1. Ch 13 part 2 Simple Machines Pages 426-431 http://www.dailymotion.com/video/x3cvmov ` http://www.dailymotion.com/video/x3cvmov http://dai.ly/x3cvmov

2. A.Machines and work 1. Work is done when force causes an object to move 2. Machine= device that changes the direction or amount of force needed to do work ◦ DO NOT reduce work= just make it easier to do the work 3. The amount of force decreases BUT the force must be applied over a greater distance

3. B.Simple Machine #1 Pulley https://youtu.be/aMx7nIIH9ik?t=47s https://youtu.be/aMx7nIIH9ik?t=47s 1.Pulley= consists of a rope or cable that runs through a grooved wheel 2.Simple pulley makes work easier by changing the direction of force needed to do work 3.Block and tackle= system of pulleys that make it easier to lift very heavy objects  Block= pulley and the tackle is the rope through the pulleys

4. C.Simple machines #2 Wheel and Axle https://youtu.be/P7xu9O0miEc?t=47s https://youtu.be/P7xu9O0miEc?t=47s 1. Wheel and axle= made of a circular object and a shaft ◦ Reduces the amount of force needed to do work ◦ Door knob, steering wheel,

5. Stop and Think 1. What is a machine? ◦ A device that changes the direction or the amount of force needed to do work 2. How are a pulley and a wheel and axle alike and different? ◦ Both have wheels ◦ A pulley has a rope & it changes the direction of the force ◦ A wheel& axle has a shaft & it reduces the amount of force needed to do work 3. When a wheel and axle as well as a pulley make it easier to raise a bucket of water from a well, has the work changed? ◦ The amount of work has not changed b/c the amount of work has stayed the same- the machine made it easier to do the work

6. D.Simple machine #3 Lever https://youtu.be/OdM2jWg2uEE?t=46s https://youtu.be/OdM2jWg2uEE?t=46s 1. Lever= type of simple machine in which a stiff bar rotates around a fixed point called the fulcrum ◦ A see-saw is a fulcrum that changes the amount of force needed to move an object ◦ Further away the fulcrum is from the person the easier the lever is to use

7. E.Simple Machine #4 Inclined Plane https://youtu.be/E_ErI0QjNos?t=49s https://youtu.be/E_ErI0QjNos?t=49s 1. Inclined plane= simple machine consists of a flat surface with one end higher than the other ◦ Doorstops & axes are inclined planes 2. Screw= smooth metal rod with tin inclined planes wrapped around it ◦ Archimedes invented the screw in ancient Egypt (3 rd century B.C) to move water from the ground

8. 3. Wedge= inclined plane used to separate objects

9. Stop and Think 1. What common playground equipment is a lever? Which is an inclined plane? ◦ See-saw (teeter totter) ◦ Slide 2. How is the movement of rolling a weight up an inclined plane different from climbing stairs? ◦ Climbing stairs requires more force 3. What kind of simple machine is a bottle opener? ◦ A lever

10. F.Complex Machines https://youtu.be/k_aTRL2Ircw https://youtu.be/k_aTRL2Ircw 1. Complex machine uses 2 or more simple machines 2. Many use electricity, magnetism, gravity, burning fuel, or human force to use

11. Stop and Think 1. What is a complex machine? ◦M◦M achine that uses 2 or more simple machines 2. How are the pedals of the go cart similar to the rudder of a sailboat? ◦B◦B oth use levers 3. What parts of a complex machine work together to make the complex machine operate? ◦A◦A ll of the simple machines work together to make the complex machine operate!