TESLA Simple Machines 2010

Levers

The Big Idea of this Investigation

A simple machine is a mechanical device that makes work easier by magnifying, modifying, transferring, or changing the direction of applied force. Simple machines are the elementary "building blocks" of which all complicated machines are made.

Knowledge We Will Build on From Prior Investigations

Work = Distance X Force

Force is a push or pull applied to an object.

ENGAGING SCENARIO

Now that we understand a relationship exists between force and work we will begin to test a few simple machines. Some machines allow us to do work while applying less force. This is called mechanical advantage. The first machine we will test is the lever. Levers have the ability to transmit and sometimes magnify force. As groups of scientists you will be asked to work with some new materials and keep accurate records in your scientist notebook. You will need to gather and provide evidence of how a lever can complete a task (work) with the least amount of effort (force).

• What is the problem we need to solve? • What do we need to investigate?

Discuss ideas with a partner for a possible focus question. Your focus question should be connected to what the scenario wants us to do…

Focus Question (What is the problem?)Focus Question (What is the problem?)

How can a lever be used to complete a task (work) with the least amount of effort (force)?

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New VocabularyNew Vocabulary

There are four components to the lever: arm, load, effort and fulcrum.

For this task we need to determine where to place the fulcrum (pivot point) on the arm (beam or bar) so that a load (the object to be moved) can be moved with the least amount of effort (force).

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Prediction (related to the focus question) Prediction (related to the focus question)

Prediction:I think that if we move the fulcrum _______________ the least amount of effort would be needed to move the load because_________.

Prediction:I think that if we move the fulcrum _______________ the least amount of effort would be needed to move the load because_________.

Previous Knowledge Previous Knowledge

Share experiences with levers related to the focus question.Share experiences with levers related to the focus question.

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Class Predictions (related to the focus question) Class Predictions (related to the focus question)

Preparing the InvestigationPreparing the Investigation

Each group will be given 2 plastic cups, a fulcrum, a pegboard beam, paper clips, 3 hex nuts and two pieces of tape. You will use these materials to build your lever system.

What are we going to change What are we going to keep the same

*The # of paper clips might change, but our tool for measuring effort will not

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The position of the fulcrum• The load that is lifted• The arm of the lever• Effort used: Paper Clips*

Collecting DataCollecting Data

We need to keep track of our data and observations…

Using a Lever System to Measure Effort

Does moving the fulcrum impact the mechanical advantage a lever can provide?

“How can you lift two hex nuts of load with only one hex not of effort?”

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Making Meaning ConferenceMaking Meaning Conference

What pattern can we find in the data?

What happened when we moved the fulcrum closer to the load?

What happened when we moved the fulcrum farther from the load?

How were you able to lift 2 hex nuts of load with 1 hex nut of effort?

What is the mechanical advantage a lever can provide? How can a lever make work easier?

Claims and EvidenceClaims and Evidence

I claim that… I claim this because…

How can a lever be used to complete a task (work) with the with the least amount of effort (force)?

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Reflection/ConclusionReflection/Conclusion

Revisit your original prediction… Explain how the evidence did or did not support your original prediction?

My prediction was accurate because…..I wish to revise my prediction because…

What did you learn…

What really surprised you…

What new questions do you have…

What would you like to know more about…

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