THE LEVER All tools are combinations of basic machines. Basic Machines: Wheel Screw Incline plane Pulley Lever
Question: What type of machine do you think a spanner is?
A lever doesn’t make you stronger, it only helps you make more use of the strength you already have. This allows you to do more work.
LEVERS in ACTION Levers can be found in many places. You may already use some of them on a regular basis. Here are a few,
All levers have 3 things in common: A Fulcrum A Load An Effort
Question: Where do you think the Fulcrum, Load and Effort are located in the following levers?
SOME MORE LEVER IN ACTION
STRUCTURES: TENSION (TIE) COMPRESSION (STRUT) TRIANGULATION
Tension activity:
Compression activity: Construct the following tubes using paper. (The square tube is 25mm square and the round tube is 25mm diameter. Which one can withstand the greatest load before buckling? Which one uses most material?
Construct 2 tubes about 6mm diameter and 50mm long. Now compare how easily you can buckle 1 tube by squeezing it and how difficult it is to pull the other one apart. Triangulation activity: Construct each of the following frames using straws and pins. Which is the strongest?
TENSION and COMPRESSION are types of FORCES
Some materials are better in tension than in compression, while others are better in compression than tension.
Click on this link and research which materials are good in tension and which are good in compression.
NOW ANSWER THE FOLLOWING TASK SHEET Remember to save the worksheet to your server.
RESEARCH The Romans conquered much of Europe including a large part of Scotland. Evidence of Roman occupation can still be found as close as Falkirk. One reason for the success of the Roman Empire was its well-equipped army, which had access to some ferocious weaponry including the Ballista and Onager. However, there was much more to the Romans than their weaponry. Individually, produce a PowerPoint presentation about the Roman Invasion of Britain. Aim to create about 5 minutes worth of material that you can present to your class. This link might help you get started.
ACTIVITY The Onager made use of a machine you should be familiar with by now, the LEVER.
Your task is to design and make your own Onager. 1) Idea sheets 2) Dimensioned final idea 3) Photographs of construction 4) Record of testing, (Distance achieved) 5) Finished InDesign record of activity