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DISCLAIMER This Presentation may contain Copyrighted Material, DO NOT DISTRIBUTE Force and Motion STARS Teacher Workshop Sunshine State Standards Force and Motion Standard SC.C.2.2.1 Recognizes that forces of gravity, magnetism, and electricity operate simple machines. We well review gravity, magnetism and electricity, and complete a number of activities that demonstrate how they can operate a simple machine. What is a simple machine? What is Simple Machine? A device for overcoming resistance at one point by applying force at some other point A simple device, such as a lever, pulley, or inclined plane; a machine without moving parts Examples of Simple Machines Lever Inclided Plane Wedge Pulley Wheel and Axle Screw The Three Simple Machines The Lever The Inclined Plane A simple machine consisting of a rigid bar pivoted on a fixed point and used to transmit force, as in raising or moving a weight at one end by pushing down on the other. The inclined plane is a kind of simple machine with slanted surface. The Pulley The pulley is a simple machine made of a rope or chain wrapped around the wheel. Other Machines Simple The Wedge The Wheel and Axle A simple machine consisting of The wedge is two inclined planes joined back to back. The wheel and axle is a simple machine made of a large wheel attached to a post or axle. The Screw The screw is an inclined plane wrapped around a post. Gravity and Simple Machines What is Gravity? Gravity is a Force which pulls objects downward toward the earth. A pulley can be used to make work seem easier by change the direction of force to work with gravity rather than against it Gravity The Lever Activity We will use the principles governing a lever to calculate how much weight is needed to balance the level on the fulcrum. Magnetism Electricity and Simple Machines What is Magnetism What is Electricity? a class of physical phenomena that include the attraction for iron observed in lodestone and a magnet, are inseparably associated with moving electricity, are exhibited by both magnets and electric currents, and are characterized by fields of force The physical phenomena arising from the behavior of electrons and protons that is caused by the attraction of particles with opposite charges and the repulsion of particles with the same charge. How can electricity be used with simple machines? Magnetism and Electricity come together to create a motor which can be used with simple machines. Simple Machines and Motors The Screw Screw are often twisted into wood or metal surfaces using drill Wheel and Axle The Pulley The Motor What is a motor? A device that converts any form of energy into mechanical energy, especially an arrangement of coils and magnets that converts electric current into mechanical power. In most DC electric motors, the rotor is an electromagnet that turns within a shell of stationary permanent magnets. The rotor will spin as long as this current reverses each time its magnetic poles reach the opposite poles of the stationary magnets. The most common way to produce these reversals is with a commutator. A simpler commutator has two curved plates that are fixed to the rotor and connected to opposite ends of the wire coil. The Motor Hand on Activity The Human Motor DC Motor Applet http://www.sciencejoywagon.com/physicszone/lesson/other pub/wfendt/electricmotor.htm The Motor (Activity) Building a motor References Proteacher http://www.proteacher.com Enchanted Learning http://www.enchantedlearning.com/physics/machines/Lev ers.shtml Physical Science http://www.sirinet.net/~jgjohnso/simple.html Dirtmeister http://teacher.scholastic.com/dirtrep/simple/pulley.htm UBC Let’s Talk Science Partnership Program http://www.gss.ubc.ca/LTS/electromagnetic_motors.html