1. Chain saw
By Ali Al Thani

2. Introduction
A Chain Saw is a portable mechanical saw powered by electricity or gasoline ; the chain saw is used in activities cutting trees, felling, limbing, Bucking and pruning. Chainsaws have a variety of uses, and depending what someone needs one for will depend on the type of chainsaw that will provide the best option. While most of these motorized saws are used for jobs related to sawing wood, there are also models that have been specially made to cut concrete and others that are specially crafted for use in what is known as chainsaw art.

3. What problem did the chain saw solve
The chain saw solved a lot of problems, it helped cutting trees, the chain saw its automatic you don’t need to use your hands a lot the chain saw has a chain that goes around the saw and it will cut the tree faster. The saw was very long and it was used by two men to cut one tree. Some chain saw are electric and some are used with fuel.
Gasoline Chain Saw Two Man Saw Electric Chain Saw.

4. The inventor
Bernard Heine was born in August 20, 1800,He died in July 31, 1846 (Aged 45] He lived in Germany
He invented the Oesteotome the first chain saw in the world it was small but use full.
The Oesteotome Dr. Bernard Heine.

5. Story of invention
The German Bernard Heine invented the Chain Saw in the But several makings thought the first chain saw was built in the 1920’s but the 1830 Oesteotome predated them all. One Claimed that the Californian inventor named Muir first one to put a blade on chain saw Called “The Logging Chain Saw “. In 1926 A German mechanical engineer Andreas Stihl made a Cutoff chain saw with an electric power. In 1929 Andreas Stihl made a gasoline powered chain saw.

6. How chain saw work
A Chain saw has a spoke that spins and turns the chain along the bar. The chain has a series of small blades that alternate on each side of the chain. The blades run the entire length of the chain. When the chain moves at high speeds it cuts through wood easily.
Every chainsaw has a motor witch runs by gasoline. This two stroke motor moves the chain along the bar, and allows the machine to cut through materials like trees or hard ice.

7. How does chainsaw solve the problem
Chains saws take less time to cut trees or anything else chain saw cuts in a very high speed it has small blades to cut through things.

8. What humans did about the problem before this invention.
Humans was using Axes and saws before the invention of chainsaw. It took with them long time to cut the trees and branches. Those time were really hard and made the workers tired of themselves.

9. How this invention improved human life
This invention helped the workers to Save time
Workers only need to put less energy
They can cut more trees and branches when compared to using axe and saw
Less number of workers is required when compared to old times

10. Detail changes or improvements through out the time
The first saw was used by two people.
This is the gasoline chainsaw.

11. Invention problems
The chain saw caused problems by safety issues and pollution because the smoke comes out of the chainsaw causes pollution.

12. Time line Chain Saw Time Line 1830 First Chain saw
1830 First Chain saw
1861 Handcrancked Chain Saw
1905 Water-cooled chainsaw
1929 gas powered chain saw
1950 One Man Chain saw
1972 Electric ignition Chain Saw
1972 Chain brake/ Auto start.

13. The source list
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