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Introduction

It is often said that a clever person finds ways to work smarter rather than harder. A machine can be defined as a device that makes a job easier to perform. A simple machine is a machine that does one type of job and has few or no moving parts (see pictures above), whereas a compound or complex machine can contain many simple machines and can perform more complex jobs. In this unit we will be learning about the different types of simple machines and investigate how they make work easier to do. We will also perform some simple experiments and calculations on forces and the amout of work done. I think we can all agree that less work is definately smarter, so this unit will help all of us to be a bit more clever.



Key wordsexternal image simple-machines-kit.jpg


Simple machine, compound machine, force multiplier, distance multiplier, speed multiplier, lever (first, second and third class), inclined plane, wedge, screw, wheel and axle, pulley, gears, cams, cogs, effort, fulcrum (pivot), load, energy, work, force, friction, mass, weight, spring balance













Student work

1. Organising your student page: copy and paste all your work for Body at War into a new link you create on your student page entitled Body at War - your name. Then create a new link in your student page, entitled Making Life Easier - your name.
2. Working on our Glossary for Making Life Easier .

3. Ramps experiment follow-up. So... what is mechanical advantage?
Go to this website: http://library.thinkquest.org/CR0210120/Mechanical%20Advantage.html
Read the information and summarise in your notebook. Then click the "inclined planes" box. copy down the information, diagram and the questions.
Answer the questions then check your answers. Now... using what you have learned, fill-in the colum on your table of results by calculating the mechanical advantage produced by the cart and the block in your experiment. Lastly... answer any remaining Questions from the prac sheet you were given in class.

4. Following up from our evaluation of the ramps prac.
Homework: Go to MOSS > Year 9 Student Resources > Science > Making Life Easier
In there you'll find the Science Focus 2 Textbook pdf. Open and look at Unit 8, "Machines", p240-243.
Read through the information and answer questions 3, 4, 6, 7, 18, 19 and 20 on page 244.

5. Levers: classifying as 1st, 2nd and 3rd class levers and class prac.
March 18th Homework: Go to MOSS > Year 9 Student Resources > Science > Making Life Easier
In there you'll find the Science Focus 2 Textbook pdf. Open and look at Unit 8, "Machines", p247-250.
Read through the information and answer questions 2, 3, 4, 5, 6, 7, 8, 9 and 10 on page 250.


Play this interactive game, Simple Machines in the House and The Toolshed: **http://www.edheads.org/activities/simple-machines/**

...and in your notebook or on your wiki page give examples of simple machines you can find in two rooms of the house and then draw each of the four compound machines found in The Toolshed and label the simple machines that make them up.
Gears interactive:
http://www.media.pearson.com.au/schools/cw/au_sch_rickard_sd2_1/int/gears.html

¨ Recall that gears are usually wheels with teeth and have been used by human cultures for centuries
¨ List common examples of uses of gears
¨ Recall that gears can be used to magnify and/or change the direction of a force
¨ Define the terms driving gear and driven gear
¨ Describe the common ways gears can be joined – both contact and with chain/belt/etc.
¨ Compare the affect of gears in contact and joined by belts on the direction of the driven wheel (load)
¨ Explain how gears on a pushbike are used as force magnifiers and distance magnifiers
Describe the affect of using gears as distance magnifiers on the speed of a pushbike


6. Legal & Illegal ramps test.

7. Go to http://scifiles.larc.nasa.gov/kids/Problem_Board/problems/pulleys/sim1.swf and work your way through the Egyptian Pyramid builders problems. As you finish each level you are given a password to continue to the next level of increasing difficulty. These simulations will allow you to consider mechanical advantage to solve real-world problems using pulleys, levers and inclined planes. If you have not been provided with a printed version of the worksheets, fill in the worksheets on the website as you work through the simulations.


8. Processing Data Task: go to http://www.lon-capa.org/~mmp/kap4/cd095a.htm and use the interactive applet on inclined planes to fill in the following worksheet

9. Trebuchet Task:

10. How to write a lab report:

MA of pulleys.png
Force = Mass x Acceleration
(in this case, acceleration is gravity, 9.8 m/s/s)
Simple Machines Booklet - Reflection Questions;
1. What did you find most interesting about simple machines?
2. What concepts or aspects did you find...
i) the easiest
ii) the most challenging
3. What would you be interested to investigate further regarding simple machines?



Resources


Simple Machines Introduction Powerpoint -
Simple Machines Mechanical Advantage Powerpoint -
Videos on simple machines - http://educationalminimovies.com/SIMPLE-MACHINES.php
Simple machines information sheet http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm
Web page on mechanical advantage http://library.thinkquest.org/CR0210120/Mechanical%20Advantage.html




Videos

See how many simple machines you can find in these crazy Japanese Rube Goldberg (chain reaction) machines



Below is an example of someone who has way too much time on their hands



Honda ad using Rube Goldberg machines



Eureka! Videos - fun and informative