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 2
Effects of Temperature Change
on Solids, Liquids and Gases
Summary
Suggested Timeline
50 minutes
Materials
 Safety goggles for each student
 Station 1: Bunsen burner, bimetal
strip and/or ball and ring apparatus,
tongs to hold the strip, beaker of cold
water for cooling (if using ball and
ring apparatus)
 Station 2: 3 Petri dishes, one bottle of
food coloring, about 300 mL of hot
water, ice water (use bags of ice),
room temperature water, timer
 Station 3: hot plate with a metal tray
of water to act as a hot water bath,
250 mL Erlenmeyer flask, balloon
(that fits over end of the flask), ice
bucket or Styrofoam container (or
refrigerator if available)
Prep
1. Teacher sets up the nine setups (3
of each station).
2. Have a source of ice water and
hot water for station 2 students.
3. Place a balloon over each of the
three flasks for station 3 setups.
Students go to three different stations to test the effect of a
change in temperature on solids, liquids and gases. The solids are
bimetal strips and/or a ball and ring apparatus. They observe the
behavior of the strips and/or ball before and after heating over a
Bunsen burner.
The effect of temperature on liquids is observed in the behavior of
a drop of food coloring in three Petri dishes of water: one at room
temperature, one with ice water and one with hot water. The
effect of temperature on gases is observed in the expansion of a
balloon placed over the opening of a flask sitting in hot water, and
observing what happens to the balloon when placed on ice or in a
refrigerator.
Objective(s)
 Students discover that liquids and gases move faster at higher
temperatures and solids expand.
 They observe a demonstration that shows that there is no mass
increase when temperature increases
 They relate their observations back to the models of molecular
motion from the previous day’s probe to infer that the increase
in temperature causes an increase in the motion of the particles
in solids, liquids, and gases.
Teacher Background Knowledge
Teachers know the three states of matter and how molecular
motion differs among these states. Teacher needs to know how to
use a Bunsen burner.
This activity investigates how change in temperature relates to
molecular motion. The changes in temperature investigated are
not, in this case, sufficient to induce a phase change.
In a solid, the attractions between particles are so strong that the
particles are essentially fixed in place and can only vibrate (definite
shape and volume.) Adding heat increases the energy the particles
have to vibrate.
Phase Change Instructional Case
Lesson 2
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Lesson 2
Effects of Temperature Change
on Solids, Liquids and Gases
Teacher Background Knowledge (continued)
We observe this as an increase in temperature. The particles are
still strongly attracted to one another, so their average position
does not change, but the length of the vibration will increase,
leading to a potential expansion in the solid. The particles in a
liquid are still attracted to one another such that they remain in
constant contact with their neighbors but can freely move around
(shape of container, definite volume). The attractions between
particles in a gas are negligible; they can be thought of as entirely
independent from one another (shape and volume of container).
As such, in the case of liquids and gases, energy added as heat will
increase the kinetic energy of the particles. They will undergo the
same types of motion, but move more quickly than before. For
instance, this is seen in the faster dispersal of the food coloring in
the hot water.
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Lesson 2
Effects of Temperature Change
on Solids, Liquids and Gases
Standards 12
NGSS Performance Expectations:
This lesson supports students in progressing toward the NGSS Performance Expectation.
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
Developing and Using Models:
Reevaluate models (drawings) of
different phases used in Lesson 1
and have students confirm or
change their previous thinking of
the phenomena of phase
transition.
Use model of food coloring to
demonstrate phenomena of
motion of molecules as
temperature is affected.
1
Disciplinary Core Ideas
PS1.A: Structure and Properties
of Matter
The changes of state that occur
with variations in temperature or
pressure can be described and
predicted using these models of
matter.
Cross Cutting Concepts
Cause and Effect
Observe the changes that occur
when the water is cooled and
heated. Predict what will
happen when water is heated
and cooled.
Energy and Matter
Matter is conserved because
atoms are conserved in physical
and chemical processes. Note
that the masses are the same in
the demonstration when
comparing ice water and room
temperature water.
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 2
Effects of Temperature Change
on Solids, Liquids and Gases
In this lesson…
CCSS Mathematics
CCSS English-Language Arts
MP.2 Reason abstractly and quantitatively.
WHST 6-8 Support claim with logical reasoning
and relevant, accurate data and evidence that
demonstrate an understanding of phase
transition. Use models to investigate ideas about
increases or decreases in molecular motion. *Use
credible sources.
7.EE.B.4 Use variables to construct simple
inequalities to solve problems by reasoning about
the quantities regarding time in seconds for the
observation of food coloring.
Prior Knowledge
In grades K-2, students have learned that heating and cooling substances cause changes that are sometimes
reversible and sometimes not.
Students learned in the previous lesson that matter exists in moving particles and the freedom of movement
of these particles depends on the state of matter.
Lesson
Station 1:
1. Using bimetal strips: Students draw the strip on a data sheet before heating.
2. Students carefully heat the strip by using the tongs to pass the metal strip slowly back and forth through
the Bunsen burner flame and then make a drawing of the heated strip.
3. Have students place strip on lab bench to cool.
4. Draw the strip after cooling.
OR
1. Using ball and ring apparatus: Students attempt to pass the ball through the ring and describe
observations on a data sheet.
2. They heat the ball end by passing slowly back and forth through the flame and attempt to pass the ball
through the ring again. Describe observations on the data sheet.
3. Cool the ball in a beaker of cold water for a few minutes. Attempt to pass the ball through the ring again.
4. Describe observations on the data sheet.
Station 2:
1. Students set up 3 different Petri dishes one at a time:
 Cold water: ice-water from the teacher
 Room temperature water: from the tap
 Hot water: hot water from the teacher
2. As quickly as possible, add a drop of food coloring to the center of each Petri dish. Start the timer when
the drop of food coloring is added. Time how long it takes for the food coloring to reach the edge of the
dish for each temperature of water.
3. Observe the behavior of the food coloring, paying particular attention to any differences between the
three dishes.
4. Have students draw their observations and record the times on a data sheet.
Station 3:
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Lesson 2
Effects of Temperature Change
on Solids, Liquids and Gases
1. Make sure the flask is at room temperature. Note the placement of the balloon, and draw and describe
your observations.
2. Place the flask on ice or in a refrigerator for 5 minutes. Draw and describe your observations.
3. Place the flask in the hot water bath for 5 minutes. Draw and describe your observations.
Demonstration: Conservation of mass after an increase in temperature:
1. Find the mass of a container of water with ice water (with lid). Warm it to room temperature, and
determine the mass again.
2. Extend: Ask students to design an experiment to demonstrate the conservation of mass when room
temperature water is converted to a gas. Alternately, students can measure the mass of each phase,
demonstrating conservation of mass through physical phase changes.
Conclusion:
1. Refer back to the probe that you did yesterday. Which of the four models on the probe can explain the
behavior of all the materials that you observed today?
2. What evidence from the activities supports your choice?
3. In what way(s) does your evidence support your choice?
Potential Pitfalls
Students should be taught how to use a Bunsen burner prior to performing the activity.