Balancing Crayfish
Lesson 1
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 is thinking about making
some toys that balance. They would like for you to test
some models that they think will help make good balancing
toys. One of the models is a crayfish. The Lewiston Toy
Company needs your help in testing these models to see if
they will work. They have sent us some materials and
printed information that may help us. They also need us 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?
New Vocabulary
Here is one of the models the Lewiston Toy
Company sent us to test. It looks like a paper cut out
of a crayfish. A crayfish is a macroinvertebrate, or
freshwater insect, that can be found in our local
rivers and streams. The Lewiston Toy Company is
hoping that you can find multiple ways to balance
the crayfish on your fingertips.
When you try to balance an object it can only rest on your
finger. You can’t pinch the object or attach it with something like
tape. Lets demonstrate this idea using a ruler or yardstick.
Now lets see if you can find a way to balance the crayfish
on your finger.
Many of you have found one way to balance the crayfish, but the
Lewiston Toy Company is hoping that we can find multiple ways to
balance this object. For example; On its side, tail, or head.
They have sent along some clothespins that may help us solve our
problem, but remember… Is an object balanced if we just pinch it to
our finger with a clothespin?
Focus Question
(What is the problem?)
How can we use the clothespins to make the crayfish
balance in more than one way?
NOTEBOOK ENTRY
Prediction (related to the focus question)
I think that if we ___________________________________
you will be able to balance the crayfish in more than one
way.
I think that there are __________different ways we can
balance the crayfish.
Sometimes a scientist needs to explain their thinking
with models and drawings because their thoughts are
difficult to put in words.
Record examples of the different ways you think you can balance the
crayfish in your science notebook. Scientists use labels and pay
attention to detail so other people can understand their drawings.
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 new way to make the crayfish balance, 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
help us understand the problem.
NOTEBOOK ENTRY
Making Meaning Conference
What are some new ways you were able to balance your crayfish?
What did you do to get the crayfish to balance on its nose?
When you use clothespins to balance an object, does it matter
where you put the clothespins?
New Vocabulary
Counterweight: When you put a weight, like a clothespin, on an
object to make it balance, it is called a counterweight. You can use
counterweights to make objects balance in new ways.
Where should you put clothespins to balance the crayfish on its side?
How could you make the crayfish balance straight up and down on its tail?
The Lewiston Toy Company will be very pleased with
what we have learned so far about balancing objects.
When we used the counterweights to balance the crayfish on its
nose, this is called a stable position. The crayfish was steady
and it did not fall over. When I give it a little push, it wobbles
back and forth but does not fall over. The crayfish always
comes back to a stable, balanced position on its balance point.
Now the Lewiston Toy Company would like us to test some
new shapes to see if we can make them balance in multiple
ways. This time instead of using our finger as the balance
point, they would like us to use a craft stick taped to our
desk.
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 new way to make one of the objects balance, 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
What are some of the ways you were able to balance the arch?
What are some of the ways you were able to balance the triangle?
How can you tell if an object is stable?
Does the location of your clothespins make a difference?
Where is the best place to put counterweights on a crayfish? arch?
or triangle?
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 we can balance different objects in many ways.
I know this because…
I claim that adding ______________ can help us balance
an object. I know this because…
I claim that an object is stable when it _________________
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