Content Coverage

Phases of Water (and Matter), Physical Science, Cluster I (partial)

Water Cycle, Earth Science, Cluster VI (partial)
Concepts

Water, along with matter, has three phases (liquid, solid, and gas)

A molecular model of the three phases.

Heat and Pressure changes accompany phase changes (and other conditions).

Temperature remains the same at melting point, freezing point, and boiling point,
where at least two forms of water co-exist.

Examples of phase change in earth’s water cycle.

Conservation of matter (water) during all these changes.
Vocabulary

Phase, Liquid, Solid, Gas (and not Gasoline)

Molecule, Density, Energy

Melting, Freezing, Boiling, Condensation, Evaporation, and Sublimation

Physical Change
Assessments

Easy Items: Which of the following is a (liquid, solid, gas)?

Moderate Items: What makes something evaporate faster? What happens when
water is heated? Conservation of water.

Difficult Items: What happens to temperature during melting? Explain and draw
the FULL water cycle on Earth.
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Pretest
Lesson One
Goal
What do students already know?
Background Probing Questions (20 min)
1) What is matter? (anything that takes up space and has weight)
2) What are the forms of matter? (liquid, solid, gas)
3) What are the three forms of water?
4) How do water go from one form/phase/state to the other? (process: melt, freeze,
boil/evaporate)
Question Session Format
Classroom discussion, each student with pencil and sheet of paper to take notes. Write
down individual answers first, and then discuss.
Lesson Two
Goal
Explore conditions of phase change
Activity
Water Evaporation/Ice Melting (how fast can you make it happen)
Follow-up Questions
1) What makes water go from one phase to another? Specifically, what makes water
freeze? What makes ice melt? What makes water evaporate?
Activity
1) Water Evaporation (how fast can you make it happen)
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Lesson Three
Goal
Molecular Model of Water
Question
1) What happens to water when any of the above things happen? What doesn’t water
flow when it freezes? Where did water go when it evaporates? Why would water do
that?
Format
Generate several alterative proposals, evaluate them, see if they can explain all phase
changes, and introduce the molecular model.
Lesson Four
Goal
Molecular Model and Heat and Energy
Question
1) Do molecules move? Why do they move? How do they move?
2) Why does it take heat exchange to change phases?
3) (optional) What happens to temperature during freezing, melting, and boiling …
Activity
1) Human Chain? M&Ms?
2) Draw a flow diagram of heating/cooling changes, and evaluate whether the model
can explain all the phenomenon we already know.
Ice   Liquid Water   Vapor/Steam
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Lesson Five
Goal
Linking the water discussion so far to the earth’s water cycle, discuss what forms do phase
changes take on a grand scale, why, and under what conditions, and how water is conserved
and recycled.
Activity
Use the same map as Lesson Four, but now substantiate it with earth’s processes rather than
on the small scale.
Posttest
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BACKGROUND NOTES FROM WORKSHOP WEEK #2
LESSON COVERAGE
Physical Science, Cluster I, Phases of Matter and Physical Properties, included concepts:

Molecular explanations of solid, liquid, and gaseous states of matter

Relationship between temperature and volume, pressure and volume.

Concept of mixture, and solubility

Concept of density (mass and volume), and buoyancy
INITIAL STATE ASSESSMENT (paint a portrait of the average novice student)
What do students know? What don’t they know? What do we want them to know?

Terminologies
The average novice does not know certain terminologies, such as “phases”, “molecules”,
or “gas” (e.g., they may relate to gasoline instead). The novice does know about solids
and liquids.

Processes of Change
The average novice does know that water can turn into ice and vice versa. It is less clear
that they clearly understand water can turn into gas, much less that ice could go straight
to gas. The concept that many other substances (metal, air) in nature can also change
through the states is even further away (e.g., ice can’t be warmer than 0 degrees).

Boiling Point, Freezing Point, Melting Point
The average novice does understand boiling point. Freezing and melting point is less
clear. What happens to temperature during the freezing and melting processes is an
abstract and difficult concept to get across.

The Two Laws
The average novice does not know the two laws governing the relationship between
Pressure and Volume, and Temperature and Volume. They also need to understand that
temperature change (or heat exchange) accompanies phase changes.

Mixtures
The average novice does know about obvious mixtures (like a fruit salad) where it is clear
that the components are separable. But it is more difficult for them to imagine that salt
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water is a mixture. The concept of solubility is confused with concepts like
“disappearing” or “destroying”. The average novice does not understand that salt water
is a mixture at the molecular level.

Density
A potentially very difficult concept for students. They need to understand the things
occupying the same space can have different density. Buoyancy is a concept that
requires the understanding of density.
LESSON ACTIVITIES (the bag of tricks the teachers can use during
instruction)

Activities
-- Use ice cube in glass to demonstrate melting (observe the time it takes, the state it goes
into, and the temperature of the ice/water mixture and room temperature).
-- Breathe onto a mirror or pair of glasses, see the fog; imagine running nose freezing in
the winter. Highlight the idea that as gaseous vapor leaves the body (high temperature),
it condenses in the environment (low temperature).
-- Use hotplate to boil the water, see the steam.
-- Be a molecule, role-playing exercises using students as molecules.
-- Analogy: students in classroom (structured, solid), in hallway (fluid, liquid), on the
playground (no order, gaseous). Have students draw that match.
-- Freeze water, and ask why it no longer flows. Why a frozen water-gun no longer
squirt.
-- Use Styrofoam models to simulate models at the molecular and atomic level.

Discussions
Connection to real life examples: Bridge Expansion, Pothole formation, clothing (light
or dark) and relation to warmth. (note: this last topic may not deal directly with the
standards in this cluster)

Observations
Puddle evaporation.
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
Criterion for Selection
-- select based on intrinsic interest in the topic
-- select based on the “cool” effects, the surprise factor (students can’t predict outcome),
and something that targets misconceptions
-- select because it ties into real life experiences
-- two paths of selection: Select Favorite Activity ► Try to match it with some goals in
this unit, or Select the Goals in the unit ► Try to design an activity. Both takes place
and are valid approaches.

What to avoid
-- Any activity that would require rare materials (like dry ice)
-- Any activity that pose extreme expectations on part the teacher to manage the
classroom or to know the deep science behind it
-- Any activity that could only produce very subtle effects (e.g., like the vapor off ice
cubes, it is there, but not obvious)

Issues Yet to Be Explored
Instructional time, how long do we reasonably need to cover this content?
Instructional sequence, what activities go first, what goes second?
Assessment, to what extent do we integrate assessment into the instruction, instead of
using it as a post-quiz?
These three issues are not mutually exclusive. The interjection of assessment would
gauge how much “more” time is needed to achieve mastery. Well-sequenced activities
would improve the assessment results, thus reducing overall instructional time.
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LESSON PLAN UNIT A (Workshop #2)
Goals: Target the process of change from solid to liquid to water, and in reverse. Introduce a molecular
explanation of the phase changes.
Approach:
1) Use water to get into the idea of phases. Activities using ice cubes in glass, breathe
onto mirror or glasses, hotplate boiling, steam, freezer, etc. Help the students
understand how (at least in the instance of water), phase change can progress and
reverse. Highlight the importance of temperature change or heat exchange during
the transitions.
2) Develop a molecular understanding of phase changes. Use analogy of students
themselves (structured ► loosely connected) to describe the three states. Also can
use the idea of frozen watergun, and ask why it no longer moves.
3) Assessments: heating a test tube of water connected with a balloon, explain if & why
helium balloons expand under the sun. Insert assessment into instruction in a
formative dynamic manner.
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