1. Warm up 1)Write a definition for each of the following: Gravity Force Inertia 2) Identify the forces acting on this crate on a ramp

2. Machines  Machine: A device that makes work easier by changing the size or direction of a force.  Simple Machine: Basic mechanical devices that alter the magnitude or direction of a force.  Compound Machine: Machines that are made of two or more simple machines.

3. Simple Machines Rap

4. Lab  Wear safety glasses.  Compare the force necessary to move the weight between the examples of each simple machine.  Read the applied force on the spring scale as you move the weight, and record it on your lab sheet.  Decide what makes that simple machine more effective.  Answer the questions at the end of the lab sheet.  The lab sheet will be collected at the end of class.

5. Lab Discussion  Thinking about how the simple machines worked, describe what a machine does. How does it make work easier? It changes the magnitude or direction of a force

6. Lab Discussion  Thinking about how the simple machines made work easier, what do you think the term mechanical advantage means? The number of times the machine multiplies force

7. Lab Discussion  What do you think work is? Scientists have a specific definition for work. It has two components. What do you think they are? Work = Force x Distance

8. Lab Discussion  CONSERVATION OF ENERGY  No machine can increase both the magnitude and the distance of a force at the same time.  When a machine produces an increase in force, there is always a proportional decrease in the distance moved.  When a machine produces an increase in distance, there will be a proportional decrease in force.

9. What is a Pulley?  The mechanical advantage is increased when you increase the number of ropes that support the moveable pulley. A pulley consists of a grooved wheel that turns freely in a frame called a block. How do you increase its mechanical advantage?

10. What is a Lever?  A lever is a rigid bar that rotates around a fixed point called the fulcrum.  How do you increase its mechanical advantage? The mechanical advantage of a lever is increased when either the effort is moved further away from the fulcrum or the load is shifted closer to the fulcrum, or both.

11. What is a Wheel and Axle?  The mechanical advantage of a wheel and axle is increased when the diameter of the wheel is larger than the diameter of the axle.  The wheel and axle consists of a large wheel rigidly secured to a smaller wheel or shaft, called an axle. When either the wheel or axle turns, the other part also turns. If the wheel turns and the axle remains stationary, it is not a wheel and axle machine.

12. What is an Inclined Plane?  The mechanical advantage of an inclined plane is increased when the slope is longer relative to the height. An inclined plane is an even sloping surface. The inclined plane may slope at any angle between the horizontal ( ---------- ) and the vertical ( | ).

13. What is a Wedge?  The mechanical advantage of a wedge is increased when the length of the wedge is longer relative to its height. The wedge is a modification of the inclined plane. Wedges are used as either separating or holding devices.

14. What is a Screw?  The mechanical advantage of a screw is increased when the distance between threads (called the pitch) is decreased while keeping the radius of the screw the same.  The screw is also a modified version of the inclined plane. Think of the threads of the screw as a type of circular ramp (or inclined plane).

15. Ticket out the Door  Briefly explain what a simple machine is.  Turn in your lab packet as you leave.