IT'S CLEAN, IT'S FRESH AND ONLY THREE BILLION YEARS OLD -
Grades 7 - 9
This lesson is about the water cycle. Without the ability of
water to vaporize, condense and fall back to Earth, life on this planet
would not survive. This lesson explores, using some very entertaining
and fun, hands-on activities, the process behind each phase of the water
cycle; evaporation, condensation, precipitation and collection. The Water
Cycle Lesson will take two approximately 45-minutes class
Bill Nye the Science Guy - "The Water
Students will be able to:
- identify the four major parts of the Water Cycle;
- describe the processes which cause water evaporation, condensation
- describe the variables that would affect the rate of evaporation;
- describe the difference between rain, snow, sleet and hail;
- give three examples of collection in their own environment;
- describe why the re-use of water is so important to living things
Per student group or pair of students:
- clean ice cubes
- small cup of fresh water
- stoppered vial of damp air
- copies of labeled diagram of water cycle apparatus
- a dry bottle
- 1-2 hole stopper
- 2 short, flanged pieces of glass tubing
- 2 pieces of flexible tubing
- 1 dropper
- 1 - 1-meter long piece of glass tubing
- 1 ring type stand
- 2 clamps
- 1 meter stick
- 1 small bottle of food coloring
- 1 small amount of Vaseline
- 2-3=liter plastic soda bottle with cup
- fish tank flexible thermometer
- two safety matches
- hydrologic cycle
- surface area
- molecular motion
- condensation nuclei
- vapor pressure
Give each team of two students a small cup of water, a clean
ice cube and a covered vial of damp air. Ask them to list as many
about each substance they can see in three minutes.
Allow students to sip the water and lick the ice cube in order to make
observations. Elicit responses from the students regarding the
and differences between the samples.
To give students a specific focus for viewing, tell them to carefully
and listen to the first short segment of the program and list one
property of water that they may have omitted in their observations a few
minutes before; one that is very clearly mentioned in the first segment
(that the water in their cup is approximately 3.5 billion years
Explain that condensation is the process where water vapor turns back
liquid water. This section of the video provides an excellent explanation
of the process and will provide a nice lead-in to the next activity. To
focus the students' attention, tell them to be prepared to answer this
about his segment:" How is condensation different from
START tape just after musical introduction to program.
after the words "you could be drinking what was once dinosaur
Take a large swallow of water and restate the last phrase ("You
be drinking what was once dinosaur spit.") To check for
ask for other examples of the origin of the water in their cups. Prepare
for a lively discussion!
To continue their focus, tell students to watch the next segment of the
video and write down the term Bill Nye gives for the "Moving around
RESUME from "water is just an amazing substance."
at the point where the terms "water cycle" and "hydrologic
cycle" appear on screen in large white letters, immediately after
Ask students to list three other examples of cyclic patterns in their own
environment. Briefly discuss a few of the examples taking care not to
the impact of the fast pace of the video. Tell them to watch the next
of the video and to continue their focus, have them list four major parts
of the water cycle.
RESUME PLAY. STOP after the phrase, "...it floats to
the sea to start the cycle all over again!" To check for
ask the students for specific examples of evaporation, condensation,
and collection. If possible, use examples from their own environment.
Hand out a labeled diagram of the water cycle apparatus shown in the
Explain that in this section of the lesson, students will explore the
that affect evaporation, condensation and precipitation.
Hand out Evaporation Investigations and materials listed on their
sheet (use one kit per student team). Have students complete the
with as little help from you as possible. It might be useful to point out
the materials at their disposal. Allow students to design one procedure,
carry out the procedure, collect data and report on their findings in
At the end of the investigation the students should complete the
at the end of the investigation.
Upon conclusion of the investigation, discuss the results with the
(Variables, such as temperature of the air, water circulation, surface
etc. will affect the evaporation rate.)
In order to understand the concept of evaporation, it is important to be
able to visualize the process on the molecular level. After a discussion
of the factors affecting the rate of evaporation, encourage students to
carefully watch and listen to the next segment pertaining to molecular
To give students a focus for viewing, ask them to pay particular
to the demonstration using plastic beads as molecules.
FAST FORWARD to black and white screen entitled "Molecular
PLAY and STOP at the conclusion of this segment. To check
for comprehension, probe students for the molecular basis for evaporation
of water based on the illustration of the "bead" molecules (Not
all molecules are moving at the same speed).
START TAPE at "Who's the Scientist." PAUSE
after "See that! That uh..." To check for comprehension, ask
to provide the term in question (condensation).
RESUME PLAY. PAUSE after "...is where clouds come from."
Check for comprehension by asking how a cloud might form in the
RESUME PLAY. PAUSE after "...water needs a place to stick for
condensation to happen." Check for comprehension by asking students
to explain how condensation is different from evaporation with respect to
energy losses and gains.
In this investigation students will attempt to forma cloud by causing
to occur in a clear plastic 2-3 liter soda bottle (NOTE - This won't work
until a key ingredient is added. This missing substance will be revealed
int he next segment of the video.)
Hand out materials for "Cloud in A Bottle Investigation".
students to make a circle by bending the flexible thermometer and taping
it together. Then have them put the thermometer in the bottle, recap it
and record the temperature in the bottle. How, have them squeeze the
and describe what happens. The temperature should rise if they squeeze
enough.) Next, unscrew the cap and add enough water to cover the bottom
of the bottle, recap the bottle and squeeze again. While they are
the bottle and heating it up, ask what would happen if they suddenly
pressure on the bottle (they should realize that the air in the bottle
cool). Cooling the air as the video clearly shows produces condensation
and should form a cloud. Direct students to perform that task now!
You will see some disappointment on their faces when absolutely nothing
Explain that in this next section of the video, Bill Nye attempts to
the same experiment in much bigger bottle - with much the same results as
the students will experience. To give students a specific focus for
tell them they should discover why their attempt at cloud-making didn't
RESUME PLAY at "It's just the water vapor in the nearby air
condensed." PAUSE after "...three, two one..." To
check for comprehension, ask students to relate this to their own attempt
to make a cloud.
RESUME PLAY from above. PAUSE after "We'll need the
from these two matches!" At this point allow the students to add
to their bottles. Mention that dust is just a simple term used to
all kinds of particles to which water molecules can cling. The technical
term for this "dust" is condensation nuclei.
RESUME PLAY. STOP after cloud formation and
science!" To check for comprehension, ask the students to write a
for a cloud. They should be able to list ingredients, materials,
etc. just like in a cookbook.
Preview the process of evaporation and condensation. Explain, however,
unless the condensed water falls back to Earth, there would be no cycle
and now water for life forms to use. In this next segment we will explore
the process of precipitation.
Direct students to listen for an explanation of how water in the clouds
can return to Earth.
START after "way cool science". PAUSE after
is rain! Isn't it great?!" To check for comprehension PAUSE
and ask students to restate the process that produces precipitation.
molecules need to cling to one another to become large enough to
RESUME and PAUSE after terms , RAIN, SLEET, HAIL AND SNOW
appear on the screen. Check for understanding of terms by asking class to
name the four common forms of precipitation. This is a good point to
the differences between sleet and hail, commonly confused forms of
(Sleet forms as rain freezes on the way down through cold air. Hail forms
from a cyclic motion which produces multiple stages of freezing and
This produces the concentric ring patterns often seen in a cross section
of a large hailstone.)
RESUME PLAY and STOP after "...all the time it's
It's just another "-shun" word." To check for
ask the students for the meaning of collection as it pertains to the
By way of introduction, tell students that in this final section of the
program, the importance of reusing the limited water available on Earth
To give student a specific focus for viewing, tell them to carefully
the next segment of the video to get a clear demonstration using a
to represent the Earth and a dropper to represent the amount of usable
START after "old film clip" and PAUSE after the
words "We must put an qual amount of water into our bodies each day
or we'd perish...and that includes you, pal!"
To check for comprehension, asks students to recall the amount of water
that is available to drink. You could also begin a discussion of water
and its effect on the limited fresh water available for humans at this
or bring this concept in as an extended topic after the lesson on the
In the next section of the Bill Nye program, the importance of the water
cycle is, shall we say, STRESSED! HAVE THE STUDENTS WATCH THE SEGMENT
CAREFUL ATTENTION FOR SEVERAL REASONS WHY THE WATER CYCLE IS SO
RESUME PLAY. STOP after "We'll be back in a moment
Bill Nye the Science Guy." To check for comprehension, have the
write a brief essay on the importance of the water cycle to life forms on
earth. Discuss some of their interpretations as a class. Ask for things
that people can do to protect the water cycle.
START after "Just Do It" logo. Conclude the lesson with
the "Water Cycle Rap."
This demonstration will reinforce the concepts shown in the video
"Molecular Motion." It is often difficult for students to
molecules (matter) not only contain mass but take up space as well. In
demonstration you will show that evaporation occurs when droplets of
are placed in a dry, sealed bottle. See Materials List for Evaporation
and diagram attached.
Vapor pressure is that part of air pressure that is caused by water vapor
in the air As water evaporates, the number of molecules of water for a
volume of space increases. This in turn creates a greater pressure. With
a tube containing food coloring it is possible to approximate the
of water through the changes in the height of the fluid indicator. Set up
the apparatus as shown int he diagram. Make sure the indicator fluid is
at a measurable point on the meter stick. With a dropper partially filed
with water, carefully, without squeezing any water down into the bottle,
place the dropper in the hole in the stopper of the bottle so that there
is a seal.
Discuss the fact that since there is now water to evaporate in the bottom
of the bottle the air pressure in the bottle is constant. (A change in
would change the pressure inside the bottle.)
Gently squeeze a few drops into the bottle and ask the class to describe
what happens. As they watch the indicator fluid rise in the long glass
ask the students if the rate of change of the fluid in the tube is
(The indicator rises quickly at first and then slows down. It will reach
a certain level depending on the temperature of the room. This level is
called the saturation vapor pressure which means that the air in the
can't evaporate any additional moisture without condensing an equivalent
amount.) In this investigation, the added molecules of evaporating water
take up space int he bottle, which in turn caused pressure inside. The
way to release the pressure is by pushing the indicator fluid forward, up
the tube. The instrument that has just been observed is called a
In the previous section we focused on the process of evaporation. In this
section we will reverse the process and explore how water vapor
If this part of the lesson is to be completed on another day, a review of
the previous lesson on evaporation would be recommended.
Use the "manometer" to see how temperature affects the amount
of evaporation by using bottles with differing air temperatures. Graph
rise in the indicator fluid for each of three different temperatures.
students display and explain their results.
Make a poster-sized diagram of the water cycle labeling each of the four
Set up the "Cloud in a Bottle" and start with polluted water
of clean water. Try different forms of polluted water like salty, soapy,
muddy, etc. and see what happens. Describe results.
- Measure the amount of evaporation which takes place on a square
of lawn on a sunny day.
- Write a report on one type of water pollution commonly found in
area. Telecommunications using e-mail with students across the state and
nation comparing information.
- Acid rain (one type of water pollution) can be measured easily
pH paper or a pH meter. Compare the acidity of the rain in your area with
other students' via the Internet.
Have your Earth Science teacher help you find the Dew Point and Relative
Humidity of the air. Keep a record of the changes that take place for one
month. Compare this to any weather changes that occur.
Write a fictional short stry on the life history of a water
Master Teacher: Gib Brown
Mountain Lake Public Broadcasting/Plattsburgh, NY
NOTE TO TEACHER
This lesson will focus on the relationship between the different phases
of water and the importance of each phase in the completion of the water
cycle. "Bill Nye, the Science Guy: The Water Cycle" allows you
to interject several hand-on activities that will allow students to
the relationships between the different phases of water and the
of the recycling of water on life forms on earth.
Lesson Plan Database
Thirteen Ed Online