Simple Machines Standard: Identify simple machines and explain their uses

1. Simple MachinesStandard: Identify simple machines and explain their uses

2. What is a Simple Machine? • A simple machine is a machine with few or no moving parts to which you apply just one force • Simple machines change the way work is done and make work easier

3. Simple Machines • Levers • Pulleys • Inclined planes • Wedge • Screw • Wheel and axle

4. Simple Machines • How did simple machines come about? • Used to hunt, gather plants, make clothes, build shelter, protection, warfare, move things • Copying nature such as: • Beavers cutting logs • Woodpeckers pecking on a tree trunk • Moles clawing their way through the dirt

5. Levers • Levers make it easier for people to lift heavy objects or open things. • Levers date back to prehistoric times and were probably used by early humans to dig for small animals or pry under rocks. • A lever is a bar that pivots on a fixed point. • For any type of lever you can identify three parts or ELF – effort, load and fulcrum. • The force that is exerted is the effort. • The object being moved or opened is called the load. • The fulcrum is the fixed point that allows a pivot to occur. The fulcrum does not move.

6. Levers-First Class • In a first class lever the fulcrum is in the middle and the load and effort is on either side • Think of a see-saw, crow bar, claw hammer, scissors, oars

7. Levers-Second Class • In a second class lever the fulcrum is at the end, with the load in the middle • Think of a wheelbarrow, nutcracker, paper cutter, bottle opener, hand truck

8. Levers-Third Class • In a third class lever the fulcrum is again at the end, but the effort is in the middle • Think of a pair of tweezers, broom, hockey stick, shovel, bat, fishing pole, arm • Brain Pop

9. Inclined Planes • An inclined plane is a flat surface that is higher on one end • Inclined planes date to prehistoric times • Ancient pyramids were built using inclined planes • Inclined planes make the work of moving things easier • Ramps, stairs, escalators and curved roads are inclined planes • You must travel a greater distance, but use less force • Brain Pop

10. Wedges • Two inclined planes joined back to back • The earliest wedges date to 2.6 million B.C. and were stone tools used for hunting and building • Unlike inclined planes, wedges move • Wedges are mainly used to split things apart • A knife, ax, arrowhead, zipper, nail, the bow of a ship, a plow, a doorstop and your teeth are all wedges

11. Screws • A screw is an inclined plane wrapped around a shaft or cylinder. • Screws date back to around 400 B.C. and were first used as hand-cranked water pumps • The inclined plane allows the screw to move itself when rotated. • Drills, propellers, light bulb threads and water bottle caps are examples of screws

12. Wheels and Axles • The wheel and axle are a simple machine • The wheel and axle dates back to around 4000 B.C. • The axle is a rod that goes through the wheel which allows the wheel to turn • Tires, a spinning wheel, faucets, doorknobs and windmills are examples of wheels and axles • Brain Pop

13. Pulleys • Pulley are wheels with a groove around the outside • A pulley needs a rope, chain or belt around the groove to make it do work • Pulleys date back to 4000 B.C. and were first used as part of a crane • A pulley changes the direction of the force • A flagpole, crane, clothesline, elevator, and window blinds are examples of pulleys • Brain Pop

14. Gears • A wheel with teeth • Used to transfer power • One gear cannot work on its own • Many gears are connected with chains • Gears move in opposite directions

15. Compound Machines • Simple Machines can be put together in different ways to make complex machinery.

16. Simple Machines Constructed Response: • Draw pictures of two simple machines that you could use to help you lift a heavy box • Label your drawings and include brief instructions on how to use the simple machine to lift the object.