# Year 8: Simple Machines

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This week in year 8 Science we are starting a unit of work on simple machines, which includes inclined planes, wedges, screws, levers, pulleys, wheels and axels. I have saved some links to good sites in Delicious. The first task for students is to create a mind map (use Inspiration, Freemind or Bubbl.us) to show the six different types of simple machines with at least one pictorial example of each. You could also try the Google Labs app “Squared”, which produces a table of information including the type of simple machine, an image and a description.

The purpose of a machine is to reduce the effort required to do work – this is achieved by increasing the speed or increasing the distance,  while reducing the force required. This concept is represented in the equation W = F x D (Work = Force x Distance). Before the invention of the steam and combustion engines, much work was achieved using simple machines and human or animal labour. In the picture above, a wooden block from a sailing ship, a pulley is a wheel and axle used to change the direction and decrease the effort required to lift a weight. Another example is the ‘shaduf’, an ancient Egyptian machine (lever) used for moving water from the river up to the bank, shown below.

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1. Create a quiz (using “MyStudiyo” or Powerpoint) about simple machines, with at least ten questions.
2. Create a poster with a compound machine (eg. A push-bike, excavator, front-end loader etc) and label each component machine. Make sure you include information about how your machine works. “How Stuff Works” is a great site to help you with this.
3. Create a photostory explaining about each simple machine or how a compound machine works. Make sure the images you use are copyright free – use Flickr (Advanced Search – Creative Commons) or Google Image Search (Advanced – Free to reuse)
4. Invent a machine and create an advertising brochure about what it does and how it works.
5. Do this webquest about simple machines which includes creating a table, a model and a poster.
6. Edheads has a great site for learning more about simple and compound machines.

Congratulations Rachel on this outstanding example of a Bubbl.us mind map about Simple machines. Well done!

# Compound Machines

A bicycle is an example of a compound machine – a machine made up of several simple machines. A bicycle includes levers and fulcrums, wheels and axles, gears and a pulley. Your task is to find and print a picture of a compound machine – a crane, an auger or an excavator are all examples. Create a poster labelling all the simple machines in your picture. You may find “How Stuff Works” and “Library Think Quest” useful sites to assist your understanding of simple machines. How Stuff Works also has some useful videos showing pulleys, levers and different compound machines.

Here are two of the posters that year 8 students produced, labelling the simple machines within their compound machine. Henry took some pictures of the grain header on his farm to show inclined planes, levers, pulleys and gears.

# Forces and Simple Machines

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This week in Year 7 Science we will be looking at Forces – conducting experiments using contact forces (friction, bouyancy and surface tension) and non-contact forces (gravity, magnetism and electr-static forces). In Year 8 Science we will be studying Simple Machines – inclined planes, levers, the wheel and axle, pulleys and gears. One of the best sites to find resources for these units of work is Science-Class-net. There are hundreds of activities, demonstrations, experiments, graphic organisers, quizzes and slideshows about all science topics. I am very grateful to Mr. Poarch, a retired science teacher, for sharing all his wonderful resources collected over a lifetime of teaching and making them accessible on the internet.