Print bookPrint book

Week 21 - Machines Help Us Do Work

Site: MoodleHUB.ca 🍁
Course: Science 8 LearnNet
Book: Week 21 - Machines Help Us Do Work
Printed by: Guest user
Date: Tuesday, 16 September 2025, 8:10 AM

Description

Week 21 - Machines Help Us Do Work

Table of contents

Introduction

Read pages 258 - 260 & 315 - 320
 
Mechanical Systems

Silly Machines

Rube Goldberg is a cartoonist famous for his complicated silly machines for doing simple tasks. The first is a method of sharpening a pencil, the second is a method of keeping a store window clean.



To find out more about this interesting man go to this site.

http://www.rube-goldberg.com/


These silly cartoons do illustrate one important concept of mechanical systems. Large complicated machines are always composed of several smaller machines.

© 2002 Alberta Online Consortium

Lesson 1

Lesson 1: Introduction to Mechanical Devices


You use machines on a daily basis.

You use a machine, the can opener, to open a can of corn or peas.
If you need to fix a broken piece of furniture you might use a machine called a screw.



A baseball player or hockey player uses a machine, called a lever, every time they swing a bat or take a slap shot. A machine is any device that makes work easier by changing the size or direction of the force applied to it.
Humans and some animals use machines to meet a particular need. In this activity, you will investigate examples of mechanical devices used to meet a human need. If time permits, you will build a short multimedia presentation on these mechanical devices.

Did You Know?

The tin can was invented 130 years before the can opener. For a long time a hammer and chisel were the only ways to open cans.

Exercise 1.1: Intro to Mechanical Devices

Ancient Technology
The Great Pyramid of Giza in Egypt was built nearly 5000 years ago using blocks of limestone. The workers needed to move 2.3 million blocks each weighed more than 1 tonne. How did they do that?

 

 
Modern skyscrapers and towers defy gravity and reach hundreds of meters into the air. Instead of limestone blocks, the builders of today use steel and concrete to construct these monuments to humanity's progress. How do they do that?


.

Lesson 2

Read pages 258 to 260 and 315 to 320

Lesson 2: Trial and Error
Scientists, engineers, and manufacturers of machines often rely on trial and error to construct devices or to fix errors. Typically, they try one thing, and if it doesn't work, they try something else. The development of rockets was no exception.


Rockets have been used for centuries. From fireworks to Intercontinental Ballistic Missiles to the Space Shuttle, humans have used rockets as weapons of war, for celebrations, and to explore the last frontier. In this lesson, you will learn more about rockets and then build your own film canister rocket. As you read through the history of rockets, be sure to note the failures that occurred as well as the successes.

 

Exercise 1.2: Rocket History


© 2002 Alberta Online Consortium

.

Lesson 3

Read pages 258 to 260 and 315 to 320

Lesson 3: Meeting Human Needs
 

Prehistoric men and women spent most of their waking hours hunting and foraging food. They had little choice since bacteria and moulds would quickly attack and spoil their food. This was especially true in warmer climates. Throughout human history, different techniques and technologies have been developed to preserve food. The earliest forms of food preservation where smoking, drying, salting, fermenting, freezing, and pickling. Today, modern refrigerators and freezers are the primary methods of storing and preserving food. In this activity, you will trace the history of food preservation and, in particular, will trace the history of the modern day refrigerator.
Modern day refrigerators slow the growth of bacteria and fungi which helps to preserve food for long periods of time.

  Exercise 1.3: Refrigeration

 

Section1 Notes

You have two options for your Section 1 Quiz - a multiple choice quiz or a written response quiz. You may choose to write the multiple choice or the written response. You only need to write one of them, so the choice is up to you! You are allowed to try both quizzes if you want, but it is not required.

The quiz attempt with the highest grade will be the one that is recorded on your report card.

The multiple choice quiz has 10 multiple choice, matching, and true/false questions. You have 15 minutes to complete it. As soon as the quiz submitted it will be auto-graded and you will receive a grade immediately.

Click the image above to start your quiz

The written response quiz has 5 short answer questions. Your responses must give a complete and detailed answer to the question. You have 20 minutes to complete the quiz. This quiz needs to be manually marked by your teacher, so you may have to wait a few days to get feedback and a grade.

Click the image above to start your quiz