Balancing Pencils
Lesson 2
TESLA Balance and Motion 2011
The Big Idea of this Investigation
Our physical world is governed by the properties
and interaction of objects and how force affects
motion.
ENGAGING SCENARIO
The Lewiston Toy Company likes the information you
have written in your science notebooks about toys that
balance. They would like for you to test one more model
that they think will help make some good balancing toys.
They have sent us some materials and printed information
that may help us. They also need us to continue to keep
accurate records and labeled drawings in our science
notebooks so we can report what we found out in a couple
of weeks.
• What is the problem we need to solve?
• What do we need to investigate?
Kit Inventory
These are the objects that have been sent to us by the
Lewiston Toy Company. I have put them in this large bag.
Let’s see if we can identify them.
• What color/shape is the object?
• Where have you seen this object before?
• What do you think we will use this for in the unit?
Here is the new model the Lewiston Toy
Company sent us to test. It looks like an
arm that is holding on to a pencil. We
need to use the knowledge from our last
lesson to balance the picture on a craft
stick. Our goal is to make the picture
balance on the pencil point.
What is a stable position?
Where should we place counterweights to balance an object and
make it stable?
Now lets see if we can find a way to balance the picture on
the pencil point.
Making Meaning Conference
Where did you put the clothespins to make a stable system?
Can you make a stable system with no clothespins? One? Two?
Why?
Now the Lewiston Toy Company has a greater challenge
for us. They are really hoping you can find a way to make
a real pencil balanced and stable on its point.
In addition to our clothespins, the Lewiston Toy Company
has sent us some flexible, aluminum wire that may help
us solve our problem, but remember… Is an object
balanced if it is attached to the craft stick?
Focus Question
(What is the problem?)
Discuss with your group of scientists a possible focus
question for this investigation.
How can we use clothespins and aluminum wire to
balance a real pencil on its point?
Prediction (related to the focus question)
I think that if we ___________________________________,
the pencil will balance on its point on a craft stick. I think
this because…
NOTEBOOK ENTRY
Solving our Problem
Scientists always try to make careful observations.
Test your ideas to see if you can solve the problem. If you think
you found a way to balance a pencil on its point on a craft stick ,
make a drawing of your design in your science notebook. Be sure
to label all of your drawings.
Sometimes scientist like to record the ideas
that don’t work because these ideas can also
help us understand the problem.
NOTEBOOK ENTRY
Making Meaning Conference
How were you able to make the pencil balance on its point?
Were you able to balance the pencil without wire or clothespins?
Does it matter where you put the wire and clothespins?
How could you balance a fork on its point on a craft stick?
How could you balance a paper cup on a tight string?
What is a strategy for balancing an object on its point?
Claims and Evidence
Use your own words, or words from the word wall, to help
you complete the following sentences in your science
notebook.
I claim that to balance a pencil or other object on one point,
___________________ need to be added __________ the
balance point. I know this because…
NOTEBOOK ENTRY
Reflection/Conclusion
Revisit your original prediction and respond to one of the
following stems:
My prediction was accurate or was not accurate because…..
I wish to revise my prediction because…
My original thinking has changed because…
What did you learn…?
What really surprised you…?
What new questions do you have…?
What would you like to know more about…?
NOTEBOOK ENTRY