Activity 3.2.1: Simple Machines

Activity 3.2.1 – Simple Machines

Purpose How many simple machines have you come into contact with since you woke up this morning? If you were to list all of the common objects that you interact with on a daily basis, you would be astonished at the number of them that are mechanisms that employ simple machines.

A simple machine is any of several elementary mechanisms that are used to transmit or modify force or motion. There are six simple machines: lever, wheel and axle, pulley, inclined plane, wedge, and screw. If you had to climb a set of stairs or walk up a ramp to get from one level to another, then you used an inclined plane. If you used a knife to cut a piece of bread, then you have used a wedge. If you had to pull on a string to open or close a set of window blinds, then you have used a pulley. When you turn a door handle, you are interacting with a wheel and axle. When you use a hole punch to cut holes through a stack of papers for placement in a 3-ring binder, the handle that you push down on is a 2nd class lever. When you flip a light switch, you are using a 1st class lever.

A mechanical device, like the product that you have selected for the focus of your reverse engineering project, is a system that is often made up of several simple machines working together to make an object perform a desired task. When a mechanism uses more than one simple machine to perform work, the device is called a compound machine. An example of a compound machine is a nail clipper, which employs wedges and two different types of levers to transfer a person’s effort force to the resistance; in this case the person’s nail.

The functional analysis of your mechanical device will reveal the simple machines that it employs to perform its intended function.

Project Lead The Way, Inc. Copyright 2007 IED – Unit 3 – Lesson 3.2 – Activity 3.2.1 – Simple Machines – Page 1 Equipment  Digital Camera  Computer  Microsoft Paint or other graphic manipulation software  Printer  Engineer’s notebook  Number 2 pencil

Procedure In this activity you will perform a pre-dissection functional analysis of your selected product to identify any simple machines that are used in its function.

Perform a visual inspection of the exterior of your reverse engineering product. Use the table below to identify the number of simple machines that you see. Briefly describe the parts that make up the simple machine (you may invent names for the parts), and what their functions are. This may also include giving details about the simple machine, such as the class of lever that is present. If the table is too small to accommodate the necessary amount of information, you may recreate the table in your engineer’s notebook and use that instead. Not all mechanical objects are comprised of all six simple machines. Therefore, it is understood that some parts of the table may have to be left blank.

Simple # of Description Machine Occurrences Lever

Pulley

Wheel & Axle

Inclined Plane

Use a digital camera to take photographs the parts of the object that function as simple machines. Clean up the images on the computer using a graphic manipulation program. Place the photographs in your engineer’s notebook. Next to each image, explain what type of simple machine is present, and how it is used to make the mechanical device function.

Project Lead The Way, Inc. Copyright 2007 IED – Unit 3 – Lesson 3.2 – Activity 3.2.1 – Simple Machines – Page 2 Project Lead The Way, Inc. Copyright 2007 IED – Unit 3 – Lesson 3.2 – Activity 3.2.1 – Simple Machines – Page 3 Conclusion 1. What are the six simple machines that make up mechanical systems?

2. Generally speaking, what is the purpose of a simple machine?

3. What is the difference between a simple and a compound machine?