Simple machines
The screw of Archimedes
Archimedes of Syracuse was an inventor scientist who lived in ancient Greece. Among his most important creations we can mention the screw, a very useful machine that was used to raise the water: one of its ends was submerged in the liquid, and when turning the crank, the water was rising through the inside of the tube and flowed through it. the top
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What is a machine?
To perform a job, the man can make use of the strength of his muscles or use a machine, that is, an instrument that allows performing a job with the least possible effort.
Although they seem so different from each other, a car, a bicycle, a screw and a lever are machines, because they have the ability to take advantage of a certain type of energy and modify it, transmit it or use it to perform a job.
In every machine there are three elements:
The driving force or power: is the force applied to operate the device.
The strength of resistance: it is the force that opposes and must be defeated by the power.
The point of support: it is an instrument around which the motive force and resistance force rotate.
The machines that have a single point of support are called simple machines.
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Ramps or inclined planes
Huge constructions have been carried out throughout the history of mankind, for which great weights had to be moved and raised. To achieve this, successive methods were devised until reaching the modern cranes. But there is a simple machine that allows you to do this job with great effort savings: the ramp or inclined plane. It is a flat surface that forms an angle with the floor. The most common is the ramp that serves to raise bodies that move on it.
The use of this resource allows a single person to carry more weight even if they have to travel a greater distance.
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The pyramids of Egypt, for example, are monumental constructions in which huge blocks of stones were used, which were raised by means of ramps.
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Ramps in the city
In daily life, the presence of ramps is constant: inclined roads to climb a mountain; mechanical conveyor belts in shopping centers to lift carts with merchandise; slides to raise and lower the furniture in the removal trucks, et cetera.
In some cities, sidewalks form ramps at the corners to facilitate the movement of people with disabilities who need to move in wheelchairs, or people who carry carts for babies.
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The screws
A screw is also an inclined plane, but it is screwed around a cylinder. This feature allows you to advance with more force than the one that exerts the hand when making it turn.
The screws have a groove in their head on which a tool (screwdriver) can be inserted to give it a rotating movement. There are different types of slots; the most common are flat and star. The latter has the advantage of preventing the screwdriver from running or escaping when screwing or unscrewing.
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Screws and bolts
Basically, the screws and the bolts are operated and work in a similar way, they differ in that:
- The screws have a pointed end to penetrate different materials, such as wood or metal.
- The bolts end in a flat tip, so they do not pierce the material. In addition, they must be fastened with nuts.
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A joining technique
Screwing is a technique used to join two objects. For this, the screwdriver is used, an elongated tool that consists of a handle made of wood, metal or plastic, and a metal piece that ends in a flattened or star-shaped end.
To screw, turn clockwise with the tool so that the screw penetrates the material. To remove a screw, that is, to unscrew, proceed in the same way, but turn counterclockwise.
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