Title: Understanding Watersheds
Essential Question: What is a watershed?
Objective: Learners will be able to describe a watershed as an area of land where rainfall drains toward a
common body of water. Learners will identify hierarchical levels of watersheds within a particular geographic
area.
NGSS Standards Addressed:
Develop a model to describe the cycling of water through Earth's systems driven by energy
MS-ESS2-4.
from the sun and the force of gravity.
MS-ESS2-2.
Construct an explanation based on evidence for how geoscience processes have changed
Earth's surface at varying time and spatial scales.
Materials: (for Engage demonstration) 3 or more bowls that graduate in size so that one will “nest “ inside
another, sufficient amount of water to fill the smaller bowls to overflowing, block of wood or other item to
serve as a stand for the bowls to rest on inside one another.
(for Explore activity group of 3 to 4) shallow pan (such as a dishpan, or baking pan), 4 to 5 sheets of
newspaper, spray bottle filled with water, blue food coloring, white plastic sheet (cut from a kitchen garbage
bag) towels for cleanup
Phase One: Engage the Learner
These activities mentally engage learners with an event or question. Engagement activities stimulate interest and help to
make connections with what learners know and can do. The teacher provides an orientation to the topic and assesses
learners’ prior understanding of the concepts addressed in the lessons.
Learners are likely to know that rainwater originates from water vapor condensing in clouds in the atmosphere. They may
also know that rainfall interacts differently with different soil surfaces and other materials that it contacts on the ground.
What the teacher can do:
What the learners are doing:
1. Begin a discussion with these questions, “What happens to the rain
1. Sharing ideas and observations about
water when it falls?” “Where does the water in a stream come from?”
their prior experiences and knowledge
Give learners a chance to offer a variety of descriptions and ideas
of rainwater.
about what happens to stormwater when it falls.
2. Offering suggested definitions for the
2. Ask the learners to suggest a definition for the word “watershed”.
term watershed.
Point out the fact that it is a compound word made of water and shed. 3. Observing the behavior of water
Accept all suggestions without making judgments of correctness.
overfilling the capacity of a container
3. Set up a demonstration of bowls arranged one inside the other,
and flowing into a larger container.
supported by a short stand under each bowl, so that there is space
4. Suggesting possibilities for how the
between the bottom of each bowl and the bottom of the bowl it is
system they’ve just observed could be
sitting inside. Pour water into the smallest bowl until it overflows into
a model for a natural system involving
the next larger bowl. Continue pouring water until the next larger
rainwater.
bowl fills and overflows into the next larger bowl. The demonstration
ends when water flows into the largest of the bowls in the group,
which is sitting underneath all the others.
4. Draw attention to the fact that the water overflowed from the smaller
containers into the larger ones. Ask the learners to suggest instances
in the natural world where water can be thought of as contained
within a structure of some sort, (lake, pond, stream, etc.). How could
rainwater interact with the natural world in some ways that are like
the bowls they have just observed?
Phase Two: Explore the Concept
Students encounter hands-on experiences in which they explore the concept further. They receive little
explanation and few terms at this point, because they are to define the problem or phenomenon in their own
words. The purpose at this stage of the model is for students to acquire a common set of experiences from
which they can help one another make sense of the concept. Students must spend significant time during this
stage of the model talking about their experiences, both to articulate their own understanding and to
understand another's viewpoint.
What the teacher can do:
What the learners are doing:
1.
1. Crumpling sheets of newspaper and
placing them at random into a shallow pan.
2.
3.
4.
5.
6.
Provide each group of learners with 5 sheets of newspaper and a
wide shallow container such as a dishpan or baking pan. Instruct the
learners to crumple the sheets one by one and place them into the
pan.
Provide each group with a sheet of white plastic that is slightly larger
than the area of the pan. This can be easily obtained by cutting a
trash bag. Instruct the learners to place the sheet over the clumps of
paper and tuck the edges into the sides of the pan. Challenge the
learners to imagine that they are looking down upon a landform
with hills and valleys.
Provide each group with a spray bottle containing water, which has
been colored blue with food coloring. Instruct each group to choose
a member who will spray the water onto the plastic in order to
simulate rain falling on the landform.
Ask learners to describe how the water behaves as it lands on the
plastic sheet. Suggest that they notice the trickles of water that
move from higher places to lower places. Suggest that they notice
the pools of water that collect in pockets and folds of the plastic.
Challenge the learners to use their imaginations to picture the scene
in the pan as if it were an aerial view of an area of land made up of
hills and valleys. Prompt them to notice that water falling on a ridge
of land will flow down either side of the ridge into an area that is
bounded by higher elevations.
Prompt the learners to notice that pools of water have collected in
places where water drained from a particular area that is bounded
by ridges and higher surfaces.
2. Covering the lumps of paper with a white
plastic sheet and observing the uneven
surface of the plastic. Imagining the surface
of the plastic as a representation of a
landform with hills and valleys.
3. Spraying blue colored water onto the
plastic sheet and visualizing the result as
rainfall onto a landform.
4. Describing the behavior of the “rainfall”
on the uneven surface of the “landform”.
5. Observing the behavior of water as it falls
on a high point that divides sections of land
into separate areas.
6. Observing the behavior of water as it
collects in low areas after it drains from
higher areas.
Phase Three: Explain the concept and define terms
Only after learners have explored the concept will the curriculum and/or teacher provide the scientific explanation and
terms for what they are studying. The teacher may present the concepts via lecture, demonstration, reading, or
multimedia (video, computer-based). Learners then use the terms to describe what they have experienced, and they
begin to examine mentally how this explanation fits with what they already know.
What the teacher can do
What the learners are doing:
1. Present the PowerPoint presentation titled “What is 1. Listening to the presentation.
a Watershed?”
2. Use notes from the presentation to guide the
2. Taking note of new terminology
explanation of terms such as: divide, water body,
runoff, infiltration, erosion, river basin, sub3. Asking questions for clarification and answering
watershed
questions that check for comprehension of information.
4. Noting details of maps showing watersheds.
Phase Four: Elaborate/Extend the Concept
Students elaborate on their understanding of the concept. They are given opportunities to apply the concept in unique
situations, or they are given related ideas to explore and explain using the information and experiences they have
accumulated so far. Interaction between the students is essential during the elaboration stage. By discussing their
ideas with others, students can construct a deeper understanding of the concepts.
What the teacher can do:
What the students are doing:
1. Prompt the learners to recall the nesting bowls
1. Constructing an analogy that explains the connections
demonstration that was shown at the beginning of the between smaller watersheds and larger watersheds.
lesson. Challenge them to draw a connection between
the water flowing from smaller bowls to larger ones
and the hierarchy of watersheds from smaller to
larger.
2. Proposing ideas to explain the movement of pollutants
2. Present a hypothetical situation to the learners in
through watersheds from smaller streams into larger
which a pollutant enters the watershed scale and
ones.
challenge them to hypothesize about possible paths
through which the pollutant could move into a larger
watershed.
3. Present information about the hypoxic zone in the
Gulf of Mexico and ask to learners to propose
reasonable explanations for the buildup of nutrients
that have stimulate the overgrowth of algae in the
ocean waters.