Unit Six

Introduction

In engineering professions, you can be asked to describe different mechanism quite often. In this unit you will revise and learn about some basic mechanisms and look at several ways of explaining how they work.

Objectives:
After this unit you should be able to:
- explain the principle of simple mechanism,
- explain how mechanisms work.

Tasks and Dates

This unit consists of two parts. Part one contains fine activities and part two contains four activities.

First of all you will have to think about the terms mechanism and machine. How would you describe the two terms? Read the text "Mechanisms and Simple Machines" to find out. Answer the reading comprehension questions in the quiz. Then go to the Mechanisms quiz and label the pictures of mechanisms. In the bicycle forum discuss the mechanisms, motions and forces that can be found on a bicycle.

Do the listening comprehension quiz. Listen carefully to the description and answer the listening comprehension questions. After that look at the picture of the little ducks in the forum and try to describe it. Paste your description to the forum.

Once you have studied how to describe a mechanism in a simple way go to the article about the diesel engine. Do the comprehension quiz. Then listen to the description of how a diesel engine works. Complete the missing words.
Finally describe how a vacuum coffee maker works. Use sequencers, express cause and effect. Compare your description with other students. Copy and paste it to a Vacuum coffee maker forum.

To study the ways of describing simple mechanisms and expressing cause and effect study the chapter called Language study.

Language Study

1.
For a simple description of mechanism and machines, we use ZERO conditional.
If/When the cylinder moves backwards and forwards, the driving wheel completes one full rotation.

Remember:
FORCE is APPLIED TO …
MOTION/MOVEMENT is TRANSMITTED e.g. Rotary motion of a cam is transmitted to a reciprocating movement of the connecting rod.

2.
Expressing cause and effect
The intake valve opens up, letting in air and moving the piston down.
(The intake valve opens up. It lets in air and moves the piston down.)

The piston moves back to the top, pushing out the exhaust.
(The piston moves back to the top. It pushes out the exhaust.)

As the piston reaches the top, fuel is injected. (The actions happen at the same time)