Transcript Slide 1

What is a “Performance Task?”
An assessment exercise that is goal directed. The
exercise is developed to elicit students' application of a
wide range of skills and knowledge to solve a complex
problem.
Why are we doing this?
1) The core goals of the new PISD curriculum program
mandate it! (Specifically the science “transfer
goals” which reflect the graduate profile.
2) Because it will stretch you beyond a paper and
pencil test.
Is this something new?
Not really. Every lab exercise in this class that hasn’t
been a discovery activity has been a performance
assessment of some kind. Your catapult project was a
performance assessment, but more provided more
structure and direction than this activity.
What is the task?
Design a quantitative experiment to test the
effectiveness of different insulation materials against
radiant and/or conductive heat transfer.
•You may consider not only “household insulators” like
fiberglass, cellulose, different kinds of foam, bubble wrap,
reflective film, drywall, housewrap, etc., but also different
materials and varieties of clothing.
•You should not compare household insulation to clothing as
that would not be a valid, useful comparison in this context.
•More details in written handout.
This task will:
• Count as your major, summative assessment for
this unit of study.
• Require that you think like a scientist.
• Force you to think creatively on your own and
communicate with your peers.
• Apply good scientific methodology.
• Communicate your ideas and results in a formal
way.
• Connect your scientific conclusions to the real
world through a cost-benefit analysis.
Structure of the project
• Must work in groups (2-3) from the same class
– Siblings exempted from same class requirement
•
•
•
•
•
•
•
Proper lab reporting format at all stages
Realistically testable
Probably needs a “control” variable, possibly several
Must provide quantitative data
Must compare at least 4 different materials
Must have at least 10 different data sets
Your experiment cannot be the same as another
group’s. Keep your ideas private or both groups will be
asked to re-write.
What you will turn in and when
• Complete experimental outline draft
– (Purpose, Theory, Procedure)
– 1/28, instructor review, student revise as needed
• Final experimental draft
– (Purpose, Theory, Procedure)
– 1/30, instructor check for completion/revisions
• Final complete lab report w/ cost analysis
– 2/6 by the end of class
– Time in class to work/write 2/4 & 2/5, bring
experimental elements to perform trials if desired
Project Rubric:
First draft of purpose/theory/procedure:
Content (5 pts)
Quality and Technique (5 pts)
Final draft of purpose/theory/procedure:
Content (5 pts)
Quality and Technique (5 pts)
_____
_____
_____
_____
Lab report: (60 pts—see below)
_____
Cost-Benefit analysis: (20 pts)
_____
Final Score (100 pts total)
_____
Lab Report (60%):(Each point below is equal to 4% of project grade)
Purpose and Theory:
____ / 4
Procedure:
____ / 1-2 (see next item)
Schematic w/ dimensions:
____ / 1 (if needed)
(only needed if custom materials are used)
Data collected:
____ / 3
Analysis/Calculations:
____ / 3
(includes any charts, tables, graphs created AND a sample of every type of calculation performed)
Conclusions w/ error discussion:
____ / 3
(a good conclusion might also include a discussion of extension to your experiment, how it could be improved upon or elaborated
to work with additional variables, including future work suggested by your results)
YOU MUST KEEP YOUR RUBRIC TO TURN IN
WITH YOUR LAB REPORT. IF YOU LOSE THE
GRADED COPY FROM THE SCORING OF
YOUR FIRST DRAFT YOU WILL LOSE THOSE
POINTS!
Cost-Benefit Analysis
• To provide a basis for comparing projects. It
involves comparing the total expected cost of
each option against the total expected benefits,
to see whether the benefits outweigh the costs,
and by how much.
• You must determine how to logically normalize
costs in your experiment so that you are
comparing apples to apples.
• You must determine, on the basis of your data
which material, in which arrangement provides
the best insulation at the lowest cost.
CBA (cont’d)
• Attached to your final lab report, but as a
separate document, basically a new page(s)
• This analysis will include both math and verbal
explanations of your findings, and may include
graphics that may help explain the comparisons
made.
• No specific format is mandated, but it is
encouraged that the paper product that you turn
in be appropriate for a professional report.
• Be creative, but be mathematically appropriate.
CBA Example
• If you compared foam board to fiberglass to
cellulose your cost-benefit analysis might look at
the effectiveness of the product per inch of
thickness per square foot of product, and then
compared that result to the cost of the material
in that arrangement.
• Similarly, for clothing you might compare the
effectiveness of X number of layers/thickness of
fabric to the cost per square foot of the garment
or fabric.
Costs to you
• Consider pooling resources with several groups
so that no student spends more than a few
dollars on materials.
• Consider using materials that you may already
own
– Insulation could be removed from attic spaces, tested
and replaced (unless you cut it up)
– Clothing you already own might be used (unless you
cut it up)
• Students experiencing financial hardship should
speak to me in confidence. Discrete
arrangements can be easily made.
SAFETY!
• Please review the paper handout for specific
safety tips and experimental ideas.
• Many insulating materials burn or melt under
the right conditions. Open flames are
discouraged and radiant heat sources should
be used with the utmost care and caution.
• Clear any procedures performed at home with
your parents or a supervising adult.
• Unsafe experimental designs will lose points!
More safety issues
• Many home insulation products are skin
irritants and can be an inhalation hazard.
• Wear appropriate clothing, hand and eye
protection when using these materials.
• Read all labels carefully and MSDS sheets if
available.
• Research safe handling procedures online
from reputable sources prior to use.
Take care with water
• Wet materials often have different thermal
properties than the same product when dry.
• Be sure any experiment using hot/cold water
and/or ice protects the insulating material
from dampness and that this control is
incorporated into your procedure for all
substances tests, or any deviations
acknowledged in your report.