Transcript SOLIDS AND LIQUIDS - Lewiston School District

Levers
TESLA Simple Machines 2010
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
Force is a push or pull applied to an object.
Work = Distance X Force
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?)
How can a lever be used to complete a task (work) with the
least amount of effort (force)?
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New 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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Previous Knowledge
Share experiences with levers 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_________.
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Class Predictions (related to the focus question)
Preparing 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
The position of the fulcrum
What are we going to keep the
same
•The load that is lifted
•The arm of the lever
•Effort used: Paper Clips*
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*The # of paper clips might change, but our tool for measuring effort will not
Collecting Data
We need to keep track of our data and observations…
Using a Lever System to Measure Effort
“How can you lift two hex
nuts of load with only one
hex not of effort?”
Does moving the fulcrum impact the mechanical advantage a lever
can provide?
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Making Meaning Conference
What happened when we moved the fulcrum closer to the load?
What happened when we moved the fulcrum farther from the load?
What pattern can we find in the data?
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 Evidence
How can a lever be used to complete a task (work) with the
with the least amount of effort (force)?
I claim that…
I claim this because…
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Reflection/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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