Developing and Assessing Scientific Abilities

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Developing and Assessing Scientific Abilities

• Eugenia Etkina
• Graduate School of Education
• Rutgers University
• AAPT, Miami, Fl
• 2004
• http//paer.rutgers.edu/PT3

2
Assessing Student Achievement

• Alan Van Heuvelen
• Suzanne Brahmia, Marina Milner
• Sahana Murphy
• David Brookes, Michael Gentile, Aaron Warren,
• David Rosengrandt
• Julia Timofeeva
• Xueli Zou
• NSF ASA Program

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Outline

• What are scientific abilities?
• How do we help our students develop them?
• How do we know that the students are developing
  them?

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What are some scientific abilities?

• Ability to represent a process in multiple ways
• Ability to design an experimental investigation
  (an observational experiment a testing
  experiment an investigation to solve a problem)
• Ability to collect and analyze experimental data
• Ability to construct and modify explanations
• Ability to evaluate all of the above

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Formative assessment as a feedback tool

• Where do you need to go?
• Where are you now?
• What do you need to do to get there?

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Where can we use it?

• Lectures - electronic student response system
• Recitations - interactions with a TA
• Labs - exit interviews
• Homework - posted solutions
• Exams (summative)

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Multiple representation tasks

• Represent a process in multiple ways
• Extract information from a representation
• Move between representations
• Use representations to help solve problems

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Energy
The same situation is described with a bar chart
and in words. Which verbal description matches
this bar chart?
1 An object fell off a cliff and you measured it
having a large kinetic energy just before it hit
the ground. 2 A spring on a table top shot an
object vertically and you then measured the
kinetic energy of the object when it landed at
the height it was launched from on the table. 3
A spring shot an object vertically from a height
above the ground and then you measured the
kinetic energy at the ground level just before
the object hit the ground.
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Energy
A situation is represented pictorially below.
Which bar chart best matches the picture?
1
2
3
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Exam Problems

• A 100-kg fireman starts at rest and slides down a
  vertical pole. Assume that he was traveling at
  speed 6.0 m/s when he reached the floor. He
  managed to stop the center of his body in 0.4 m
  by bending his ankles and knees. What was the
  magnitude of the average force of the floor on
  his feet while stopping him?
• a) 4500 N b) 5500 N c) 600 N d) 1500 N
  e) 240 N

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Evaluation Tasks

• Evaluate MR
• Evaluate reasoning
• Evaluate a solution
• Evaluate experimental design

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Evaluate MR

• Marsha is pulling the front of a sled with a
  150-N force. The sled is on ice and its mass is
  45 kg (that includes the mass of her younger
  brother). The rope is at an angle of 20o with
  the ground. We assume that g 10 m/s2 10
  N/kg. Ignore all effects of friction.
• A student represented the situation
  mathematically
• x (150 N) (45 kg) ax
• y N (45 kg)(10 N/kg) (45 kg) 0
• Evaluate the above representation.

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Evaluate reasoning

• You and your friend are studying for a physics
  exam. Your friend claims that Newtons Second
  Law can be written as F ma. What do you think?
  How would you convince your friend of your
  opinion?
• .

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Evaluate a solution an exam question

• A 3.0 x104 N/m spring initially compressed 3.0 m
  launches a 300-kg cart on a frictionless level
  track. After traveling a short distance, the cart
  goes around a vertical loop of radius 5.0 m. You
  and your friend are asked to predict the force of
  the track on the cart as it passes the highest
  point of the loop. Your friend comes up with the
  following solution
• (1/2)kx02 (1/2)mv2 mgh
• or v2 (k/m)x02 - gh 850 m/s
• Ftrack on cart (mv2)/r 51,000N
• Evaluate your friends solution and correct
  mistakes if there are any.
• .

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Experimental design

• Design an observational experiment
• Design a testing experiment
• Design an investigation to solve a problem
• .

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Design observation experiment

• Design an experiment to determine if there is a
  relationship between pressure and temperature of
  air.
• Equipment Sealed hollow metal sphere ice, hot
  plate, thermometer, pressure gauge.
• a) Describe your experimental design. Include the
  following
• How will you vary the temperature? How will you
  measure it?
• How will you vary the pressure? How will you
  measure it?
• b) What other equipment do you need?
• c) Draw a labeled diagram of your experimental
  set-up.
• d) Record your observations in a table.
• e) What pattern did you find from your
  observations? What factors influenced the
  physical quantities you measured?
• f) Discuss whether your methods of measurement
  were reliable.

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Design testing experiment

• Your textbook says that if the temperature of a
  constant mass of gas is constant, the pressure
  and volume are inversely proportional to each
  other. Design an experiment to test this.
• Available Equipment Narrow glass tube (1m),
  putty or play dough, rulers, water.
• Write the following in your notebook
• a) Give an outline of your experimental design.
• b) Draw a labeled diagram of your experimental
  set-up.
• c) Fill out the following table with the
  arguments, prediction and evidence for testing
  your hypothesis.

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Design testing experiment

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Design an Investigation to Solve a Problem

• You have two aluminum foil bits on threads. You
  charge the bits by touching them with another
  charged object. Design an experiment to estimate
  the electric force that they exert on each other
  after being charged.
• Design an experiment to estimate their electric
  charge.

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Anomalous Data Tasks

• Scene Description
• The apparatus consists of a helium filled balloon
  that is tethered to the floor of a cart. The cart
  has clear plastic walls on its top and on all
  four sides. The cart is first quickly pushed to
  the left, and then quickly pulled to a stop.
  Predict what happens to the balloon. Explain why
  you made this prediction. Write down your
  explanation and prediction.
• Watch the experiments. Did the outcome match your
  prediction? Revise the explanation if necessary.

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Ability to Represent Information in Multiple Ways
rubric

• A student should be able to
• extract information from the representation
  correctly
• construct new representations from other
  representations
• evaluate the consistency of different
  representations and modify them when necessary
• use representations to solve problems

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Ability to Conduct an Observational Experiment
rubric

• A student should be able to
• describe what is observed without trying to
  explain
• decide what is to be measured
• identify independent and dependent variables
• find a pattern between the independent and
  dependent variables

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Ability to Conduct a Testing Experiment rubric

• A student should be able to
• identify a pattern or an explanation to test
• design a doable and meaningful experiment which
  tests the pattern/explanation
• use the pattern/explanation to make a physically
  reasonable prediction reasoning if/and/then
• identify and understand the significance of any
  additional assumptions made in making the
  prediction
• explain how the results of the experiment are
  related to the prediction and to the
  pattern/explanation reasoning but/therefore

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Ability to Design an Investigation to Solve a
Problem

• A student should be able to
• identify the goals of the investigation
• consider different approaches and decide which to
  use
• design several experiment to produce a meaningful
  answer and compare their results
• use equipment effectively
• identify shortcomings in an experimental design
  and propose useful modifications

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Ability to Collect and Analyze Experimental Data
rubric

• A student should be able to
• identify major sources of uncertainty in the
  experiments
• minimize experimental uncertainties record and
  represent data in a meaningful way
• make a judgment related to the patterns in the
  data (the presence of a pattern and the validity
  outliers, etc.)
• compare the results of multiple experiments and
  draw conclusions based on that comparison

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Ability to Construct and Modify Explanations
rubric

• A student should be able to
• simplify a situation and propose an explanation
  of the observed phenomenon using different types
  of reasoning analogical, contrasting,
  inductive, deductive
• judge the applicability of the explanation for
  more complex situations
• make reasonable predictions based on the
  explanation
• evaluate an explanation and modify it when
  necessary
• identify, evaluate, and address potential
  weaknesses of the explanation by checking its
  coherence with other models and its consistency
  with other relevant evidence

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What will we do next?

• improve the rubrics and use them to assess
  student work
• make a complete library of tasks
• write recommendations for instructors
• assemble all of the above into a book
• http//paer.rutgers.edu/PT3