P h a s e C h a n g e I n s t r uc ti o n a l C a s e : A s er i e s o f s t u de n t -c e nt er e d s c i e nc e l es s o ns
Lesson 6
Total Physical Response on
Phase Transition
Summary
In this lesson, the students work in groups to act out the different
states of matter and the processes of phase change.
Objective(s)
 Reinforce concepts of molecular motion in solids, liquids, and
gases and demonstrate an understanding of what molecular
changes take place during transitions between phases using
Total Physical Response.
Suggested Timeline
50 Minutes
Materials
 Tape
 Chalk
Prep
1. Ensure you have tape or chalk for
the students to delineate
boundaries.
Potential Pitfalls
Students may try to spread apart
during solid to liquid transition.
Remind them they may only change
shape and not increase the distance
between them. Students may attempt
to “ricochet” off one another during
the gas phase. Make sure they know
that physical contact is not permitted
in this simulation.
Teacher Background Knowledge
Teachers know the three states of matter and how molecular
motion differs among these states.
Solids are characterized by particles being essentially fixed in
positions close to one another that maximize their intermolecular
attractions. The particles are in motion, but the only motion
available to them is vibration. Below the melting point, increasing
temperature increases the vibrations. During melting, the particles
are able to break their intermolecular attractions and move more
freely as a liquid. Particles in a liquid maintain close contact with
one another but are able to move translationally. Increasing the
temperature of a liquid increases the speed at which they are able
to move. Increasing the temperature to the boiling point provides
sufficient heat to break intermolecular attractions entirely,
allowing particles to become independent gas particles that will
move throughout any volume available. Increasing the
temperature of a gas increases the speed at which the gas particles
move. As temperature is decreased, the particles slow down and
have less energy to overcome their intermolecular attractions,
ultimately changing from a gas to a liquid to a solid.
.
Phase Change Instructional Case
Lesson 6
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Lesson 6 Total Physical Response on Phase
Transition
Standards 12
NGSS Performance Expectations
MS-PS 1-4: Develop a model that predicts and describes changes in particle motion,
temperature, and state of a pure substance when thermal energy is added or removed.
Emphasis is on qualitative molecular-level models of solids, liquids, and gases to show that
adding or removing thermal energy increases or decreases kinetic energy of the particles until a
change of state occurs. Examples of models could include drawings and diagrams. Examples of
particles could include molecules or inert atoms. Examples of pure substances could include
water, carbon dioxide, and helium.
MS-PS 1-5: Develop and use a model to describe how the total number of atoms does not
change in a chemical reaction and thus mass is conserved.
Emphasis is on law of conservation of matter and on physical models or drawings, including
digital forms that represent atoms.
Assessment Boundaries: Assessment does not include the use of atomic masses, balancing
symbolic equations, or intermolecular forces.
In this lesson…
Science and Engineering
Practices
Disciplinary Core Ideas
Cross Cutting Concepts
Analyzing and Interpreting
Data: Analyze and interpret
qualitative observations on
phase change and
quantitative observations
(temperature and time) to
provide evidence for
phenomena of phase
change. Use graphical
displays of data set to
identify relationships.
PS1.A: Structure and Properties
of Matter
Gases and liquids are made of
molecules or inert atoms that are
moving about relative to each
other. In a liquid, the molecules
are constantly in contact with
others; in a gas, they are widely
spaced except when they happen
to collide. In a solid, atoms are
closely spaced and may vibrate in
position but do not change
relative locations. The changes of
state that occur with variations in
temperature or pressure can be
described and predicted using
these models of matter.
Cause and Effect
Observe causal relationship
of temperature increase and
phase change. Use
experimental data as
empirical evidence to
support predictions on
various phase changes.
1
Energy and Matter
Matter is conserved because
atoms are conserved in a
physical change. As the
molecules are heated, the
transfer of energy drives the
phase transition.
NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, D.C.: The
National Academies Press.
2
National Governors Association Center for Best Practices, Council of Chief State School Officers Title: Common
Core State Standards (insert specific content area if you are using only one) Publisher: National Governors
Association Center for Best Practices, Council of Chief State School Officers, Washington D.C. Copyright Date: 2010
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Lesson 6 Total Physical Response on Phase
Transition
In this lesson…
CCSS Mathematics
n/a
CCSS English-Language Arts
SL.8.1 Engage effectively in a range of
collaborative discussions (one-on-one, in
groups, and teacher-led) with diverse partners
on grade 8 topics, texts, and issues, building on
others’ ideas and expressing their own clearly
Prior Knowledge
In grades 3-5, students have learned that matter is always conserved even if it seems to disappear.
Measurements of a variety of observable properties can be used to identify particular materials.
Students learned in the previous lesson the relationship between the graphical representation of
temperature versus time and how it relates to phase change based on a previous probe.
Lesson
1. Separate class into groups of 6 in a spacious area. Each group should have a contained area in which
to perform, using tape, chalk, or natural boundaries.
2. Tell students that they are going to take on the role of a molecule. Ask students to think about how
they might represent a solid, a liquid, and a gas. If students need help, offer the following
suggestions:

Solid: students should be almost touching one another and vibrating or wiggling slightly.

Liquid: students should move among each other as closely as they were in a solid – there
should be no visible change in volume.

Gas: students should move apart, fully exploring the contained area.
3. Allow students time to practice each phase.
4. Tell students that there is going to be a change in temperature and they have to respond
accordingly.
5. Have students begin as solid and tell them it is getting hot. The teacher should explicitly state when
melting point and boiling point are reached. They should respond by moving faster and moving
around and throughout the same amount of space. Continue changing temperature until they have
performed all phase changes.
 Challenge: Ask students how they might demonstrate the difference between boiling and
evaporation. Students must explain their reasoning with each movement.
6. Teacher entries to increase critical thinking:




What takes the most energy? (sublimation – going from standing directly to running)
What phase allows the most movement?
Which changes needed an increase in energy? When you were given the energy to change
phase was this endothermic or exothermic?
How are thermal energy and temperature similar? Different?