ozone layer, the significance of which needs no mention. Interesting Stratosphere Facts ✔ It occupies the central region of the atmosphere, and is the second layer of the atmosphere from the ground surface; tropopause separates stratosphere from the troposphere. ✔ The layer constitutes about 24% of the total atmosphere. And it contains about 19% of the atmospheric gases. ✔ It extends to some 50 km above the ground level. ✔ Ozone layer forms the upper crust of the stratosphere, and has about 90% of ozone layer. This layer combines oxygen atoms to form the ozone molecules. Ozone molecules absorb the harmful UV radiations from the sun. ✔ The temperature rises as we move upwards in this zone. Reason for this increase in temperature is absorption of harmful ultraviolet rays of the sun by the ozone molecules. ✔ There is no uniformity in the stratosphere if the temperature is considered. This is because of the presence of ozone layer at the top region. The temperature at the top of stratosphere is around 270 K (-3°C or 29.6°F). The temperature in the middle and lower region is less as the UV rays do not reach there. ✔ Composition of gases: Atomic oxygen (O) is found in the upper region. UV rays break the ozone (O₃) molecule into atomic oxygen and diatomic oxygen (O₂). Along with these gases, methane is also found in the upper region of the atmospheric layer. Methane (CH₄) reacts with many hydroxy compounds (-OH) and can destroy the ozone molecules. The water vapor proportion in this layer is very low. Fun Facts for Kids ✔ This is the second layer of the atmosphere from the surface of the earth, and lies between the troposphere and the mesosphere. ✔ In stratosphere - 'strato' means layer and sphere is the shape of the earth. Thus it means layer which surrounds the earth. ✔ There are no clouds in the layer, and though there are wind currents in this sphere, it is a relatively calmer layer. ✔ The crucial ozone layer, which protects us from the harmful UV rays of the sun, is a part of this atmospheric layer, and forms a thin layer at the upper region of this sphere. ✔ Spy jets fly in the lower layer as the weather conditions there are conducive to flying. In bad weather conditions, or when the fuel is running out, airplanes move up from the troposphere to this layer because the air density is low, and the planes can fly at top speeds without encountering any turbulence. ✔ Life exists in the stratosphere in the form of some biological bacteria, making it a part of the biosphere too! ✔ Some birds also reach the heights of stratosphere (in the lower part though) and can fly there. This layer incorporates the ozone layer and to protect the ozone layer we need to increase the oxygen and decrease the CFCs in the air. Thus planting trees is a solution each one of us can follow, to protect our earth from the harmful effects of ozone depletion.