Prior to class:
Collect three clear, CLEAN plastic water bottles. Prepare
each of the bottles in the following manner:
Bottle 1 Fill with tap water and a few drops of yellow
food coloring. The water should be obviously yellow.
Bottle 2 Fill with tap water and add two teaspoons of
salt to bottle. Dissolve the salt fully.
Bottle 3 Fill with tap water and add enough clay, soil,
or sediment to make it cloudy.
1. On the board write the following question: “How
do you know that the water you drink is safe to consume?” Students
should respond to this question in their notebooks.
2. Once students have finished responding to the warm-up
question direct their attention to the front of the
classroom where you have the three bottles of water
and 3 glasses.
Pour a little water from each bottle into a glass.
Ask students which glass they would prefer to drink
Ask for a volunteer to drink from the clear water.
Students should not know that it includes salt. Then
should sip the yellow water. Once the teacher has
demonstrated that the yellow water is all right
to drink a student
volunteer may also sip it. NO ONE should drink the
cloudy water. Ask students what factors were their
3. Once students have mentioned clarity and color
of water, ask them if that was enough to distinguish
water was the most palatable. The answer is obviously
not. Open the discussion to establish what other
factors must be included. Make sure that the lack
of any obvious
smell, look, or taste does not mean the water is
good. Can the students give an example of a water
that would not be tasted, smelled or seen by the
use of their five senses alone?
4. Ask students who is responsible for making sure
that the water out of the tap is drinkable. (There
correct answers to this question. Some students
may receive their drinking water directly from
from a water utility company.) Students probably
do not know who takes care of their water. If
the previous big idea cycle this will merely
be a review.
5. Explain to students that by providing water
through pipes to a certain number of houses,
a water utility
company is responsible for following the standards
laid out by the Safe Drinking Water Act. The
Safe Drinking Water Act was established to
water in the U.S. This law focuses on all waters,
below or above ground, actually or potentially
drinking use. The Act authorized the Environmental
Protection Agency to establish safe standards
of purity and required
all owners or operators of public water systems
to comply with these health-related standards.
6. On an overhead share with students the “Water
arsenic still too high as deadline approaches” article.
If you can find an appropriate article for your part
of the country you might want to exchange it. Cover up
all but the title. Ask students what they know about
arsenic. Explain that this article is about arsenic in
drinking water and their purpose in reading this article
is to identify what questions they need to answer before
they can understand the article, specifically the scientific
7. Reveal the first paragraph, “Just one month
before…” allow students to read it by themselves,
or start students reading out loud to their classmates.
What questions does this first paragraph prompt? Ex.
What is arsenic? Why should we care if there is too much
in the water? What are federal standards? Why do we have
federal standards for arsenic? Why does Arizona have
too much arsenic in the water? Students should write
their questions down. You should collect these questions
on the overhead also.
8. Continue with each paragraph. Some paragraphs
will prompt a few questions. At the end
of the article make
sure that all the questions are displayed
9. Once the class has finished, have
the students work in groups to identify
have been addressed
within the article and which ones remain
and which ones need more information
can be answered.
10. Ask students if it is important
to know whether there is arsenic
Do they know
is arsenic in their water? Explain
that in the next lessons they will
water and should at the end of those
lessons be able to answer all the
of this lesson is to assess students’ prior knowledge
and to shape the set of learning experiences that follow
to best suit students’ needs.
1. Students’ prior knowledge about water quality standards
can be assessed by their responses to the ‘warm up’ question, “How
do you know that the water you drink is safe to consume?” and
the questions that they develop in response to the first
few paragraphs of the article.
2. Students’ prior knowledge about arsenic might also
be assessed in the questions they develop.