Full of Hot Air
Objectives
By the end of this lesson, students should be able to…
 Cognitive
o Differentiate between different variables used to calculate
changes in heat
o State what each variable stands for in the expression used to
calculate heat, and enthalpy changes
o Evaluate expressions used to calculate values for heat
o Explore how heat flows from one substance to another
 Psychomoter
o Calculate values for specific heat, heat, and change in
temperature
o Control variables in experiments used to determine values for
heat, specific heat, and heat capacity
o Measure change in temperature to determine specific heat of
substance
o Classify reactions as exothermic or endothermic
o Graph changes in temperature as a function of time
 Analyze this graphical data to determine change in
temperature
 Affective
o Display objectivity
o Show willingness to change
o Show thoroughness in work
Standards
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Process Standards:
o 11-12.RS.1 Cite specific textual evidence to support analysis of science,
attending to important distinctions the author makes and to any gaps or
inconsistencies in the account.
o 11-12.RS.3 Follow precisely a complex multistep procedure when
carrying out experiments or taking measurements; analyze the specific
results based on explanations in the text.
o 11-12.RS.4 Determine the meaning of symbols, key terms, and other
domain-specific words and phrases as they are used in a specific
scientific context relevant to grades 11-12 texts and topics.
o 11-12.RS.8 Evaluate the hypotheses, data, analysis, and conclusions
in a science text, verifying the data when possible and corroborating or
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challenging conclusions with other sources of information.
11-12.RS.9 Synthesize information from a range of sources (e.g., texts,
experiments, simulations) into a coherent understanding of a process,
phenomenon, or concept, resolving conflicting information when
possible.
11-12.WS.1 Write arguments focused on discipline-specific content.
 Develop claim(s) and counterclaims fairly and thoroughly,
supplying the most relevant data and evidence for each while
pointing out the strengths and limitations of both claim(s) and
counterclaims in a discipline-appropriate form that anticipates
the audience’s knowledge level, concerns, values, and possible
biases.
 Establish and maintain a formal style and objective tone while
attending to the norms and conventions of the discipline in
which they are writing.
 Provide a concluding statement or section that follows from or
supports the argument presented.
11-12.WS.2 Write informative/explanatory texts, including scientific
procedures/ experiments.
 Develop the topic thoroughly by selecting the most significant
and relevant facts, extended definitions, concrete details,
quotations, or other information and examples appropriate to
the audience’s knowledge of the topic.
 Use varied transitions and sentence structures to link the major
sections of the text, create cohesion, and clarify the
relationships among complex ideas and concepts.
 Use precise language, domain-specific vocabulary and
techniques such as metaphor, simile, and analogy to manage
the complexity of the topic; convey a knowledgeable stance in
a style that responds to the discipline and context as well as to
the expertise of likely readers.
 Provide a concluding statement or section that follows from and
supports the information or explanation provided (e.g.,
articulating implications or the significance of the topic).
11-12.WS.7 Conduct short as well as more sustained research
projects to answer a question (including a self-generated question) or
solve a problem; narrow or broaden the inquiry when appropriate;
synthesize multiple sources on the subject, demonstrating
understanding of the subject under investigation.
11-12.WS.8 Gather relevant information from multiple authoritative
print and digital sources, using advanced searches effectively; assess
the strengths and limitations of each source in terms of the specific
task, purpose, and audience; integrate information into the text
selectivity to maintain the flow of ideas, avoiding plagiarism and
overreliance on any once source and following a standard format for
citation.
11-12.WS.9 Draw evidence from informational texts to support
analysis, reflection, and research.
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Content Standards:
o C.6.1 Explain that atoms and molecules are in constant motion and
that this motion increases as thermal energy increases.
o C.6.2 Distinguish between the concepts of temperature and heat flow
in macroscopic and microscopic terms.
o C.6.3 Classify chemical reactions and phase changes as exothermic
or endothermic.
o C.6.4 Solve problems involving heat flow and temperature changes by
using known values of specific heat, phase change constants (i.e., latent
heat values) or both.
Core Standards:
o Recognize that chemical reactions result in either the release or
absorption of energy. (C.6.1, C.6.2, C.6.3)
o Apply the law of conservation of energy. (C.6.4)
Misconceptions
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Heat has the properties of matter or substance
Collisions between molecules cause heat
Heat can add weight to the object being heated
Heat is a substance residing in a body, which can pass from one body to
another, like a fluid.
Heat is in the fuel being burned and is not formed during combustion
Heat is something that heats up other things; either the hot object or a
substance given off by it
Heat is a sensation
The state of hotness or coldness depends on the material from which a body
is made
Heating a body always means raising its temperature
Temperature is a measure of a body’s heat
Heat is conserved
Heat is not energy
Heat is not a measureable quantifiable concept.
Safety Considerations
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Methane gas will be ignited.
o An appropriate distance between students and instructor should be
used.
o Be sure to know the location of the fire blanket and fire extinguisher.
o Be sure to wear goggles.
A Bunsen burner will be utilized to burst a balloon. Be sure to keep exposed
skin way from the flame.
Materials
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Five Styrofoam cups
Distilled water
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Graduated cylinder
Gloves
Scissors
Instant cold packs containing ammonium nitrate and water
Beaker
Metal spatula
Digital thermometer, Vernier
Vernier interface
Computer
Unknown metal (given by the instructor for the elaboration phase)
Bunsen burner
Methane gas (likely from gas line in lab)
Water and soap solution
Rubber hose
Matches
Magnesium turnings
.1 M sodium hydroxide
.1 M hydrochloric acid
.1 M sulfuric acid
Engagement
Every student will start out this lesson by filling out his or her respective
journal or completing the attached student handout sheet about the following
demonstration. The demonstration starts off with the instructor filling two balloons
with air. One of these balloons will contain a small amount of water which should
not exceed 50 mL. The instructor will present both of these balloons to the class.
After lighting the Bunsen burner, the instructor will ask the students to record what
they think will happen to the balloon if held up to the flame. Students will hopefully
note that the balloon will burst from their previous experiences with balloons and
flames. The instructor should then hold the balloon over the flame, and the balloon
should burst very quickly.
After demonstrating the balloon will burst with just air, the instructor will show
the balloon with water to the students. The instructor will ask the students to write
down what he or she thinks will happen if held to the flame. The instructor will then
hold the balloon in such a manner that the water in the balloon will be directly in the
flame when the balloon is lowered closer to the flame. Students will observe that
this balloon doesn’t burst.
The instructor can then introduce students to terms related to this lesson,
such as heat, temperature, and specific heat. The instructor doesn’t have to give
long explanations into these terms. The instructor can let students know that the
balloon doesn’t burst in this case because the water in the balloon has a higher
specific heat than air.
To demonstrate the higher specific heat of water than most other substances,
the instructor can ignite methane bubbles in his or her hand. The instructor should
get a solution of soap and water together. The instructor should then bubble the
methane through to get large bubbles to form. The instructor should then fully
emerge his or her hands into the soap water solution. Then the instructor should
scoop up the bubbles with one hand. The instructor will then light the bubbles on fire
with either a butane lighter or match with the other hand. The instructor will be left
unharmed from the process. It is important to tell the students to stay far away in
case something goes wrong.
Exploration
The students should complete the attached activity entitled Cold Pack
Chemistry. This experiment will introduce students to reactions that cause a change
in temperature. Through completing the laboratory experiment, the students will be
introduced to calculations involving determining heat exchanges between water and
other substances.
Explanation
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Thermochemistry
Energy
In this topic, we are interested in energy transfers
 Types of energy
 Definition: energy is the capacity to do work
 Kinetic energy
 Energy produced by a moving object
 Potential energy
 Energy available due to objects position
 Radiant energy
 Solar energy
 Chemical energy
 Energy stored within chemical substances
 Thermal energy
 Energy associated with the random motion of particles
and atoms
 We are interested in thermal energy for this topic
Conservation of Energy
Different forms of energy can be converted into other forms of energy
 For example: a ball rolling down a hill converts its potential energy
into kinetic energy.
Through careful analysis, scientists have determined that the total energy of a
system must be conserved.
 This means that energy cannot be created or destroyed by any
process. But energy can be interconverted from one form to another.
 This also means that the energy of the universe must be held
constant.
Thermochemistry
Thermochemistry is the study of heat change in chemical reactions.
 Heat is the transfer of thermal energy between two bodies that are at
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different temperatures.
 To use thermochemistry we need to define our system and
surroundings.
 The system is the part of the universe we are interested in
studying.
 The system can be open, closed, or isolated.
 An open system allows for mass and energy to
transfer.
 A closed system allows for energy to transfer but
not mass.
 An isolated system will not allow mass nor
energy to transfer.
 The surroundings are everything else.
Chemical processes
A chemical process can be either endothermic or exothermic.
 An endothermic process is a process in which heat has to be supplied
to the system in order for the reaction to proceed.
 An exothermic process is a process in which heat is released by the
system when the reaction proceeds.
Thermodynamics
Thermochemistry is a subtopic in the much broader area of thermodynamics.
 Thermodynamics is interested in studying changes in the state of a
system.
 States of a system are the values for all of the relevant
macroscopic properties
 Examples: composition, energy, temperature, pressure, and
volume.
 Thermodynamics is governed by four laws.
 For our topic though, we are only interested in the first law
The First Law
The first law of thermodynamics is basically a restatement of the conservation
of mass.
 States that the energy gained or given off by the system must be
absorbed or given off to the surroundings.
 Can be rewritten to give ΔE=q + w.
 q is the symbol for the heat
 q=msΔT
 m is mass
 s is specific heat
 ΔT is the change in temperature
 w is the symbol for work
 w=F x d
 F is the force and d is the distance that force is
applied
For next time
We will talk about enthalpy changes
 How to calculate them
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 What they stand for
Calorimetry
 Constant volume
 Constant pressure
 What each of these calculate
Elaboration
The students will be responsible for designing and carrying out experiments
with a partner to measure the specific heat of a hot metal. The students will have
the same supplies available as they had available in the exploration activity. The
instructor should approve every group’s procedure for their respective experiments.
The instructor should be certain to ascertain whether the procedure provided will
give a good measure for the specific heat of a substance.
Each student group should then prepare a lab report following the guidelines
set forth in the attached rubric. Each paper should have an introduction which
introduces the reasoning and theory behind the experiment, an experimental
producedure section which details every step taken, a results section that shows all
of the data collected, and a results section that details how the data was used to
calculate the final result.
Evaluation
The students will be evaluated over the completion of the laboratory report
done in the elaboration stage according to the rubric provided. Instructors should
also note that there are many opportunities for informal evaluations, which can be
done during the laboratory parts of the exploration and elaboration stages along with
checking for understanding of material during the explanation phase.
Discussion Questions & Answers
1. What is a type of transformation between one form of energy to another?
a. Potential to kinetic, chemical to thermal, and many other possible
2. What factors affect the amount of heat an object has?
a. Mass, specific heat of substance, and the temperature change
3. Why didn’t the balloon burst when water was inside the balloon?
a. The water has a higher specific heat than the gas in the balloon, which
means that the water will absorb more heat than the gas. This causes
the gas to not expand much at all and will not pop the balloon.
4. Why didn’t the instructor get hurt when igniting the methane bubbles?
a. The water that the instructor dipped his or her hand into before
scooping up the bubbles has a higher specific heat than the skin,
which means that the water will absorb most of the heat from the
burning of the methane, bubbles.
References
Chang, R. (2010). Chemistry (10th ed.) New York, NY: McGraw-Hill.
Evans, C. (2004). Learning with inquiring minds. The Science Teacher, 71(1), 27-30.
Retrived from http://www.nsta.org.
Garland, C. W., Nibler J. W., & Shoemaker D. P. (2009). Experiments in physical
chemistry (8th ed.) New York, NY: McGraw-Hill
Royal Society of Chemistry. (2008, October 29). Exothermic or endothermic?
Retrieved from http://www.rsc.org/learnchemistry/resource/res00000740/exothermic-or-endothermic
Whyte, D. B. (2013, January 10). Cold pack chemistry: Where does the heat go?
Retrieved from http://www.sciencebuddies.org/science-fairprojects/project_ideas/Chem_p081.shtml#summary