What do all these pictures have in common?. They make life easier!

What do all these pictures have in common?

They make life easier!

Their devices for doing work.

They make things possible that weren’t

possible before.

They’re Machines!!!!!

Some are simple.Simple Machines:

1. Lever 2. Wheel an Axle 3.Pulley Pulley

4. Inclined Plane 5.Wedge 6. Screw

Simple Machines: The wedge, lever, pulley, wheel and axel, inclined plane, and

screw.• Have been around for thousands of years.• The wedge, inclined plane, and lever are the

oldest known machines.• Stone edge people used wedges to split wood.• Early farmers used wedges as plows to till soil.• Ancient Egyptians used wedges as chisels to

cut massive stone when building pyramids.• They dragged the stones up inclined planes

and moved them into position with levers.

Simple machines continued:

• The Romans moved building stones with cranes that were operated with pulleys.•The effort needed to do the work was provided by slaves walking inside a wheel –shaped treadmill.• In the 3rd century B.C.E., the Greek mathematician Archimedes used the screw to lift water from a lower level to a higher level.

Simple Machines continued:

• In the 1st century B.C.E., a Roman engineer named Vituvius made the water wheel practical.• This wheel-and-axel machine ground grain into flour.

Today’s Simple machines: Simple machines help us today, both as parts of complex machines and alone.

Lever – BroomInclined Plane - DrivewayWheel and axel – doorknobPulleys – operate many garage doors and

windows.Wedges – door stops.Screw – Thermos cap.

When put together these simple machines make up more complex ones:

Example: Hand – held can opener

• Each of its handles is a lever.•The turning knob is a wheel and axel.• The blade cuts using the principles of the wedge.

All Machines use . . . .

Force

• Sometimes we want to lift, push, or pull objects, or we may want to cut or break them.

• Some of these jobs require a lot of force.

Force

• When we use Simple Machines, we gain a mechanical advantage by increasing the amount of force we can bring to bear on an object.

How Simple Machines operate: Effort & Force

• The amount of force we apply to the machine.

Effort & Force

• We can apply less effort over a greater distance.

• More effort over a shorter distance.

Effort & Force

• Simple machines provide a gain in effort, or a gain in distance.

• Some simple machines change the direction of effort.

• Effort is measured in Newtons.• The Newton is the metric unit of force.