The stratosphere (/ËstrÃ¦tÉËsfÉªÉr, -toÊ-/) is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. About 20% of the atmosphere's mass is contained in the stratosphere.
The chainsaw is a highly effective and efficient tree and branch cutting power tool. It works with an engine, referred to as a power head; powering a metal chain, driven by a centrifugal clutch, with a chain moving around a groove in the guide bar at fast speeds.
Chainsaws cut in a curve (walk) if their chains are dull. The user applies more force to compensate for the dull chain, and usually applies uneven force because both hands are on the same side of the cutting bar. They can also walk if one side of the chain has been damage by contact with stone or metal.