Simple Machine

Bernadeta Tan GaleaSto.Rosario Elementary School

Pateros District

Simple Machine• A machine is a tool used to make work easier. Simple machines

are simple tools used to make work easier. Compound machines have two or more simple machines working together to make work easier.

• In science, work is defined as a force acting on an object to move it across a distance. Pushing, pulling, and lifting are common forms of work. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see-saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help break through the weeds. The children use a see-saw to go up and down. The ramp, the shovel, and the see-saw are simple machines.

Inclined Plane • A plane is a flat surface. For example, a smooth board is a plane. Now, if the plane is lying flat on the ground, it isn't likely to help you do work. However, when that plane is inclined, or slanted, it can help you move objects across distances. And, that's work! A common inclined plane is a ramp. Lifting a heavy box onto a loading dock is much easier if you slide the box up a ramp--a simple machine.

The force moves in the same direction as the load. Notice that in the picture, the force pushes in the same direction that the skateboard is moving.

Example: Door Knob, Wagon, Toy Car

Inclined Plane

• What is it? An inclined plane is a flat, sloping surface.

• Why do we use it?Inclined planes are used to make the job of moving heavy objects easier. An object can go up an inclined plane or down.

Objects ususally move straight up and down. This takes the most work and is harder if objects are heavy. With an inclined plane, the slope makes it easier to push or pull the object.

Incline Plane• Fun facts:• Remember our Egyptian Unit?

Egyptians used inclined planes to make their pyramids and reach high areas.

Examples of Inclined Planes

Rampa ramp is used to push up an object or roll it down.

Wedge • Instead of using the smooth side of the inclined plane, you can also use the pointed edges to do other kinds of work. For example, you can use the edge to push things apart. Then, the inclined plane is a wedge. So, a wedge is actually a kind of inclined plane. An axeblade is a wedge. Think of the edge of the blade. It's the edge of a smooth slanted surface

Wedge• What is it?

A wedge is a simple machine made up fo two inclined planes put together. These 2 planes meet and form a sharp edge.

• Why do we use it?Wedges are used to push two objects apart, or cut an object into pieces. It can also hold objects in place.

• A wedge gets in between objects and splits it apart.• An object like wood, can be split apart with a wedge.

Fun facts:• You probably use a

wedge everyday. A fork is considered a wedge. It is made up for 4 to 5 wedges put together. It can be used to cut or split food apart.

wedge

• Doorstopa doorstop is used to hold doors in place. The doorstop is a wedge that goes between the door and the floor.

KnifeA knife is a wedge with a sharpened edge that can cut objects into pieces

Screw • Now, take an inclined plane and wrap it around a cylinder. Its sharp edge becomes another simple tool: the screw. Put a metal screw beside a ramp and it's kind of hard to see the similarities, but the screw is actually just another kind of inclined plane.

• How does the screw help you do work?

• Every turn of a metal screw helps you move a piece of metal through a wooden space. And, that's how we build things! Want to know more?

This simple demonstration shows how a screw is actually an inclined plane. You may want to do this as a demonstration for your class or have every student make their own.MaterialsPencilPaperColored felt tip markerScissors

Procedure1. Cut a right triangle from the paper. The dimensions should be about 5 inches, by 9 inches, by 10.3 inches.2. Use the felt tip marker to color the longest edge (10.3 inches) of the triangle.3. Position the shortest side (5 inches) of the triangle along the side of the pencil and then evenly wrap the paper around the pencil by rolling the pencil.

The Screw

Screw

• Try pulling a really stubborn weed out of the ground. You know, a deep, persistent weed that seems to have taken over your flowerbed. Using just your bare hands, it might be difficult or even painful. With a tool, like a hand shovel, however, you should win the battle. Any tool that pries something loose is a lever. A lever is an arm that "pivots" (or turns) against a "fulcrum" (or point). Think of the claw end of a hammer that you use to pry nails loose. It's a lever. It's a curved arm that rests against a point on a surface. As you rotate the curved arm, it pries the nail loose from the surface. And that's hard work!

leverSystem consisting of a bar pivoting on a fulcrum to lift a load. The amount of

effort required is related to the position of the pivot and the length of the bar.

bar    Rigid moving bar around the fulcrum on which an effort is exerted to lift the load.

load    Weight whose inertia exerts a force opposite to the effort exerted on the bar.

effort    Force exerted on the lever bar in order to shift the load.

pivot    Part providing an efficient fulcrum for the lever.

fulcrum    Point around which the lever pivots.

Lever

Item Number of Class 1 Levers Used

see-saw a single class 1 lever

hammer's claws a single class 1 lever

scissors 2 class 1 levers

pliers 2 class 1 levers

Number of Class 2 Levers Used

stapler a single class 2 lever

bottle opener a single class 2 lever

wheelbarrow a single class 2 lever

nail clippers Two class 2 levers

nut cracker Two class 2 levers

Item Number of Class 3 Levers Used

fishing rod a single class 3 lever

tweezers Two class 3 levers

tongs Two class 3 levers

Identify the kind of Lever

Wheel and Axle • The rotation of the lever against a point pries objects loose. That rotation motion can also do other kinds of work. Another kind of lever, the wheel and axle, moves objects across distances. The wheel, the round end, turns the axle, the cylindrical post, causing movement. On a wagon, for example, the bucket rests on top of the axle. As the wheel rotates the axle, the wagon moves. Now, place your pet dog in the bucket, and you can easily move him around the yard. On a truck, for example, the cargo hold rests on top of several axles. As the wheels rotate the axles, the truck moves.

A wheel and axle has a larger wheel (or wheels)

connected by a smaller cylinder (axle).

It is fastened to the wheel so that they turn together.

Wheel and axleWheel and axle to reel in the fishing line.

Wheelchairs

The steering wheel is a wheel and the axle goes into the steering column.

Door Knob

Pulley • Instead of an axle, the wheel could also rotate a rope or cord. This variation of the wheel and axle is the pulley. In a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction. Now, attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects. On a flagpole, for example, a rope is attached to a pulley. On the rope, there are usually two hooks. The cord rotates around the pulley and lowers the hooks where you can attach the flag. Then, rotate the cord and the flag raises high on the pole.

double pulley systemSystem consisting of two pulleys with a rope running around them to lift a

load. Using two or more pulleys reduces the amount of effort needed.

load    Weight whose inertia exerts a force opposite to the force exerted on the rope.

pulley    Device with a grooved wheel (sheave wheel) around which a rope passes to transmit the effort exerted on the load.

rope    Cord that slides on the pulley and is pulled to lift the load. effort    Force exerted on the pulley’s rope to lift the load.

Across

1. Bar on which a wheel turns.

4. Cylinder with a ridge winding around it. It's a simple machine.

6. Strength or force that can be exerted on other bodies.

7. An instrument of work.

9. Something that produces action, a moving force.

11. plane A plank or plane surface put at an angle to a horizontal surface.

12. To move, usually with force or effort.

14. Any device that applies or changes the direction of power force, or motion.

Down2. A bar which rests on a fulcrum.3. To move something away by pressing against it.5. A round frame that turns on a pin or shaft in its middle.7. A force that causes rotation.8. Exerting pressure or influence over object or substance.10. The act of a surface or an object rubbing against each other.13. Amount of work a machine is expected to perform.