33rdrd Grade Grade

Ms. LewkoMs. Lewko

*Objectives*

• You will be able to identify each simple machine.

• You will understand the following terms: force, effort, and work.

• You will be able to show your knowledge of simple machines by drawing, demonstrating, and creating a simple machine after we go through this lesson!

Definitions!!!

WORK

WORK: "Work" is only done when something is moved. To measure the amount of work you do, multiply the force times the distance the object moved.

Work= F x D (work= force x distance the object moved)

Force (or weight) is measured in Newton'sDistance is measured in meters.

Unit measure of work = Newton x meter or Newton meterA Newton meter is called a joule

ActivityHow much work is done when an object is lifted?

• MATERIALS: • meter stick

Newton spring scaleobjects to liftstring pencil and paper

Make a chart to record your data. Attach an object to the spring scale.

Slowly lift or pull the object. Record how much force you used to pull or lift the object (Newtons). Measure the distance you moved the object. Record the distance in meters. Find out how much work you did by using the formula, work=force x distance the object moved. Record your answer on the chart. Repeat steps 2-5 with other objects.

FORCE : You are doing work when you use a force to cause motion. Machines make work easier, but they need energy to do work.

A person is usually the source of energy for a simple machine.

A person uses a force to operate a simple machine.

A force is a push or pull. The force applied to the machine is called work.work.

More Vocabulary

Load- The item to be lifted by the lever

Fulcrum- What the lever rests on, or “rocks” on when working.

The point on which the lever moves is called the fulcrum.

*Levers**Levers*

• Levers are probably the most common simple machine

• By changing the position of the fulcrum, you can gain extra power with less effort.

• A good example of a lever is a see-saw.

Can you think of any other examples

Three types of levers

Animated Levers

                                                                                                    

            FIRST CLASS LEVER The fulcrum is between the load and the effort ex: a teeter totter

SECOND CLASS LEVER The load is between the effort and the fulcrum. ex: a wheel barrow

THIRD CLASS LEVER The effort is between the fulcrum and the load.ex: tweezers, your arm

Inclined PlaneInclined Plane

• An inclined plane is a slanted surface used to raise an object.

• A ramp is an inclined plane.

• When an object is moved up an inclined plane, less effort is needed than if you were to lift it straight up, but, you must move the object over a greater distance.

Wheel and AxleWheel and Axle

• A lever that rotates in a circle around a center point or fulcrum. The larger wheel (or outside) rotates around the smaller wheel (axle).

• Bicycle wheels, Ferris wheels and gears are all examples of a wheel and axle

Th

e S

crew

A screw is an inclined plane wrapped around a cylinder, which holds things together or lifts materials.

Examples: jar lids, light bulbs, stools, clamps, key ring

WedgeWedge• A wedge is a simple machine used to push 2 objects

apart.• A wedge is made up of 2 inclined planes. These planes

meet and form a sharp edge that can split things apart. • This changes the direction of the applied force.

Pulley

• A single pulley changes the direction of the lifting force.

• For example, if you are lifting a heavy object with a single pulley anchored to the ceiling, you can pull down on the rope to lift the object instead of pushing up

Can you name any pulleys that are in your home?

Project

• Pick your favorite simple machine

• Then using objects from home create your own simple machine.

• You have 2 weeks to do this.

*If you need any help, you can always ask me!*

• Simple MachinesSimple Machines

 simple machines - a machine with a few parts which you can use to do work in a way that is easier or more effective

 effort - the force needed to operate a simple machine  force - a push or pull used to lift something, start it moving, or hold it in place against another force such as gravity  work - to apply a force that makes an object move (distance an object moves times the force moving it)  energy - the ability to do work or to cause changes in matter  fulcrum - the support that acts as a pivot, allowing a lever to change the

direction of a force  joule - (J) the unit of measurement for energy or work   

SummarySummary