# Simple Machines.pdf

6 Nov 2022
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### Simple Machines.pdf

• 1. REVIEW What is heat transfer? What are the 3 forms of heat transfer?
• 2. Learning Goal/s 1. Describe how simple machines make work easier and faster. 2. Enumerate the different kinds of simple machines. 3. Manipulate simple machines to describe their characteristics and uses.
• 3. Through the centuries, humans have been challenged to make life easier. Humans have invented tools to make work less difficult. These tools are commonly known as machines. The tools most people think about when they hear the word machines are actually a combination of two or more simple machines.
• 4. Machines are devices that make your everyday tasks easier. They make you do more work with least effort. Look around your house, can you identify the machines that you use everyday?
• 5. Lesson Presentation Simple machines are mechanical devices that are used to make work easier, faster and more accurate. They help save time and effort. They are not expensive and are easily available when needed. It is good to keep them around for your convenience. Work may be defined as force acting through a distance.
• 6. Energy: Ability to do work Work= Force x Distance Force: A Push or a Pull Definitions:
• 7. The 6 Simple Machines Lever Pulley Wheel and Axle Wedge Screw Inclined Plane
• 8. Inclined Plane
• 9. Inclined Plane  The Egyptians used simple machines to build the pyramids. One method was to build a very long incline out of dirt that rose upward to the top of the pyramid very gently. The blocks of stone were placed on large logs (another type of simple machine - the wheel and axle) and pushed slowly up the long, gentle inclined plane to the top of the pyramid.
• 10. Inclined Planes  An inclined plane is a flat surface that is higher on one end  Inclined planes make the work of moving things easier
• 11. Screw The spiral ridges or thread serves as inclined plane. This allows movement from a lower position to a higher position It used to fasten objects together
• 12. Wedges  Two inclined planes joined back to back often form a sharp, thin edge  Wedges are often used to split things, to separate or to cut objects. Some are used to hold or secure things.
• 13. Lever  It is a bar, a pole or a long rod that can be used to lift push, or pull things.  Fulcrum- the part that moves at a point  Load- the weight lifted  Effort- applied force (to lift an object)
• 14. Fulcrum is between EF (effort) and RF (load) . First Class Lever
• 15. First Class Lever .  Common examples of first-class levers include crowbars, scissors, pliers, tin snips and seesaws.
• 16. RF (load) is between fulcrum and EF The load is placed closer to the fulcrum, so that less effort will be applied. Second Class Lever
• 17. Second Class Lever  Examples of second-class levers include nut crackers, wheel barrows, doors, and bottle openers.
• 18. EF is between fulcrum and RF (load) Third Class Lever
• 19. Third Class Lever  Examples of third-class levers include tweezers, arm hammers, and shovels.
• 20. Pulleys  Pulley are wheels and axles with a groove around the outside  A pulley needs a rope, chain or belt around the groove to make it do work
• 21. Diagrams of Pulleys Fixed pulley: A fixed pulley changes the direction of a force; It used to lift or lower the objects such as a flag. Movable Pulley: This helps in gaining more force when lifting an object. It raises or lowers the load attached to the other end of the rope which passes around a groove that is pulled at the other end. Ex.Elevator
• 22. Block-and-tackle PULLEY  The effort needed to lift the load is less than half the weight of the load.  The main disadvantage is it travels a very long distance.  Ex.Venetian Blinds
• 23. WHEEL AND AXLE  It is made up of the wheel that revolves around the shaft or rod called the axle  The axle is stuck rigidly to a large wheel. Fan blades are attached to the wheel. When the axel turns, the fan blades spin.
• 24. GEARS-Wheel and Axel  Each gear in a series reverses the direction of rotation of the previous gear. The smaller gear will always turn faster than the larger gear.
• 25. Rube Goldberg Machines  Rube Goldberg machines are examples of complex machines.  All complex machines are made up of combinations of simple machines.  Rube Goldberg machines are usually a complicated combination of simple machines.  By studying the components of Rube Goldberg machines, we learn more about simple machines
• 26. Project: Simple Machine Toy  Create a simple machine toy using available materials at home  Be creative and resourceful  Take photos/videos while doing the project.  Explain the process and discuss the simple machines used.  Deadline: March 2, 2022
• 27. Sample project
• 28. Sample project