Jheri Leah Hurst

ESC 400

Hydrosphere I- Groundwater

 

Benchmark:

Explain how water exists below the Earth’s surface and how it is replenished (SCI.V.2.MS.3).

 

Benchmark Clarification: 

Precipitation can filter through the layers of the Earth and create groundwater, one type of useable water resource.

 

Lesson Objectives:

  1. Students will be able to explain what forms groundwater and describe groundwater zones.
  2. Observe and/or use several simple aquifer models.
  3. Locate areas of major aquifers on a U.S. map and name states.
  4. Determine how much water families use each day.
  5. Determine ways in which water can be conserved.

 

 

Anticipatory Set:

I will start by presenting the class with a glass of cold drinking water.  I will then ask the students if they know where the water came from. Hopefully the students will have a mixture of answers.  Some will say that it is really old, while others will say just a few minutes.

 

Key Concepts/Vocabulary:

Aquifer- an underground layer of rock or unconsolidated sands and gravels that is saturated with usable amounts of water/ above or between layers of impermeable rock or clay.

Artesian aquifer- an aquifer that is sandwiched between two layers of impermeable materials and is under great pressure, forcing the water to rise without pumping. Springs often surface from artesian aquifers.

Confined aquifer- see artesian aquifer.

Groundwater- water that infiltrates into the earth and is stored in usable amounts below the earth’s surface; within the zone of saturation.

Impermeable- not permitting water or other fluid to pass through.

Unconfined aquifer- an aquifer containing unpressurized groundwater, having an impermeable layer below but not above it.

Water table- the top surface of the groundwater.

Zone of Saturation-In a groundwater system this is the lower zone where all of its pore spaces contain water.

Zone of Aeration- In a groundwater system this is the upper zone where the pore spaces are filled with air.

Porosity- Percentage of a material’s volume that is pore space.

Permeability- Characteristic that measures how easily water flows through a rock.

Materials:

Overhead projector

Wipe-off transparency pens

U.S. map

Clear plastic cups (1 per student)

Drinking straws (1 per student)

Chipped ice

Lemonade or juice drink

Clear glass bowl

Aquarium gravel

Modeling clay

Water

Jar or bottle

Blue food coloring

Pump (from liquid soap bottle)

 

Teaching Strategies and Methods:

 

Advance Preparation-

  1. Fill a jar or bottle with water. (Size will depend on how large the glass bowl is.) Tint the water blue with food coloring (probably one drop). Set it aside.
  2. Pat out a “pancake” of modeling clay. Size it to fit into the glass bowl with a good (but not necessarily tight) fit.
  3. Make a transparency of each of the teacher sheets.

 

Procedures-

 

Setting the Stage

  1. Pass out clear plastic cups and drinking straws to each student.
  2. Put the word “aquifer” on the board and ask students if anyone knows what the word means. Then put the Latin derivation on the board so they can see the parts of the word and how we arrived at its definition.
  3. Tell students they are all going to make a model aquifer. Fill each cup with chips of ice. The ice represents rock and soil-like materials underground. Pour into each of their cups lemonade or juice drink. The drink represents groundwater. Explain that the cup and drink represent an aquifer and groundwater. The bottom of the cup is the layer of rock or soil that keeps the water from seeping down any further. The top of the water is the water table, the top of the underground water layer.
  4. Have students sip some of the liquid. Explain that they have just simulated a well by using their straw to “pump” the liquid from the aquifer. They have lowered the water table.
  5. Ask what they would have to do to bring the water table back up to its original level. Compare adding more liquid to rainfall, which replenishes or “recharges” groundwater.

 

Activity

 

A. Show the students the transparency of the aquifer diagram teacher sheet.

1. As you point out the aquifers, the water tables, and the wells, relate these to the drink cup model. (NOTE: Do not go into differentiating between confined and unconfined aquifers at this time. You will do this later.)

2. Let several students color the diagram with wipe-off transparency pens. Have them use blue for water (including groundwater) and other colors for the ground’s layers. This will make it more clear for the students.

 

B. Construct a more complicated aquifer model for the students to observe.

1. Use one glass bowl (instead of cups each student used before). As you layer materials in the bowl, talk to the students about what each one represents. (NOTE: Leave the aquifer overhead up.)

2. The bottom of the bowl is an impermeable layer (water cannot pass through it), just as impermeable layers of rock or clay underlie other layers underground.

3. Put in a layer of sand. It represents an aquifer (it can hold water). Pour enough of the blue tinted water into the sand to saturate it. What kind of water is this?

            (Groundwater)

4. Put in a layer of modeling clay overlying the sand aquifer. Clay is impermeable,

 so the aquifer is trapped between two impermeable layers. Ask the students what kind of aquifer this is. (Confined) Point out the confined aquifer on the overhead.

5. Pour a layer of aquarium gravel on top of the clay. This represents an aquifer. Pour in some blue tinted water. Tell the students to note the top of the water. What is this called? (Water table) What kind of aquifer is this? (Unconfined, because there is no impermeable layer on top of it) Point out the unconfined aquifer on the diagram.

6. Tell the students that this is quite like the ground under their feet may be. Aquifers are present in many locations, although in some places they are deeper in the ground than in other places.

7. Put the pump from a liquid soap or other container in the model’s unconsolidated aquifer. Ask the students what they think will happen if you work the pump. Let one of them try it while you hold it so the end of the tube stays above the modeling clay layer. Dispense some blue-tinted water into a cup.

8. Tell the students that this is much the way a well works. Remind them of the

demonstration they completed using the drink cups. Point out the well on the overhead.

 

C. Have the students examine a map showing groundwater resources in the United States.

  1. Share the following information with the students: Groundwater is almost everywhere. The layers of rock and soil-like material under the ground hold water in varying amounts. Some places have a lot of groundwater, but it is deep in the earth and not easy to get from wells. Some places do not have as much groundwater. Some places have abundant supplies of groundwater. In these places people rely on water from wells for irrigating crops and for water supplies for both individual families and whole communities.
  2. Show the students the transparency of the teacher sheet “Major U.S. Aquifers.” Explain that the crosshatching on this map marks the places in the continental U.S. where abundant fresh water is available from aquifers. In these areas, large groundwater supplies are used by industries, communities (municipal water systems), and irrigation of crops. In the areas where there are no markings there is less likely to be plentiful groundwater available. These places will, however, have wells that supply individual households and livestock operations.
  3. Ask a student volunteer to come up and mark on the map (with a wipe-off transparency pen) about where your community is located. Is it in an abundant aquifer region?
  4. Ask the students to answer the following questions by naming states. (Allow them to refer to a labeled map if it is needed.)

a. Name several states where plentiful groundwater is available almost

everywhere. (Florida, Mississippi, Louisiana, Iowa, Delaware, Nebraska, Michigan, New Jersey)

b. Name several states that have the least groundwater in many places.

(Montana, Wyoming, Colorado, Utah, Pennsylvania, Kentucky, West Virginia, New York, Vermont, New Hampshire, Maine)

 

Content:

Ø      Aquifer is an underground layer of rock or soil that holds the water that we call groundwater. The word “aquifer” is derived from the Latin “aqua,” meaning “water,” and “fer,” meaning “to yield.”

Ø      The ability of a geological formation to yield water depends on two factors—porosity and permeability. Porosity is determined by how much water the soil or rock can hold in the spaces between its particles (as with a sponge). Permeability means how interconnected the spaces are so that water can flow freely between them.

Ø      There are two types of aquifers:

o        One is a confined aquifer, in which a water supply is sandwiched between two impermeable layers (geological formations through which water cannot pass). These are sometimes called artesian aquifers because when a well is drilled into this layer, the pressure is so great that water may spurt to the surface without being pumped. This is an artesian well.

o       The other type of aquifer is the unconfined aquifer, which has an impermeable layer (or one of lower permeability) under but not above it. It is the most common type.

Ø      Aquifers may be categorized according to the kind of material of which they are made:

o        A consolidated aquifer is composed of a rock formation (that is porous or fractured).

o       An unconsolidated aquifer is composed of a buried layer of sandy, gravelly, or soil-like material.

Ø      The top surface of the groundwater is called the water table. The water table depth varies from area to area and fluctuates (rises and falls) due to seasonal changes and varying amounts of precipitation. Excessive pumping from the aquifer can also lower the water table.

Ø      Groundwater Resources in the United States

o       Major U.S Aquifers

o       Perhaps the largest aquifer in the world is the Ogallala aquifer located in the Midwestern part of the United States. This aquifer is named after a Sioux Indian tribe. It is estimated to be more than two million years old and to hold about 650 trillion gallons (2,500 trillion liters)! It underlies parts of 8 states, stretching about 800 miles (1,288 km) from South Dakota to Texas. The Ogallala aquifer supplies vast amounts of water to irrigate the crops grown in this vitally important agricultural area.

 

Website:

http://ga.water.usgs.gov/edu/qausage.html

 

Students will access this site to further their knowledge of how the United States uses groundwater. Once at the site, pairs of students will have to read the information on the website to answers questions on the worksheet. (Worksheet attached)

 

 

Real World Context:

Ask students to ask their families to help complete the home water use survey for one day—families can become more aware of how much water they use in the process. A weekday, when families have more of a routine, will provide the best picture of daily water use. (It might be interesting, for extra credit, to compare weekday and weekend water use.) After students have completed the survey, discuss the results. Have students look at their water use surveys. Ask them to consider what their families could do to reduce the amount of water they use. How much water would that conserve? If everyone in the class followed that practice, how much water would it save in a year? Are there ways to conserve water that would not be a good idea (e.g., not brushing teeth or washing)? Give each student a copy of the “Water Conservation Tips” activity handout. Look it over as a group to see how it compares with your list. Suggest that students take it home and post it in the bathroom or kitchen.

 

 

Assessment:

After completion of the home water use survey, have students write a brief newsletter for their family reporting on the results of the survey. (Don’t mention names, except to honor those who used the least amount of water per person.) Students should include water conservation suggestions.

 

Evaluate students on their newsletter to their families using the following three-point rubric:

ü      Three points- newsletter includes the main results of their survey and included at least three different ways that their family could conserve water.

ü      Two points- newsletter includes few results from survey and less than three conservation suggestions to family.

ü      One point- newsletter includes one result of the survey and contained no suggestion on how their family could conserve water in their household.

 

Bibliography:

 

Earth Science- Science Explorer Textbook: Prentice Hall 2002

 

Michigan Science Benchmark Clarification, Instruction, and Assessment

www.miclimbscience.org

 

USGS: Water Science for Schools- Water Use Question and Answers

http://ga.water.usgs.gov/edu/qausage.html

 

St. Johns River Water Management District: Palatka, Florida- Home Water Use Survey

http://sjr.state.fl.us/programs/outreach/pubs/order/pdfs/as_survey.pdf

 

United States Environmental Protection Agency

http://www.epa.gov/students/

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

 

 

 

 

 

 

 

 

 

Water Use Internet Worksheet

As you and your partner navigate through the site, http://www.epa.gov/students/,

complete the following questions as best as you can.

 

  1. What is most of the freshwater in the U.S. used for? What percent is used for irrigation? Domestic (self supplied)?

 

 

 

 

 

  1. Which states use the most water?

Go to this link, http://ga.water.usgs.gov/edu/maptotal.html  and find out how much water the state of Michigan uses on a daily basis.

 

 

 

 

 

  1. Why is groundwater so important to us?

 

 

 

 

 

 

 

 

  1. For what purpose did our state use the most water?

 

 

 

 

 

 

 

  1. In the year 2000, how many gallons of water per day did Idaho use in its “trout farms”?