LESSON 6: Dew Drops
ESTIMATED TIME Setup: 5–10 minutes | Procedure: 15–20 minutes
• DESCRIPTION
• MATERIALS
Use jars of hot and cold water to demonstrate how
water changes states.
Clear glass jars with lids
Ice
o Hot and cold water
o
o
• OBJECTIVE
This lesson demonstrates the physical change of a
gas to a liquid and the conditions under which it
occurs. Students place hot and ice-cold water in
different jars to observe condensation. This lesson
can be extended to address elements, compounds,
energy, and energy transfer.
Always remember to use the appropriate safety
equipment when conducting your experiment.
Refer to the Safety First section in the Resource Guide
on pages 391–393 for more detailed information about
safety in the classroom.
Jump ahead to page 80 to view the
Experimental Procedure.
• CONTENT TOPICS
Scientific inquiry; states of matter; physical changes
(condensation, vaporization); atomic structure; energy
NATIONAL SCIENCE EDUCATION STANDARDS SUBJECT MATTER
This lesson applies both Dimension 1: Scientific and Engineering Practices and Dimension 2: Crosscutting Concepts
from “A Framework for K–12 Science Education,” established as a guide for the updated National Science Education
Standards. In addition, this lesson covers the following Disciplinary Core Ideas from that framework:
• PS1.A: Structure and Properties of Matter
• PS3.A: Definitions of Energy
• PS3.B: Conversion of Energy and Energy Transfer
• PS3.D: Energy in Chemical Processes and Everyday Life
OBSERVATION & RESEARCH
BACKGROUND
Scientists use the term matter to describe the things
around you. Matter is anything that has mass and takes
up space, such as paper, food, cups, and water. Matter
exists primarily in three states on the earth—solid,
liquid, and gas. Solids have a definite volume and a
definite shape. Examples of solids are chairs, books,
and cups. Liquids have a definite volume but no definite
shape. Therefore, they will take the shape of the vessel
that contains them, filling the bottom of the container
first. Examples of liquids are water and orange juice.
Gases have no definite volume and no definite shape.
If a gas is put into a container, it will take the shape of
the container, filling that container completely. An
example of a gas is the air around you! In addition to
differences in shape and volume, solids, liquids, and
gases have other unique properties.
Changes between these states of matter are physical
changes. A physical change is any change in a
substance’s form that does not change its chemical
makeup. The chemical formula of the substance stays
the same before and after the change. For example, ice,
water, and water vapor are all H2O in different physical
states. The chemical formula remains H2O regardless of
whether it is in the solid, liquid, or gaseous state.
Matter can change from one state to another, generally as
a result of a change in temperature. Melting is a change
in state from a solid to a liquid. The opposite change is
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LESSON 6: Dew Drops
freezing. Freezing is a change in state from a liquid to a
solid. A change in state from a liquid to a gas is known
as vaporization, while a change in state from a gas to a
liquid is known as condensation. Changes directly
between the solid and gaseous states that do not go
through the liquid state first are less common.
Sublimation is a change in state from a solid directly to
a gas. The opposite is deposition, in which a gas changes
directly into a solid.
In this experiment, water is used to demonstrate the
physical changes between a liquid and a gas. The gas is
water vapor, which occurs naturally in the air. When the
water vapor comes in contact with the cool glass, the
water vapor cools and changes into liquid water. The jar
with ice water makes the glass jar very cold. Because
there is water vapor in the outside air, as the water vapor
in the outside air touches the cold glass, the vapor
becomes a liquid. As a result, you can see droplets of
water form on the outside of the glass jar. The jar
holding the hot water acts in a similar way; however,
the vapor inside the jar comes in contact with the cooler
glass. Therefore, the water droplets will form inside the
jar. (If the water is hot enough, students may also be able
to first observe vaporization.)
FORMULAS & EQUATIONS
Tap water is actually a mixture of pure water, minerals,
and other substances.
Keep in mind, enough energy has to be added to cause
this change. The temperature of the liquid substance
must reach its boiling point. The boiling point is the
temperature at which a substance begins changing its
state from a liquid to a gas.
On the other hand, when energy is removed from a gas,
the gas changes into liquid form, and it condenses.
CONNECT TO THE YOU BE THE
CHEMIST CHALLENGE
For additional background information, please
review CEF’s Challenge study materials online at
http://www.chemed.org/ybtc/challenge/study.aspx.
• Additional information on physical changes and
states of matter can be found in the Classification
of Matter section of CEF’s Passport to Science
Exploration: The Core of Chemistry.
HYPOTHESIS
uWater droplets will form on the inside
of a glass jar filled with hot water, and water
droplets will form on the outside of a glass jar filled
with ice water because of temperature differences.
The chemical formula for pure water, in any state of
matter, is H2O.
During a physical change, the structure or chemical
formula of the substance does not change. As energy
(in the form of thermal energy) is added to or removed
from the substance, it changes from one state of matter
to another.
Fun Fact
When you take a hot shower,
When enough energy is added to liquid water, it becomes
a gas.
H2O (l) + energy g H2O (g)
the mirror or bathroom window
usually gets foggy. The “fog” is
actually the condensation of
water vapor.
You Be The Chemist® Activity Guide | page 78
LESSON 6: Dew Drops
DIFFERENTIATION IN THE CLASSROOM
LOWER GRADE LEVELS/BEGINNERS
Perform the experiment as described on page 80, but spend
more time on states of matter. Show pictures of different
things and have the students identify the state of matter.
Likewise, show images of matter changing states—ice
melting, water droplets forming on grass, etc. (You may
need to use a series of images to demonstrate the changes.)
Again, have the students identify which change they see
and how they know.
HIGHER GRADE LEVELS/ADVANCED STUDENTS
DESCRIPTION
Jars of hot and cold water are used to demonstrate the
processes of condensation and energy transfer.
OBJECTIVE
This lesson demonstrates energy transfer, condensation,
and the conditions under which condensation occurs.
OBSERVATION & RESEARCH
Matter can be classified into pure substances and mixtures.
Elements are pure substances that cannot be broken down
further by normal chemical means. All matter is made up of
basic elements. They are known as the building blocks of
matter. A compound is a pure substance made up of two or
more elements joined in a defined ratio. For example, water
is a compound made up of the elements hydrogen and
oxygen in a 2:1 ratio. Two hydrogen atoms and one oxygen
atom join together, giving water the chemical formula H2O.
However, the water that comes out of a sink is not a pure
substance. It is a mixture of pure water, minerals, and other
substances. It is generally called tap water.
Matter exists primarily in three states on the earth—solid,
liquid, or gas. Solids, such as books and cups, have a
definite volume and a definite shape. Liquids, such as
water and orange juice, have a definite volume but no
definite shape. Gases, such as the air around you, have no
definite volume and no definite shape. Changes between
these states of matter are physical changes. A physical
change is any change in a substance’s form that does not
change its chemical makeup. For example, ice, water,
and water vapor are all H2O in different physical states.
The chemical formula remains H2O regardless of whether
it is in the solid, liquid, or gaseous state.
Matter changes states whenever energy is added or taken
away. Energy is a measure of the ability to do work or
generate heat. During a change in state, energy is
transferred between a substance and its surroundings.
These changes are often the result of changes in
temperature. When a solid gains enough energy, it melts
into liquid form. Likewise, when a liquid gains enough
energy, it vaporizes to become a gas. If a gas loses enough
energy, it will condense and become a liquid. If a liquid
loses enough energy, it will freeze into solid form.
In this experiment, water is used to demonstrate the
physical changes between a liquid and a gas as energy is
transferred between the water (H2O) and its surroundings.
The gaseous form of H2O is water vapor, which occurs
naturally in the air. When the water vapor comes in contact
with the cool glass, the water vapor cools and changes into
liquid water.
The jar with ice water makes the glass jar very cold.
Because there is water vapor in the outside air, as water
vapor in the outside air touches the cold glass, the vapor
becomes a liquid. As a result, you can see droplets of water
form on the outside of the glass jar. The jar holding the hot
water acts in a similar way; however, the vapor inside the
jar comes in contact with the cooler glass. Therefore, the
water droplets will form inside the jar. (If the water is hot
enough, students may also be able to first observe
vaporization.)
CONNECT TO THE YOU BE THE
CHEMIST CHALLENGE
For additional background information, please
review CEF’s Challenge study materials online at
http://www.chemed.org/ybtc/challenge/study.aspx.
• Additional information on states of matter, physical
changes, and energy changes can be found in the
Classification of Matter section of CEF’s Passport to
Science Exploration: The Core of Chemistry.
• Additional information on energy can be found in
the Measurement section of CEF’s Passport to
Science Exploration: The Core of Chemistry.
• Additional information on elements and
compounds can be found in the Atomic Structure
section of CEF’s Passport to Science Exploration:
The Core of Chemistry.
You Be The Chemist® Activity Guide | page 79
LESSON 6: Dew Drops
EXPERIMENTATION
As the students perform the experiment, challenge them
to identify the independent, dependent, and controlled
variables, as well as whether there is a control setup for the
experiment. (Hint: If the temperature of the water in the
jar changes, will the water droplets form in a different
location?) Review the information in the Scientific Inquiry
section on pages 14–16 to discuss variables.
NOTES
EXPERIMENTAL PROCEDURE
Part One
1. Add hot tap water to a jar until it is half full.
2. Put the lid on the jar, and place it on a table.
Observe.
3. Pour the water out of the jar, and dry the inside
and outside of the jar completely.
Part Two
1. Add cold tap water to a jar until it is half full.
Then, add a few ice cubes to make the water
very cold.
2. Put the lid on the jar, and place the jar on a table.
Observe.
In the cold water setup, if you do not see any
water droplets forming on the jar, try the
experiment in a bathroom, kitchen, or another humid
room where the outside air may have more water
molecules in it.
DATA COLLECTION
Have students record data in their science notebooks or
on the following activity sheet. What forms on the inside or
outside of the jar? Have students answer the questions on
the activity sheet (or similar ones of your own) to guide the
process.
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LESSON 6: Dew Drops
ANALYSIS & CONCLUSION
Use the questions from the activity sheet or your own
questions to discuss the experimental data. Ask students
to determine whether they should accept or reject their
hypotheses. Review the information in the Scientific
Inquiry section on pages 14–16 to discuss valid and
invalid hypotheses.
ASSESSMENT/GOALS
MODIFICATIONS/EXTENSIONS
Modifications and extensions provide alternate methods
for performing the lesson or similar lessons. They also
introduce ways to expand on the content topics presented
and think beyond those topics. Use the following
examples or have a discussion to generate other ideas
as a class.
Upon completion of this lesson, students should be able
to …
• Use two jars to compare the two setups at the same
time.
• Add ice-cold water, room-temperature water, and hot
water to different jars, and place them in the same
location (outside, in a dry room, in a bathroom, etc.).
What processes do you observe? Try another location
to see if the processes are different.
• Apply a scientific inquiry process and perform an
experiment.
• Compare and contrast solids, liquids, and gases and
give examples of each.
• Tell the students that they can all cause condensation
to take place. When they blow their hot breath on a
mirror, condensation is occurring. The water vapor in
their breath condenses when it hits a cooler mirror.
Try it out in class or have them test it out at home
with their parents’ permission.
• Define and identify different physical changes between
states of matter, specifically condensation and
vaporization.
• Understand the conditions required for condensation
to occur.
• Define and provide examples of elements and
compounds (see Differentiation in the Classroom).
• Define energy and its relation to physical changes
(see Differentiation in the Classroom).
K-4
See Lesson 7: The Moving Molecule Stomp for a
fun activity to illustrate the motion of particles in
solids, liquids, and gases and changes between
those states of matter.
REAL-WORLD APPLICATIONS
• A similar process occurs on the windows of
buildings. On a cold winter day, water droplets may
form on the inside of a window as warm air from
inside the building touches the cold window. In
contrast, on a hot summer day, water droplets may
form on the outside of a window of an airconditioned building as warm water vapor particles
in the outside air touch the cool window.
COMMUNICATION
Discuss the results as a class and review the activity sheet.
Review the information in the Scientific Inquiry section on
pages 14–16 to discuss the importance of communication
to scientific progress.
You Be The Chemist® Activity Guide | page 81
LESSON 6 ACTIVITY SHEET: Dew Drops
OBSERVE & RESEARCH
1. Write down the materials you see. ____________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
2. How might these materials be used? __________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
3. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an
image of the example.
Term
Definition
Example (write or add image)
Matter
Solid
Liquid
Gas
Physical change
Melting
Freezing
Vaporization
Condensation
You Be The Chemist® Activity Guide | page 82
LESSON 6 ACTIVITY SHEET: Dew Drops
4. Consider what will happen to jars filled with water of different temperatures and why.
uWrite your hypothesis. ______________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
PERFORM YOUR EXPERIMENT
Part One
1. Add hot tap water to a jar until it is half full.
2. Put the lid on the jar, and place it on a table. Watch what happens.
3. Pour the water out of the jar. Dry the inside and outside of the jar.
Part Two
1. Add cold tap water to a jar until it is half full. Then, add a few ice cubes to make the water very cold.
2. Put the lid on the jar, and place the jar on a table. Watch what happens.
ANALYZE & CONCLUDE
1. In Part One, do water droplets form on the inside or outside of the jar? ______________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
2. How did the water droplets get there? __________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
You Be The Chemist®Activity
ActivityGuides
Guide | page 83
LESSON 6 ACTIVITY SHEET: Dew Drops
3. In Part Two, do water droplets form on the inside or outside of the jar? ______________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
4. How did the water droplets get there? ________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
5. The physical change when a gas becomes a liquid is called ________________________________________________.
6. The physical change when a liquid becomes a gas is called ________________________________________________.
7. Have you ever seen the processes of condensation and vaporization take place at home? If so, when? If not, provide
another example of each change. ______________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
8. Is your hypothesis valid? Why or why not? If not, what would be your next steps? ____________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
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LESSON 6 ACTIVITY SHEET: Dew Drops
EXPAND YOUR KNOWLEDGE—ADVANCED
1. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an
image of the example.
Term
Definition
Example (write or add image)
Element
Compound
Energy
2. Compare and contrast the three states of H2O (water).
__________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
3. Describe how energy causes matter to change states. Give examples.
______________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
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LESSON 6 ACTIVITY SHEET: Dew Drops
ANSWER KEY Below are suggested answers. Other answers may also be acceptable.
OBSERVE & RESEARCH
Glass jars, water, ice …
1. Write down the materials you see. ____________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
Glass jars may be used to hold a substance. Water may be used to drink, bathe, or clean. Ice
2. How might these materials be used? __________________________________________________________________
may be used to reduce the temperature of a substance. These materials may be used together to show physical changes.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
3. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an
image of the example.
Term
Definition
Matter
Any substance that has mass and takes up space;
matter is generally found as a solid, liquid, or gas
on the earth.
Solid
A state of matter characterized by a definite volume
and a definite shape.
Liquid
A state of matter that has a definite volume but no
definite shape; a liquid will take the shape of the
container that holds it, filling the bottom first.
Gas
A state of matter that has no definite volume or
shape; a gas will take the shape of the container
that holds it, filling the entire container.
Physical change
A change that alters the form or appearance of a
substance but does not change its chemical
makeup or create a new substance.
Melting
A physical change in which a substance changes
states from a solid to a liquid.
Freezing
A physical change in which a substance changes
states from a liquid to a solid.
Vaporization
A physical change in which a substance changes
states from a liquid to a gas.
Condensation
A physical change in which a substance changes
states from a gas to a liquid.
Example (write or add image)
You Be The Chemist® Activity Guide | page 86
LESSON 6 ACTIVITY SHEET: Dew Drops
ANSWER KEY Below are suggested answers. Other answers may also be acceptable.
4. Consider what will happen to jars filled with water of different temperatures and why.
Water droplets will form on the inside and outside of a jar because of differences in
uWrite your hypothesis. ______________________________________________________________
temperature. As water vapor touches the cooler areas of the glass, it condenses and forms water droplets on that part of
______________________________________________________________________________________
the glass.
______________________________________________________________________________________
PERFORM YOUR EXPERIMENT
Part One
1. Add hot tap water to a jar until it is half full.
2. Put the lid on the jar, and place it on a table. Watch what happens.
3. Pour the water out of the jar. Dry the inside and outside of the jar.
Part Two
1. Add cold tap water to a jar until it is half full. Then, add a few ice cubes to make the water very cold.
2. Put the lid on the jar, and place the jar on a table. Watch what happens.
ANALYZE & CONCLUDE
Droplets of water form on the inside of the jar in the
1. In Part One, do water droplets form on the inside or outside of the jar? ______________________________________
first setup.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
The hot temperature of the water causes some of the water to vaporize. Then, the
2. How did the water droplets get there? __________________________________________________________________
vaporized water comes in contact with the sides of the jar. The sides of the jar are cooler and will cause the water vapor to form into droplets
______________________________________________________________________________________________________
along the inside of the jar.
______________________________________________________________________________________________________
You Be The Chemist® Activity Guide | page 87
LESSON 6 ACTIVITY SHEET: Dew Drops
ANSWER KEY Below are suggested answers. Other answers may also be acceptable.
Droplets of water form on the outside of the jar in
3. In Part Two, do water droplets form on the inside or outside of the jar? ______________________________________
the second setup.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
The water vapor in the air comes in contact with the outside of the jar. Because the water
4. How did the water droplets get there? ________________________________________________________________
inside the jar cools the glass, the water vapor in the air will condense on the outside of the jar when it touches the cool glass.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
condensation
5. The physical change when a gas becomes a liquid is called ________________________________________________.
vaporization
6. The physical change when a liquid becomes a gas is called ________________________________________________.
7. Have you ever seen the processes of condensation and vaporization take place at home? If so, when? If not, provide
Yes, when you take a hot shower, condensation will cause water droplets to form on the mirror in
another example of each change. ______________________________________________________________________
your bathroom. Also, when you boil a pot of water to cook spaghetti or boil water for tea, some of the water will vaporize out of the pot.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
8. Is your hypothesis valid? Why or why not? If not, what would be your next steps? ____________________________
Answer 1: Valid because the data support my hypothesis.
______________________________________________________________________________________________________
Answer 2: Invalid because the data do not support my hypothesis. I would reject my hypothesis and could form a new one, such as …
______________________________________________________________________________________________________
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LESSON 6 ACTIVITY SHEET: Dew Drops
ANSWER KEY Below are suggested answers. Other answers may also be acceptable.
EXPAND YOUR KNOWLEDGE—ADVANCED
Have students complete this section if you used the advanced differentiation information, or challenge them to find the answers to these
questions at home and discuss how these terms relate to the experiment in class the next day.
1. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an
image of the example.
Term
Definition
Example (write or add image)
Element
A pure substance that cannot be broken down into
simpler substances by ordinary chemical or physical
means; an element is made up of only one type of
atom.
Compound
A pure substance made up of two or more
elements joined in a defined ratio.
Energy
The ability to do work or produce heat.
2. Compare and contrast the three states of H2O (water).
The three states of H2O are ice, water, and water vapor. Ice is a cold
__________________________________________________
and hard solid. Water is a liquid and flows easily. Water vapor is a gas and can be found in the air.
______________________________________________________________________________________________________
______________________________________________________________________________________________________
3. Describe how energy causes matter to change states. Give examples.
When energy is applied to matter, such as applying
______________________________________
heat to ice, it will cause the ice to turn into water. The removal of energy, such as putting water in a freezer, will cause water to turn into a
______________________________________________________________________________________________________
solid—ice.
______________________________________________________________________________________________________
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