TW_water_activity

							Fellow name: Tina Wey

Title of Lesson: Water, Water Everywhere, But How Many Drops to Drink?

School: University Senior High School

Grade Level: 9-10 (can be modified for other grades)

Subject(s): Integrated Coordinated Science (ICS), Science Research and Exploration (SRE)


Summary
Students learn how and why water is important in our lives and what some current issues are.
Topics covered include: the chemistry of water, global and local water sources and usage, water
conservation issues, and water filtration. Students investigate adhesion and cohesion in a penny
drop activity. They estimate their own water usage and discuss how this fits into current water
usage issues. Finally, they test and evaluate purification methods in a water filtration activity.

In what way is your lesson/activity inquiry-based?
Students are asked to think about and discuss water as it pertains to their everyday life and their
world. Each of the activities challenges the students to explore a scientific or engineering topic
and draw their own conclusions before discussing the results as a class.

Time Required
Two 90-minute classes

Group Size
4-6 students per small group

Cost to implement
< $50 for everyday items

Learning Objectives
After this lesson, students should be able to:
Describe the molecular structure and polarity of water
Define adhesion, cohesion, surface tension, and capillary action, and explain these phenomena in
    terms of water‟s chemical properties
List the major components of the world‟s water, and know that most of the world‟s water is
    saltwater in the ocean and that < 1% is freshwater available for human use
Relate global patterns of water shortage to patterns of climate, precipitation, and population
Define a watershed, and list inputs and outputs of a watershed
Identify the watershed of which they are a part
Discuss general water-related issues in the context of „too little, too much, or too dirty‟
Define physical, chemical, and biological water filtration
Describe the general purpose and methods of water filtration
Introduction / Motivation

Day 1 – What is water, and why is it important to us?
As a review, ask students if they know the chemical formula for water, and if they can draw a
water molecule in their notebooks. Have one student volunteer to draw it on the board. Which
poles are positive and negative, and why? Discuss how the structure and polarity of water leads
to some important chemical properties. For example, if you dip one end of a piece of paper into a
beaker of water, what happens? Why? Define adhesion, cohesion, surface tension, capillary
action, and give examples of each. Do the „Drops on Penny‟ activity, and have the students try to
explain their results in terms of the chemical properties of water. (~30 min)

So where is the world‟s water found? Have them look at a map and how much of the world‟s
surface is covered by water. Where is most of the world‟s water? (In the oceans.) What are the
major sources of water? List these one by one on the board. Have students guess what percentage
of water is contained in each source. Write the actual percentages on the board. An easy visual
demo to use along with this is to use a gallon of water as an analogy and pour out appropriate
amounts for each source. Are most of these water sources easily accessible for our use? (No, e.g.,
saltwater, icecaps.) The point is that a very tiny percentage of water is easily accessible for
human consumption and use (<1% readily accessible freshwater). How is water distributed
globally? Give a short PowerPoint presentation using maps to illustrate global patterns of
climate, population, water usage, and water shortage. (This should be tied into what they learned
in the ICS Earth science unit.) Both water availability and usage determine if there is a water
shortage. Americans use, on average, the most water of any country in the world. What are the
major uses of water in the US? Have students guess what the largest use of water in the US is
(agriculture) and try to list other major uses of water. Give them the actual list, and present
surprising or interesting water facts. (~30 min)

What is Los Angeles‟ water situation? (We have low rainfall and high demand.) Where does our
water come from? Many of the students may not realize that we import much of our water from
distant sources. Show maps of our major water sources, and show how dependent we are on
water from distant sources and snowmelt. (Quick use of Los Angeles water trivia here to test the
students‟ knowledge is a good way to get them guessing and involved in the topic.) Introduce
watersheds, and talk briefly about the Ballona Watershed. Show a map of the watershed, and
point out the school. Remind them that substances that get put into the water will get into the
watershed and be transported elsewhere. End the first day with the „Personal Water Usage‟
worksheet. How many gallons of water do the students think they use each day? Each week?
Have the students fill out their predictions at the end of class and finish the rest of the worksheet
as homework. (~30 min)

Day 2
Start by discussing the students‟ water usage worksheets. Were they surprised by how much
water they used? What activities used the most water? Discuss this in terms of Los Angeles‟
water usage status, and discuss some simple, everyday water conservation techniques the
students can employ. Have students turn in their homework. (~15 min)
Water shortages are very prominent in Los Angeles, but what are some other types of water-
related issues we face? These issues can generally be categorized into „too little, too much, or too
dirty‟. Today we will focus on the „too dirty‟ aspect. Water contaminants can come from both
natural and man-made sources, and much of the world‟s population does not have access to safe
drinking water. How do we determine if water is clean or dirty? What can we do to purify water?
Have the students brainstorm some ways to purify water. Hopefully the students come up with
some real-life examples (e.g., Brita, sand). Present a brief overview of filtration techniques
(physical, chemical, biological) and describe how each works. (~15 min)

Present the „Water Filtration Challenge‟ and have students do the activity. (~45 min)

Procedure

 „Drops on a Penny‟
Students do this activity in groups of 4-6. How many drops of water will fit on the surface of a
penny before the water spills over? Have the students guess beforehand, and then see how many
they can actually fit. What happens if you use drops of alcohol instead of water? Describe what
happens in each case. Why is there a difference between what happens with water and alcohol?
Have the students explain this based on what they know about the chemical properties of water.
** An extension of this activity that we used in the SRE class was to have students observe drops
of water and alcohol on different substances (e.g., foil, wax paper) and have them guess what an
unknown clear liquid is based on how it behaves.

Water Filtration Challenge
Show the students the dirty water sample. (The dirtier, the better, without being hard to deal
with. I have used various combinations of potting soil (for darkness and particulate), flour (for
cloudiness), tea tree oil (for smell), vegetable oil (for oil sheen), and other everyday substances.
The students are grossed out by the visual dirt and smell. One trade-off is that it is hard to detect
any added oil if the water is very dark.) Their challenge today is to design a filtration system
using only everyday items to get the dirty water as clean as possible. We will judge at the end
which group wins. They can use the materials in any combination, but can only use what they
have. Present each material and how it filters (cheesecloth, coffee filter, sand, charcoal). Show
the students how they can set up their funnel in the ring stand, with a clean beaker below to catch
the filtered water. Give the students a set amount of time to design and use their filter (~30
minutes depending on time in period) for the activity. Have the students design their apparatus
first (drawing this worked well) before allowing them to build the apparatus and start filtering.
Students should be allowed to re-filter samples (hence the second clean beaker), but let them
figure this out themselves. At the end of the period, have the groups present their clean sample,
and discuss as a class which filtration technique was most successful. How do we define a clean
sample? (E.g., clarity, color, lack of smell, etc.) How do we judge which filtration technique is
most successful? (E.g., purity, time taken, amount recovered, etc.) You can also have the class or
instructors choose a cleanest sample and give that group a prize. The students should come away
with an appreciation of the challenges in designing effective filtration techniques, while
considering real-world limitations.
** As an extension if you have time, the filtration activity can be used in combination with water
quality testing kits. Students will need to learn how to use the kits ahead of time, but they can use
the kits to test the water samples before and after filtration to chemically assess the effectiveness
of filtration methods.

Materials List
Each group will need:

Day 1
Penny
Water dropper

Day 2
Filtration kit:
1 ring stand
1 funnel
2 pieces cheesecloth
2 coffee filters
200 ml sand
200 ml charcoal
2 clean beakers
Tape (to keep cheesecloth and coffee filters in place)
(Optional) Water testing kits and tubes
(Optional) Gloves
Pre-made dirty water samples (enough for ~250 ml per group)

Safety Issues
Students should be careful with glassware. If something breaks, they should not touch the
broken glass, but inform the instructors to clean it up. Students should not taste the „dirty‟ water.

Lesson Closure
Wrap up the lesson with a review of the concepts the students have covered and have them apply
them to real-life challenges faced when dealing with water and the environment.
** In the SRE class, an excellent extension of this lesson was to discuss current events,
specifically the Gulf Oil Spill, which was (still is as of this writing) going on at the time. We
discussed biological and ecological impacts of the oil spill, and we modified the filtration
activity to focus on filtering oil out of water.

Is this lesson based upon or modified from existing materials? If yes, please specify
source(s) and explain how related:
The water demonstration borrows from the EPA lesson “The World‟s Water” by Frank H.
Forrester and the USU Stream Side Science activity “Where‟s The Water?” and many water facts
come from Water.org. The watershed presentation borrows from Terri Hogue‟s summer
presentations. Global maps are taken from the UNEP GRID-Arendal project and EarthTrends
Environmental Information, and Los Angeles topological maps are taken from the USGS. The
map presentation borrows ideas from the EPA activity “A Global View Of The Wet Earth”. The
water usage homework assignment is modified from the EPA lesson “Water You Doing About
This?” The water filtering activity is based on the WaterPartners International activity “Mock
Muck Mini-Unit”.

References

Websites
http://earthtrends.wri.org
http://maps.grida.no
http://static.water.org/pdfs/WPHighCurric13_0.pdf
http://water.org/learn-about-the-water-crisis/
http://water.usgs.gov/
http://www.ballonacreek.org/
http://www.epa.gov/OGWDW/kids/wsb/index.html
http://www.theriverproject.org/tujunga/teaching612.html

Lessons/Activities
EPA The Water Sourcebooks. Grade Level 9-12: Drinking and Wastewater Treatment.
   http://www.epa.gov/OGWDW/kids/wsb/pdfs/9122.pdf
EPA The Water Sourcebooks. Grade Level 9-12: Introduction to Water.
   http://www.epa.gov/OGWDW/kids/wsb/pdfs/9121.pdf
LaMotte Company. 2003. Outdoor monitoring series: Water quality monitoring. Chestertown,
   MD. www.lamotte.com
Tujunga Watershed Project. Educational Curricula: Make a watershed difference-Youth guide to
   the Tujunga/Pacoima Watershed for grades 6-12. Action steps: Step #1-Map your watershed.
   http://www.theriverproject.org/tujunga/curriculum/MAWD.Step1.pdf
Water.org Lesson Plans. 13.0 (High school) “Mock Muck” Mini-Unit.
   http://static.water.org/pdfs/WPHighCurric13_0.pdf

Presentations
Burke, Megan. 2009. The urban water cycle. Emerson Middle School.
Hogue, Terri. 2009. Watersheds. UCLA SEE-LA GK-12 Summer Institute (Los Angeles, CA).
Utah State University Extension. Stream side science. USU Water Quality Extension.
   http://extension.usu.edu/waterquality/htm/educationalprograms/streamsidescience


Attachments
Water presentation
Filtration worksheet
Personal water usage worksheet (student homework)


List CA Science Standards addressed:
Grades 9-12, Earth Sciences, California Geology:
9c: Students know the importance of water to society, the origins of California‟s fresh water, and
the relationship between supply and need.
Lesson Implementation Comments

The water trivia in the presentation was a big hit. The personal water usage homework worked
pretty well in terms of getting students to think about their own personal usage, and it facilitated
a really nice discussion the second day. The water filtration challenge was a great way to get the
students actively involved and thinking about how to solve a problem, and they had a lot of fun
with it.

The format of the lesson is flexible, and different topics (e.g., earth science, biology) can be
emphasized more or less depending on the unit in which this lesson is implemented. I
implemented it during the chemistry unit, so the emphasis is on chemistry, with tie-ins to earth
sciences, biology, and ecology. I found it is very important to summarize the activity and walk
through the steps with class before allowing them to start, even when they are given a lot of
flexibility (as with the water filtration activity). Be sure to emphasize important steps (e.g., for
the water filtration, make sure to emphasize that they need to measure the starting amount in
order to determine the percent recovered). In the SRE class, we actually split the lesson up over
multiple weeks, and it seemed to work pretty well.