Machines Making Work Easier

Essential Question What effect do simple machines have on work?

Machines A machine is a device that makes work easier by changing the size or direction of the force. In general, machines allow you to overcome gravity and/or 2) friction in order to move something!

Types of forces involved with machines a. Effort Force – force applied to the machine b. Resistance Force – force applied by the machine to overcome the resistance of the object to be moved.

NOTE!!! REMEMBER THE LAW OF CONSERVATION OF ENERGY! Energy can neither be created nor destroyed. However, energy can change from one form to another. You can never get more work out of a machine than you put into it because some energy is always lost to heat (friction) .

SIMPLE MACHINES A simple machine is a device that does work with only one movement.

LEVER: Definition A lever is a bar that is free to pivot, or turn, about a fixed point, the fulcrum. A lever can be used to multiply the force or change the direction of the force.

Examples

PULLEY: Definition A pulley is a grooved wheel with a rope or chain running along the groove.

Examples

WHEEL & AXLE: Definition A wheel and axle is a simple machine consisting of two wheels of different sizes that rotate together.

COMPONENTS OF A WHEEL AND AXLE SYSTEM The larger wheel – usually the effort force may not look like a typical circular wheel (crank handle or a faucet) The axle (smaller wheel) - exerts the resistance force.

Example

INCLINED PLANE: Definition An inclined plane is a flat, sloping surface over which objects can be moved to higher level.

WEDGE: Definition A wedge is two inclined planes put back-to-back.

Examples

SCREW (BOLT): Definition A screw or a bolt is an inclined plane wrapped around a central point or a winding inclined plane.

Examples

Name the simple machines.

COMPOUND MACHINES A compound machine is a combination of two or more simple machines. For Example: A stapler Arm– lever (push the staple through the paper) Points of the staple – Inclined Planes

What does the FUTURE hold? Robotics -the science of designing artificial machines to complete work for humans. NASA's next Mars rover mission will launch in 2009. Twice as long and five times as heavy as the Mars Exploration Rovers, the Mars Science Laboratory will collect Martian soil and rock samples and analyze them for organic compounds and minerals.

What does the FUTURE hold? Bionics -- the science of designing artificial replacements for parts of the human body.

What does the FUTURE hold? Nanotechnology --A new branch of science called nanotechnology is aimed at producing chemical clusters of less than 50 atoms, electronic components, and even machines or robots by constructing them molecule by molecule.

Assessment Name the simple machines that make up the compound machines.