Throughout history, humans have developed several devices to make work easier. Progetto asi/99/17- responsabile prof most notable of these are known as the " six simple machines ": the wheel and axle, the lever, the inclined plane, the pulley, the screw, and the wedge, although the latter three are actually just extensions or combinations of the first three. Because work is defined as force acting on an object in the direction of motion, a machine makes work easier to perform by accomplishing one or more of the following functions, according to Jefferson Lab :.
Simple machines are devices with no, or very few, moving parts that make work easier.Rube Goldberg easy examples
Many of today's complex tools are just combinations or more complicated forms of the six simple machines, according to the University of Colorado at Boulder. For instance, we might attach a long handle to a shaft to make a windlass, or use a block and tackle to pull a load up a ramp. While these machines may seem simple, they continue to provide us with the means to do many things that we could never do without them. The wheel is considered to be one of the most significant inventions in the history of the world.
The wheel greatly reduces the friction encountered when an object is moved over a surface. In his book "Ancient Science: Prehistory-A. As the object moved forward, rollers were taken from behind and replaced in front. The great innovation, though, was in mounting a wheel on an axle.
The wheel could be attached to an axle that was supported by a bearing, or it could be made to turn freely about the axle. This led to the development of carts, wagons and chariots. According to Samuels, archaeologists use the development of a wheel that rotates on an axle as an indicator of a relatively advanced civilization. The earliest evidence of wheels on axles is from about B. The Chinese independently invented the wheel in B. In addition to reducing friction, a wheel and axle can also serve as a force multiplier, according to Science Quest from Wiley.
If a wheel is attached to an axle, and a force is used to turn the wheel, the rotational force, or torque, on the axle is much greater than the force applied to the rim of the wheel. Alternatively, a long handle can be attached to the axle to achieve a similar effect.
Kolodner and her co-authors write, "Machines provide mechanical advantage to assist in moving objects. Mechanical advantage is the trade-off between force and distance. When a force is applied over a distance, it produces work. For example, to lift an object, we must do work to overcome the force due to gravity and move the object upward.
Three Simple Machine Projects for Kids: Fabulous & Fun to Make
To lift an object that is twice as heavy, it takes twice as much work to lift it the same distance. It also takes twice as much work to lift the same object twice as far. As indicated by the math, the main benefit of machines is that they allow us to do the same amount of work by applying a smaller amount of force over a greater distance.
While it may be a bit of an exaggeration, it does express the power of leverage, which, at least figuratively, moves the world.Common examples of simple machines include the hammer, crowbar, knife, log splitter, scissors, light switch, door knob, escalator, ladder, screwdriver, ramp, stairs, car jack, curtain cord and steering wheel. The six types of simple machines include the wheel and axle, inclined plane, simple lever, pulley, wedge and screw.
The wheel and axle, simple lever and pulley constitute the lever family, while the inclined plane, wedge and screw are part of the inclined plane family. A machine is an electrical or mechanical contraption that lightens a workload.
It utilizes energy to alter the direction, increase the rate, transfer or multiply the force required to carry out a particular task. There are two types of mechanical machines: simple and compound. A simple machine is composed of only one mechanical apparatus, while a compound machine comprises two or more simple machines. Simple machines provide a mechanical advantage, which is the factor by which a machine increases the magnitude of a force.
The work output refers to the amount of work done by a machine, while the work input pertains to the amount of work exerted into the machine. The lever family exerts a rotational force that changes the direction of the work output from the work input. The inclined plane family alters the direction of work output at an angle of 90 degrees to the direction of the work input.
Home Science.A machine is a tool used to make work easier. It can do so by changing the direction of a force, increasing the distance or speed of a force, transferring a force from one place to another or increasing the magnitude of a force. Machines are everywhere in our daily lives and make peoples' lives today much simpler, but no matter how complex a machine may appear, it is simply a combination of the six simple machines.
An inclined plane is simply an even, sloping surface. One common example of an inclined plane is a ramp. Lifting heavy items onto a higher surface is much easier if you just slide the item up a ramp. A wedge is a modification of an inclined plane. Wedges are usually used as either separating or holding devices. An axe blade is one example of a wedge — you can make a small crack much larger by using an axe blade.
Another example is a door stop. A screw is another modified inclined wedge. This can be hard to visualize, but just think of a screw as an inclined plane wrapped around a cylinder. Any tool that is used to help pry something loose is a lever. A lever is an arm that pivots against a fulcrum. An example is the claw end of a hammer, being used to pry nails out of wood. Another example is a seesaw.
A wheel and axle consist of a large wheel secured to a smaller shaft, here referred to as an axle. If the wheel turns but the axle remains stationary, it isn't a true wheel-and-axle machine. Wheels and axles are everywhere — think of a childhood play wagon for one example of a wheel and axle in motion.
A pulley is a machine similar to a wheel and axle, but where rope is turned rather than the axle. As the wheel rotates, the cord is moved in either direction. This can help lift or move objects. A flagpole is one example of a pulley. As a machine, a pair of scissors seems pretty simple, though it's actually a complex machine. A scissors combines two levers with the cutting action of the wedge.
The levers multiply the force on the object to be cut, making it easier to use and more effective than a knife. Like the scissors, a two-wheeled hand truck is also a complex machine. The lever and the wheel and axle partner to make a machine that lets you lift and move furniture, appliances and other objects too awkward or heavy to carry by hand.
It should be no surprise that an automobile with a gasoline engine is a complex machine, made of thousands of simple machines. Inside the engine, each rocker arm that operates the many valves is a lever.Work is performed by applying a force over a distance.
Simple Machines Examples
These six simple machines create a greater output force than the input force; the ratio of these forces is the mechanical advantage of the machine. All six of the simple machines listed here have been used for thousands of years, and the physics behind several of them were quantified by the Greek philosopher Archimedes ca.
When combined, these machines can be used together to create an even greater mechanical advantage, as in the case of a bicycle. A lever is a simple machine that consists of a rigid object often a bar of some kind and a fulcrum or pivot.
Applying a force to one end of the rigid object causes it to pivot about the fulcrum, causing a magnification of the force at another point along the rigid object. There are three classes of levers, depending on where the input force, output force, and fulcrum are in relation to each other.
The earliest lever was in use as a balance scale by BCE; Archimedes is credited with saying "Give me a place to stand and I will move the earth. A wheel is a circular device that is attached to a rigid bar in its center.
A force applied to the wheel causes the axle to rotate, which can be used to magnify the force by, for example, having a rope wind around the axle. Alternately, a force applied to provide rotation on the axle translates into rotation of the wheel. It can be viewed as a type of lever that rotates around a center fulcrum. The earliest wheel and axle combination known was a toy model of a four-wheeled cart made in Mesopotamia about BCE.
Ferris wheelstires, and rolling pins are examples of wheels and axles. An inclined plane is a plane surface set at an angle to another surface. This results in doing the same amount of work by applying the force over a longer distance. The most basic inclined plane is a ramp; it requires less force to move up a ramp to a higher elevation than to climb to that height vertically. Archimedes's "On Plane Equilibrium" describes the centers of gravity for various geometrical plane figures.
The wedge is often considered a double inclined plane—both sides are inclined—that moves to exert a force along the lengths of the sides. The force is perpendicular to the inclined surfaces, so it pushes two objects or portions of a single object apart. Axes, knives, and chisels are all wedges. The common "door wedge" uses the force on the surfaces to provide friction, rather than separate things, but it's still fundamentally a wedge.
The wedge is the oldest simple machine, made by our ancestors Homo erectus at least as long ago as 1. A screw is a shaft that has an inclined groove along its surface. By rotating the screw applying a torquethe force is applied perpendicular to the groove, thus translating a rotational force into a linear one.
It is frequently used to fasten objects together as the hardware screw and bolt does. The Babylonians in Mesopotamia developed the screw in the 7th century BCE, to elevate water from a low-lying body to a higher one irrigate a garden from a river.
This machine would later to be known as Archimedes' screw. A pulley is a wheel with a groove along its edge, where a rope or cable can be placed. It uses the principle of applying force over a longer distance, and also the tension in the rope or cable, to reduce the magnitude of the necessary force. Complex systems of pulleys can be used to greatly reduce the force that must be applied initially to move an object.
Simple pulleys were used by the Babylonians in the 7th century BCE; the first complex one with several wheels was invented by the Greeks about BCE.
Archimedes perfected the existing technology, making the first fully-realized block and tackle. The first use of the word "machine" "machina" in Greek was by the ancient Greek poet Homer in the 8th century BCE, who used it to refer to political manipulation.
The Greek playwright Aeschylus — BCE is credited with using the word in reference to theatrical machines such as the " deus ex machina " or "god from a machine.Last year we learned about simple machines with a really fun, hands on 5 week Simple Machines Unit. It was so much fun that we wanted to follow up our study with some review activities. With over 30 creative, fun, and unique ideas for teaching simple machines for kids you are bound to find the perfect project for your target audience.
These are fun activiteis for kids in social isolation as you can make simple machines around the house. Your hardest choice is which one of these science projects to try first! Learn how to make a lava lamplearn about capillary action with this amazing walking water experimentor help kids visualize density with this balloon science expeirment. Looking for more fun, creative ways you can begin homeschooling for free? We have over 1, pages of FREE pre k worksheetskindergarten worksheetsgrade 1 worksheetssecond grade worksheets and more for K As a busy homeschooling mother of six, she strives to create hands-on learning activities and worksheets that kids will love to make learning FUN!
Beth is also the creator of 2 additional sites with even more educational activites and FREE printables: www. Recipe Rating. You may also like. View all posts.Simple machines are the most basic machines. They make work easier by altering force. These easy-to-build simple machine projects explore a pulley, inclined plane, and a lever using common household objects. An inclined plane is a flat surface with one raised end used to lessen the force needed to raise objects.
Is it easier for Barbie to climb straight up the book mountain or use the ramp? Tie a string around Barbie and attach the rubber band to the string. Stack the books in a pile to make the 'mountain'. Lift Barbie by pulling the rubber band straight up to the top of the book pile. Measure the length of the rubber band as you are pulling Barbie up the side of the mountain and record your results. Use the board and book pile to make a ramp inclined plane.
Pull Barbie up the ramp with the rubber band. Measure the length of the rubber band as she is pulled up the ramp and record your results. Which was the easiest way to move Barbie to the top of the pile? A pulley changes the direction of a force needed to do work. Can you use a pulley to send a snack to a hungry friend across the room? Tie the ends of the string together to make a large loop. Put the pencils through the spool centers. Hold one pencil so the spool moves freely.
Have a friend stand on the other side of the room with second spool. Wrap the string around the spools. Attach the snack to the string with a paper clip or binder clip. Pull the string to move the chips. Did the chips move across the room? What did you think would happen? What could you change? What did you learn? A lever can change the size and direction of a force. Where should you push on a lever to get the best lift?
What happens if you change the size of the fulcrum? Place the pencil under the popsicle stick to make a lever. Place a bean on one end of the lever. Drop the other coin from a height of 30 cm.
Notice how high the bean jumps. Repeat but drop the coin so it lands halfway between the end of the stick and the pencil.
How high did the other bean jump?Simple machineany of several devices with few or no moving parts that are used to modify motion and force in order to perform work. The simple machines are the inclined plane, lever, wedge, wheel and axle, pulleyand screw.
An inclined plane consists of a sloping surface; it is used for raising heavy bodies. The plane offers a mechanical advantage in that the force required to move an object up the incline is less than the weight being raised discounting friction.
The steeper the slope, or incline, the more nearly the required force approaches the actual weight. The principle of the inclined plane is used widely—for example, in ramps and switchback roads, where a small force acting for a distance along a slope can do a large amount of work. A lever is a bar or board that rests on a support called a fulcrum. A downward force exerted on one end of the lever can be transferred and increased in an upward direction at the other end, allowing a small force to lift a heavy weight.
All early people used the lever in some form, for example, for moving heavy stones or as digging sticks for land cultivation. The principle of the lever was used in the swape, or shadoofa long lever pivoted near one end with a platform or water container hanging from the short arm and counterweights attached to the long arm.
A man could lift several times his own weight by pulling down on the long arm. This device is said to have been used in Egypt and India for raising water and lifting soldiers over battlements as early as bce. A wedge is an object that tapers to a thin edge.
Pushing the wedge in one direction creates a force in a sideways direction. It is usually made of metal or wood and is used for splitting, lifting, or tightening, as in securing a hammer head onto its handle. The wedge was used in prehistoric times to split logs and rocks; an ax is also a wedge, as are the teeth on a saw.
In terms of its mechanical function, the screw may be thought of as a wedge wrapped around a cylinder. A wheel and axle is made up of a circular frame the wheel that revolves on a shaft or rod the axle. In its earliest form it was probably used for raising weights or water buckets from wells. Its principle of operation is best explained by way of a device with a large gear and a small gear attached to the same shaft.
The tendency of a force, Fapplied at the radius R on the large gear to turn the shaft is sufficient to overcome the larger force W at the radius r on the small gear. The force amplification, or mechanical advantageis equal to the ratio of the two forces W : F and also equal to the ratio of the radii of the two gears R : r. If the large and small gears are replaced with large- and small-diameter drums that are wrapped with ropes, the wheel and axle becomes capable of raising weights. The weight being lifted is attached to the rope on the small drum, and the operator pulls the rope on the large drum.
In this arrangement the mechanical advantage is the radius of the large drum divided by the radius of the small drum. An increase in the mechanical advantage can be obtained by using a small drum with two radii, r 1 and r 2and a pulley block. When a force is applied to the large drum, the rope on the small drum winds onto D and off of d. A measure of the force amplification available with the pulley-and-rope system is the velocity ratio, or the ratio of the velocity at which the force is applied to the rope V F to the velocity at which the weight is raised V W.
This ratio is equal to twice the radius of the large drum divided by the difference in the radii of the smaller drums D and d.
A very large mechanical advantage may be obtained with this arrangement by making the two smaller drums D and d of nearly equal radius. Simple machine. Article Media. Info Print Print. Table Of Contents. Submit Feedback.