Transcript 48x36 poster template - University of Cincinnati

Food for Thought
G. B.
1
1
Wickizer ,
D. Brock
Mechanical Engineering, University of Cincinnati, Cincinnati OH; 2 Simon Kenton High School, Independence, KY
Activity - Day 1
Abstract
Energy modeling was applied to food preparation on a daily basis in Independence, Kentucky
and in Playa Grande, Quiche, Guatemala. Students addressed the unique connection of
mankind to energy through food preparation and the societal impact of energy consumption.
This multicultural lesson required students to relate to examples from another culture and apply
the content to their own context through analogous examples. They engaged in career practices
used by some mechanical and chemical engineers to see how these professionals draw on
thermodynamics in their every-day activity. An impact analysis was conducted and an Impact
Vector Value assigned to this lesson. It was found that, while a majority of students
demonstrated mastery of the concepts, the impact of this lesson as measured by the Impact
Vector was about 20% of its maximum potential. Analysis of preliminary and post-delivery
assessments gave rise to revision of the assessment questions for clarity as well as suggesting
that students may benefit from review of the relationship of energy and force to better
understand the concept of work. Additionally, the lesson content could be more clearly related to
engineering careers and potential social impact by careful structuring.
Goals
1. The energy system will provide a STEM motif for this multidimensional energy lesson. Students
will learn the conceptual model of energy flow stemming from the First Law of Thermodynamics
and the relationship of enthalpy to the energy of systems and their surroundings.
2. They will interact with real world applications of this model to discover energy systems and their
surroundings. They will also understand how energy analysis is conducted by career
professionals such as chemical engineers, health scientists, and mechanical engineers and how
it relates to the food they eat and the water (or coffee) they drink.
3. In conjunction, students will be gaining exposure to global society through the themes of energy
flow and food.
Caffeine Initiation
• Coffee for the students made a catchy
introduction
• An exciting coffee pot provided the backdrop
for considering energy flow from a system to its
surroundings
• Students had to reconcile the conversion of heat
energy from a Bunsen
Burner into water motion
describing the latter as work
In the Guatemalan Kitchen
• Student-directed instruction
addressed the concepts and
vocabulary of the lesson by
applying them to food preparation in rural Guatemala
• An individual assignment
required students to re-apply
this content to their own
homes
• Review centered on the
relationship of energy forms
• The take-away question:
“What is the only system
which has no surroundings?”
Assessment Analysis
Vocabulary
energy – the ability to do work
system – a finite space, outside of which
are considered surroundings
chemical energy – energy in the form of
products or reactants owed to the attractive
forces responsible for bonds
energy source – a system which gives a
net output of energy
heat – energy transferred as a result of a
difference in temperature only
work – force applied over some
displacement (displacement is not exactly
the same as distance, remember?)
The meaning of “Impact Vector”
•Transformation and Tolerance
relate the potential for new content
learning, as students scoring highly
on the initial assessment stand to
gain less than other students
•Mastery and Misconception simply
show which concepts the students
are able to articulate following the
lesson
•Each data point represents one
students aggregate score
•1 point for Incorrect answers in the
initial case and Correct answers in
the final case and -1 point in the
opposite case
pressure-volume work – work done by a
system resulting in a change in pressure,
volume, or both pressure and volume
(abbreviate as “pv-work”)
Activity - Day 2
Objectives
1. Students will classify the components of a wood-burning oven system (typical of rural
Guatemala) and apply engineering vocabulary to an oven system typical of Independence,
Kentucky.
2. Students will differentiate energy transformations involving chemical reactions from those solely
based on physical transformations.
3. Students will analyze sources of error in a calorimetry test that estimates the energy content of
food substances (beans, rice, and corn), justifying their reasoning with the engineering concepts
of enthalpy change and the Law of Energy Conservation.
Results
• All four assessment questions were open ended
• Unexpected, alternate answers to assessment questions
were accepted as correct for 15% of the class, calling
the clarity of the assessment into question
• The presence of partially correct definitions of work
support the need to address the
relationship between energy and
force further
• The Impact Vector for this lesson
is valued at about 1, emphasizing
both positive results and room for
improvement in instructor/lesson
effectiveness
• 30% of the class (4 students)
showed overall improvement without
consideration of alternate answers
**Improvement does not equate to
mastery, it simply measures the
difference created by the lesson
US National Standards
From the AP Chemistry national definition:
“AP Chemistry should meet the objectives of a good college general chemistry course. Students in such a course should attain a depth of
understanding of fundamentals and a reasonable competence in dealing with chemical problems. The course should contribute to the development of
the students’ abilities to think clearly and to express their ideas, orally and in writing, with clarity and logic.”
Kentucky State Standards
SC-HS-1.1.8
Students will:
explain the importance of chemical reactions in a real-world context;
justify conclusions using evidence/data from chemical reactions.
Chemical reactions (e.g., acids and bases, oxidation, combustion of fuels, rusting, tarnishing) occur all around us and in every cell in our bodies.
These reactions may release or absorb energy.
SC-HS-4.6.1
Students will:
explain the relationships and connections between matter, energy, living systems and the physical environment;
give examples of conservation of matter and energy.
As matter and energy flow through different organizational levels (e.g., cells, organs, organisms, communities) and between living systems and the
physical environment, chemical elements are recombined in different ways. Each recombination results in storage and dissipation of energy into the
environment as heat. Matter and energy are conserved in each change.
•
•
•
•
MA-HS-2.2.1
Students will continue to apply to both real-world and mathematical problems U.S. customary and metric systems of measurement.
Students created “Energetic Tacos” in groups of three or four
Developed the need for enthalpy as an indicator of changes in system energy through group
discussion and review
Derived the classical definition of enthalpy with reference to vocabulary from Day 1
Demonstrated a Bunsen Burner as a chemical energy system and developed the parallels
between the reaction equation and the equation for enthalpy
Methane Redox Formula
CH4 + 2O2  CO2 + 2H2O
+
+
•
SC-HS-4.6.7
Students will:
explain real world applications of energy using information/data;
evaluate explanations of mechanical systems using current scientific knowledge about energy.
The universe becomes less orderly and less organized over time. Thus, the overall effect is that the energy is spread out uniformly. For example, in
the operation of mechanical systems, the useful energy output is always less than the energy input; the difference appears as heat.
MA-HS-5.3.3
Students will model, solve and graph first degree, two-variable equations and inequalities in real-world and mathematical problems.
are
•The vector information relates how
this particular lesson impacted
learning in this specific classroom
•The strength is about 20% of max.
Conclusions
Standards
Specific to this lesson are the following concepts:
First Law of Thermodynamics, conservation, system, surroundings, heat, work, pv work, Joules, Calories, state function, enthalpy
•Partially correct answers
scored with zero points
Visual comparison made to
Link the chemical equation
To enthalpy measurement
“Energy is neither created, nor destroyed”
System Energy Change = Total Energy Input +
Total Energy Output
How do we know this is true? What does this assume?
Enthalpy Change = Enthalpy Input + Enthalpy Output
Dh = Dhinput + Dhoutput
Dh = ( einput + pvinput )+ ( eoutput + pvoutput )
Dh = D (e + pv)
Reflections
•
•
•
Students need structuring to emphasize the career content and social impact of this lesson
A short hands-on activity would benefit the lecture portion of Day 2 and improve the concept
flow from the First Law of Thermodynamics
Setup time is intensive for Day 2; plan well in advance
1.
2.
3.
4.
5.
6.
Assessments for this lesson should be reviewed for clarity
Student concept mastery may not be directly related to the activity in some cases
The relationship between energy and force must be reviewed with the students
A majority of students mastered new content
The overall impact of this lesson is positive
Lesson content could be more clearly related to engineering careers and social impact by careful
structuring
References & Acknowledgments
Project STEP is funded through NSF Grant # DGE058532.
Thanks to Dr. Anant Kukreti, Dr. Daniel Oerther, Andrea Burrows
for their suggestions and support in the development, pilot, and review
of this lesson; to Dr. Raj Manglik and my friends at the Thermal Fluids
Laboratory for their new ideas and steady support; and to the brothers
and sisters of this year’s STEP family, who make the work a joy.
1. Silberberg, Martin. Chemistry: The Molecular Nature of Matter and
Change. McGraw-Hill, 5th ed. 2009
2. Talsma, Valerie. “Children’s Ideas in Science” October, 2008
http://www.cedu.niu.edu/scied/resources/sciencemisconceptions.htm