Easier
- A simple
machine is a device that helps make work easier; a
device that makes it easier to move something. Some
simple machines are a wheel, a pulley, a lever, a
screw, and an inclined plane.
Harder
- Most
machines consist of a number of elements, such as
gears and ball bearings, that work together in a
complex way. No matter how complex a machine, it is
still based on the compounding of six types of simple
machines. The six types of machines are the lever, the
wheel and axle, the pulley, the inclined plane, the
wedge, and the screw.
Background
Information for Simple Machines
from
National Museum of Science and Technology
,
Canada
http://www.science-tech.nmstc.ca/english/schoolzone/Info_Simple_Machines.cfm
Here you can find the answers to some commonly
asked questions about simple machines.
The
Elements of Machines: Simple Machines
from
Leonardo"s Workshop
http://www.mos.org/sln/Leonardo/InventorsToolbox.html
Learn about devices that make work easier to do by
providing some tradeoff between the force applied and
the distance over which the force is applied. Also
provides a brief introduction to uses of a gear, cam,
crank and rod, chain and belt, and the ratchet.
Levers
from Beakman & Jax
http://www.beakman.com/lever/lever.html
Play with levers and find out how work from the
fulcrum to the load to the effort.
(Wait for second page to come)
Marvelous
Machines
http://www.galaxy.net:80/~k12/machines/index.shtml
This website provides a series of experiments
about simple machines: levers, wheels and inclined
planes. They were developed for third grade students.
(Comes up slowly
)
| After exploring some or all of the websites below, complete one or more of these activities: Investigate Wheels with Your Bicycle. Go to PBS Teachersource"s website and use your bicycle to learn about the wheel. Find Out How Stuff Works. Check out How Stuff Works . Look for a device that uses a simple machine as part of how it works. Create a poster showing how it works. Gear Up with a Tricycle & Bicycle. Visit PBS Teachersource"s site and follow the procedures there to learn a lot more about gears. Complete a Simple Machines WebQuest. Follow or adapt the procedures found at one of these webQuest sites: 1) Exploring Simple Machines by Paula Markowitz (Grade 4) http://www.lakelandschools.org/EDTECH/Machines/Machines.htm 2) Simple Machines http://www.eng.iastate.edu/twt/Course/packet/labs/wheels&leverLab.htm 3) Simple Machines WebQuest (Grade 4-6) http://www.plainfield.k12.in.us/hschool/webq/webq8/jjquest.htm 4) Simple Machines http://www.beth.k12.pa.us/schools/wwwclass/mcosgrove/simple.htm 5) Simple Machines Webquest http://www.jsd.k12.ak.us/ab/el/simplemachines.html Complete an Online Simple Machines Activity. Learn more about simple machines by following the directions at A Time for Simple Machines . You may also want to test your knowledge at Gadget Anatomy . Complete Some Simple Machine Experiments. Find lots of experiments at sites like Marvelous Machines and Motion, Energy and Simple Machines . |
The wheel and axle , the inclined plane , the wedge , the , and the screw . Several of these simple machines are related to each other. But, each has a specific purpose in the world of doing work.
There are special tools for measuring the force necessary to move an object. These are known as force meters. They use a spring and a hook to determine how much pull is required to slide an object up an inclined plane. Really very simple to use.
Compound Machines
Simple machines can be combined together to form compound machines. Many of our everyday tools and the objects we use are really compound machine . Scissors are a good example. The edge of the blades are wedges. But the blades are combined with a lever to make the two blades come together to cut.
A lawnmower combines wedges (the blades) with a wheel and axle that spins the blades in a circle. But there is even more. The engine probably works in combination of several simple machines and the handle that you use to push the lawnmower around the yard is a form of a lever. So even something complicated can be broken down into the simple st of machines.
Take a look around you — can you figure out what simple machines make up a can opener, the hand cranked pencil sharpener, the ice dispenser in the refrigerator or the stapler? Just be careful, though. In our modern times, many things rely on electronics and light waves to function and are not made of simple machines. But even then, you may be surprised. The turntable in your microwave oven is a wheel and axle. The lid to the laptop is connected to the pad by a hinge or lever.
Simple machines may be simple — but the y are simply everywhere.
A Word or Two About Rube
Rube Goldberg was a famous cartoonist who lived between 1883 and 1970. His life was spent creating art and sculptures, but his most famous work was for his "inventions." These inventions were a series of simple machines put together in a complex fashion to accomplish something very simple, but it took many steps to get there. Contests have been run for many years since Mr. Goldberg first created his unique ideas. In the contests people try to come up with new ways to turn on a light, or start a toaster using these combinations of the simple machines to wow judges and audiences for their unique way of doing these simple tasks.
Rube Goldberg machines are fun to watch and to build. Visit this site for some fun — see if you can identify each of the simple machines as they work together in this animation of a Rube Goldberg gadget designed to get this guy out of bed in the morning. Click .
For more information about Rube Goldberg"s life and his art, click .
A simple machine is a mechanical device that consists of a minimum of moving parts but yet can create an improvement of the output over the input. The improvement could be creating a mechanical advantage or simply changing the direction of the output. Mechanical advantage is the increase of force, distance or speed from the input value.
Around the 16th century, the classic list of simple machines was determined. The list consisted of the lever, wheel and axle, pulley, inclined plane, wedge, and screw.
These simple machines can be broken into three classifications: lever simple machines, rotating simple machines, and inclined plane simple machines.
Questions you may have include:
- What do lever simple machines do?
- What do rotating simple machines do?
- What do inclined plane simple machines do?
This lesson will answer those questions. Useful tool: Units Conversion
Lever simple machines
The lever simply consists of a rod or board that pivots on a fulcrum, creating a mechanical advantage or a change in direction.
The lever is a classic simple machine that achieves a mechanical advantage according to the ratio of the output or load arm of the lever divided by the input or effort arm.
The mechanical advantage of a lever can concern force, distance, or speed of the output.
The efficiency of the lever is very high, since the loss due to friction at the fulcrum is low.
Rotating simple machines
Rotating simple machines include rollers, wheel and axle, crank, and pulley.
Rollers
The wheel or roller by itself can make it easier to move objects by overcoming friction.
Wheel and axle
When an axle is added to a wheel, a torque on the axle increases the speed of the outer surface of the wheel. Likewise, turning the wheel from its outer edge increases the force applied from the axle.
Crank
A crank is like a wheel and axle. You can push on the handle of a crank, and it will create a twisting force or torque on the axle. This is a variation of the wheel and axle.
Pulley
A pulley is a wheel and axle, that uses a rope to lift objects. A major purpose of a pulley is to change the direction of the input force. You can pull down one a pulley rope, and the rope will lift the object upward.
Complex set of pulleys
A complex set up pulleys, such as a block-and-tackle configuration, can result in a mechanical advantage. The question is that if it is a complex set, is it still a simple machine? Probably not.
Inclined plane simple machines
Variations of an inclined plane include a ramp, wedge, and screw.
Ramp
The inclined plane or ramp makes raising a weight to a given height easier, according to the angle of the incline. Unfortunately, the resistive force of friction from sliding the object on the ramp can negate the mechanical advantage.
Variations of the inclined plane are the wedge and screw.
Wedge
Although a wedge is considered a simple machine, it is really a special application of an inclined plane.
Screw
The screw is really an inclined plane that is wrapped around a shaft. Turning the shaft around its central axis transforms rotational motion and torque into axial motion and force.
A screw can also act like a wedge, forcing itself into a softer material.
Summary
Simple machines usually exchange using a smaller force over a greater distance to move a heavy object over a short distance. The work required is the same, but the force required is less. The are also simple machines that help to reduce the resistance of friction or such.
Make it your mission to benefit your community
Topic: Simple Machines PSSA: 3.4.7.C / S8.C.3.1
Objective: TLW compare different types of simple machines. TLW compare different types of simple machines. TLW explain the difference between a simple machine and a compound machine. TLW explain the difference between a simple machine and a compound machine.
MI #1: Levers A lever is a simple machine that has a bar that pivots on a fixed point called a fulcrum. A lever is a simple machine that has a bar that pivots on a fixed point called a fulcrum. Levers are classified based on the location of the input force, load, and the fulcrum. Levers are classified based on the location of the input force, load, and the fulcrum.
MI #2: Classes of Levers First class levers have the fulcrum between the input force and the load. First class levers have the fulcrum between the input force and the load. - Includes see-saws Second class levers have the load between the input force and the fulcrum. Second class levers have the load between the input force and the fulcrum. - Includes wheelbarrows Third class levers have the input force between the load and the fulcrum. Third class levers have the input force between the load and the fulcrum. - Includes hammers and fishing poles
Mi #3: Pulleys A pulley is a simple machine that has a grooved wheel that holds a rope or a chain. A pulley is a simple machine that has a grooved wheel that holds a rope or a chain. There are three types of pulleys; fixed, movable, and block and tackle. There are three types of pulleys; fixed, movable, and block and tackle.
MI #4: Wheel and Axle A wheel and axle consists of two circular objects of different sizes that rotate on the same axis. A wheel and axle consists of two circular objects of different sizes that rotate on the same axis. The axle rotates a smaller distance than the wheel, which results in a greater output force. The axle rotates a smaller distance than the wheel, which results in a greater output force.
MI #5: Inclined Planes An inclined plane is a straight slanted surface. An inclined plane is a straight slanted surface. A wedge is a pair of inclined planes that move. A wedge is a pair of inclined planes that move. A screw is an inclined plane wrapped around a cylinder. A screw is an inclined plane wrapped around a cylinder.
MI #6: Compound Machines A compound machine is a machine that is made of two or more simple machines working together. A compound machine is a machine that is made of two or more simple machines working together. Because compound machines have more moving parts, their mechanical efficiency is typically low. Because compound machines have more moving parts, their mechanical efficiency is typically low.
So What…? Real Life Application Machines make work easier, so it is important to understand the different types of simple machines. Machines make work easier, so it is important to understand the different types of simple machines.
A lever is a simple machine that allows you to gain a mechanical advantage in moving an object or in applying a force to an object. It is considered a "pure" simple machine because friction is usually so small that it is not considered a factor to overcome, as in other simple machines.
A lever consists of a rigid bar or beam that is allowed to rotate or pivot about a fulcrum. An applied force is then used to move a load. There are three common types or classes of levers, depending on where the fulcrum and applied force is located.
The mechanical advantage is that you can move a heavy object using less force than the weight of the object, you can propel an object faster by applying a force at a slower speed, or you can move an object further than the distance you apply to the lever.
Questions you may have include:
- What are the parts of a lever?
- What are the three types or classes of levers?
- What are the uses for a lever?
This lesson will answer those questions. Useful tool: Units Conversion
A typical lever consists of a solid board or rod that can pivot about a point or fulcrum . Since humans usually provide energy to levers, "effort" and "load" are often used instead of input and output.
An input force or effort is applied, resulting in moving or applying an output force to a load .
The distance from the applied force or effort force to the fulcrum is called the effort or input arm and the distance from the load to the fulcrum is called the load or output arm .
Since there is typically a very small amount of friction at the fulcrum, overcoming friction is not a factor in a lever as it might be in another simple machine like a ramp or wedge. Thus, we consider a lever a pure simple machine.
Lever configurations
There are three types or classes of levers, according to where the load and effort are located with respect to the fulcrum.
Class 1
A class 1 lever has the fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. This is the most typical lever configuration.
Class 2
A class 2 lever has the load between the effort and the fulcrum. In this type of lever, the movement of the load is in the same direction as that of the effort. Note that the length of the effort arm goes all the way to the fulcrum and is always greater than the length of the load arm in a class 2 lever.
Class 3
A class 3 lever has the effort between the load and the fulcrum. Both the effort and load are in the same direction. Because of the configuration, the fulcrum must prevent the lever beam from moving upward or downward. Often a bearing is used to allow the beam to pivot.
Note that the length of the load arm goes all the way to the fulcrum and is always greater than the length of the effort arm in a class 3 lever. The result is a force mechanical advantage less than 1.
Uses for a lever
The reason for a lever is that you can use it for a mechanical advantage in lifting heavy loads, moving things a greater distance or increasing the speed of an object.
Increase force
Increase distance moved
You can increase the applied force in order to lift heavier loads.
Increase speed
You can increase the speed that the load moves with Class 1 or Class 3 levers.
Summary
A lever is a simple machine that allows you to gain a mechanical advantage. It consists of a consists of a rigid bar or beam that is allowed to rotate or pivot about a fulcrum, along with an applied force and load. The three types or classes of levers, depend on where the fulcrum and applied force is located.
Uses for a lever are that you can move a heavy object using less force than the weight of the object, propel an object faster by applying a force at a slower speed, or move an object further than the distance you apply to the lever.
Leveraging gives you an advantage
