You will need:

• Jar
• Plants
• Bottle cap or shell of water
• Soil
• Sand
• Small rocks
• Procedure

Layer the bottom of the jar with the small rocks. Next add a layer of sand, then a layer of soil. Put the bottle cap on top of the soil as well as the plants. Put the lid on. Put the jar in a sunny place and see how the water cycle works.

Background

Many communities obtain their drinking water from underground sources called aquifers. Water suppliers or utility officials drill wells through soil and rock into aquifers for the ground water contained therein to supply the public with drinking water. Homeowners who cannot obtain their drinking water from a public water supply, will have their own private wells drilled on their property to tap this supply.

Unfortunately, the groundwater can become contaminated by harmful chemicals, including improper disposal of household chemicals such as lawn care products and cleaners and any number of other pollutants. These chemicals can percolate down through the soil and rock and into the aquifer, and eventually the well. Such contamination can pose a significant threat to human health. The measures that must be taken by well owners and operators to either protect or clean up contaminated aquifers is quite costly.

Objective

To illustrate how water is stored in an aquifer, how groundwater can become contaminated, and how this contamination ends up in the drinking water well. Ultimately, students should get a clear understanding that what happens above the ground can potentially end up in the drinking water below the ground.

Materials needed

• 1 6" x 8" clear plastic container that is a least 6"-8" deep (shoe box or small aquarium)
• 1 lb. of modeling clay or floral clay
• 2 lbs. of white play sand
• 2 lbs. of aquarium gravel (natural color if possible) or small pebbles. (As any small rocks may have a powdery residue on them, you may wish to rinse them and dry on a clean towel prior to use. It is best if they do not add cloudiness to water.
• 1 drinking water straw
• 1 plastic spray bottle (be sure the stem that extends into the bottle is clear)
• 1 small piece (3 x 5) of green felt
• 1/4 cup of powered cocoa
• Red food coloring
• 1 bucket of clean water and small cup to dip water from bucket
• Scotch tape

Procedure

1. To one side of the container place the small drinking water straw, allowing approximately 1/8 of an inch clearance with the bottom of the container. Fasten the straw directly against to the long side of the container with a piece of tape. Explain to the students that this will represent two separate well functions later in presentation (if not placed at this time, sand will clog the opening).
2. Pour a layer of white sand completely covering the bottom of the clear plastic container, making it approximately 1" deep. Pour water into the sand, wetting it completely, but there should be no standing water on top of sand. Let students see how the water is absorbed in the sand, but remains around the sand particles as it is stored in the ground and ultimately in the aquifer.
3. Flatten the modeling clay (like a pancake) and cover the sand with the clay (try to press the clay into the three sides of the container in the area covered). The clay represents a "confining layer" that keeps water from passes through it. Pour a small amount of water onto the clay. Let the students see how the water remains on top of the clay, only flowing into the sand below in areas not covered by the clay.
4. Use the aquarium rocks to form the next layer of earth. Place the rocks over the sand and clay, covering the entire container. To one side of your container, slope the rocks, forming a high hill and a valley. Now pour water into your aquifer until the water in the valley is even with your hill. Let students see the water around the rocks that is stored within the aquifer. They will also notice a "surface" supply of water (a small lake) has formed. This will give them a view of both the ground and surface water supplies which can be used for drinking water purposes.
5. Next, place the small piece of green felt on top of the hill. If possible, use a little clay to securely fasten it to the sides of the container it reaches.
6. Using the cocoa, sprinkle some on top of the hill, while explaining to students that the cocoa represents improper use of lawn chemicals or fertilizers, etc.
7. Use the food coloring and put a few drops into the straw, explaining to students that often old wells are used to dispose of farm chemicals, trash and used motor oils. They will see that it will color the sand in the bottom of the container. This is one way pollution can spread through out the aquifer over time.
8. Fill the spray bottle with water. Now make it rain on top of the hill and over the cocoa. Quickly students will see the cocoa (fertilizer/pesticide) seep down through the felt and also wash into the surface water supply.
9. Take another look at the well you contaminated. The pollution has probably spread further. Now remove the top of the spray bottle and insert the stem into the straw, depress the trigger to pull up the water from the well. (Water will be colored and "polluted.") Explain that this is the same water a drinking water well will draw up for them to drink.

Background

Water in lakes, rivers and swamps often contains impurities that make it look and smell bad. The water may also contain bacteria and other microbiological organisms that can cause disease. Consequently, water from surface sources must be "cleaned" before it can be consumed by people. Water treatment plants typically clean water by taking it through the following processes: (1) aeration; (2) coagulation; (3) sedimentation; (4) filtration; and (5) disinfection. Demonstration projects for the first four processes are included below:

Objective

To demonstrate the procedures that municipal water plants use to purify water for drinking.

Materials needed

• 5 Liters of "swamp water" (or add 2 cups of dirt or mud to 5 liters of water)
• 1 Two-liter plastic soft drink bottle with its cap (or cork that fits tightly into the neck
• 2 Two-liter plastic soft drink bottles - one bottle with the top removed and one bottle with the bottom removed.
• 1 1.5-Liter (or larger) beaker or another soft drink bottle bottom
• 20 grams of alum (potassium aluminum sulfate - approximately 2 tablespoons; available in pharmacy or spice isle in grocery store)
• Fine sand (about 800 ml in volume)
• Coarse sand (about 800 ml in volume)
• Small pebbles (about 400 ml in volume) (Hint: washed natural color aquarium rocks will work)
• 1 large (500 ml or larger) beaker or jar
• 1 coffee filter
• 1 rubber band
• 1 tablespoon
• A clock with a second hand or a stopwatch

Procedure

1. Pour about 1.5 L of "Swamp Water" into a 2 L Bottle. Have students describe the appearance and smell of the water.
2. Aeration is the addition of air to water. It allows gases trapped in the water to escape and adds oxygen to the water. Place the cap on the bottle and shake the water vigorously for 30 seconds. Continue the aeration process by pouring the water into either one of the cut off bottles, then pouring the water back and forth between the cut off bottles 10 times. Ask students to describe any changes they observe. Pour the aerated water into a bottle with its top cut off.
3. Coagulation is the process by which dirt and other suspended solid particles are chemically "stuck together" into floc so that they can be removed from water. With the tablespoon, add 20 g of alum crystals to the swamp water. Slowly stir the mixture for 5 minutes.
4. Sedimentation is the process that occurs when gravity pulls the particles of floc (clumps of alum and sediment) to the bottom of the cylinder. Allow the water to stand undisturbed in the cylinder. Ask students to observe the water at 5 minute intervals for a total of 20 minutes and write their observations with respect to changes in the water's appearance.
5. Construct a filter from the bottle with its bottom cut off as follows:
   1. Attach the coffee filter to the outside neck of the bottle with a rubber band. Turn the bottle upside down and pour a layer of pebbles into the bottle - the filter will prevent the pebbles from falling out of the neck.
   2. Pour the coarse sand on top of the pebbles.
   3. Pour the fine sand on top of the coarse sand.
   4. Clean the filter by slowly and carefully pouring through 5 L (or more) of clean tap water. Try not to disturb the top layer of sand as you pour the water.
6. Filtration through a sand and pebble filter removes most of the impurities remaining in water after coagulation and sedimentation have taken place. After a large amount of sediment have settled on the bottom of the bottle of swamp water, carefully - without disturbing the sediment - pour the top two-thirds of the swamp water through the filter. Collect the filtered water in the beaker. Pour the remaining (one-third bottle) of swamp water back into the collection container. Compare the treated and untreated water. Ask students whether treatment has changed the appearance and smell of the water. Advise students that the final step at the treatment plant is to add disinfectants to the water to purify it and kill any organisms that may be harmful. Because the disinfectants are caustic and must be handled carefully, it is not presented in this experiment. The water that was just filtered is therefore unfit to drink and can cause adverse effects. It is not safe to drink!

Background

Every day, the average American uses about 50 gallons of water for drinking, bathing, cooking and maintenance. Most people, however, are unaware of the source of their water.

In the United States, about 88 percent of the population is supplied by community water supply systems. The other 12 percent is supplied by non-community means, such as campgrounds, resorts and private wells. Sixty-four percent of public water systems use surface water as their source, the other 36 percent use ground water from wells.

The aesthetic properties of the drinking water from these public systems is often affected by the source of the water. Ground water often has a slightly metallic taste, and may contain high amounts of minerals. Surface waters, on the other hand, usually have a musty taste and look cloudy.

Treatment techniques aim to produce a water that is: safe for human consumption; appealing and good tasting to the consumer; and conforms with applicable State and Federal regulations at the lowest possible cost.

Objective

This taste test will illustrate the differences between ground water and surface water, highlight some of the common contaminants in natural water, and encourage student thought on the sources of drinking water.

Materials needed

• 1 gallon of distilled water
• 1 gallon of tap water (identify the source)
• 1 gallon of mineral water (or private well water, if available)
• 1 gallon of filtered tap water
• Cups for the class

Procedure

1. Mark a set of 4 cups for each student. Label each cup 1 through 4 and fill them with the different types of water. Make sure that similarly labeled cups contain the same type of water.
2. Indicate on the board the different types of water present in the four cups. Have the students work together in groups to try to identify different tastes, smells, and appearances in the water. Have each group write down their observations on each water sample, and identify which cup has which type of water.
3. After everyone has completed their observations, have the students mark their guesses on the board. Ask the students what types of impurities they would expect to find in the different types of water, and if their senses confirmed their intuitions. Record these observations on the board.
4. Reveal to the students which samples contained which type of water. Discuss with the students their observations and what other impurities might be found in these waters. Also discuss the source of water for the community. If anyone in the class lives in a location supplied by a private well, ask him/her to describe the water at their home, and how it compares to other water he/she drinks in the community.

Follow-up questions

• What are some possible sources of water in your community?
• Which type of water tasted best? Why?
• Which type of water would you consider safer to drink, ground water from a spring, or surface water from a stream?

This activity is designed to demonstrate to students what an average storm drain collects during a rainfall event and how the water from storm drains can impact the water quality and aquatic environments of local streams, rivers and bays.

Materials needed

Preparation

1. Introduce this activity with a discussion of storm drains and storm drain systems and their purposes. Discuss where the water and objects that float down into a storm drain go. Have students list all of the things that they can think of that might enter a storm drain during a rain storm.
2. Assign a group of students to each pollutant. Discuss each pollutant, including its use or origin and how it could enter the storm drain.
3. ave each group of students place their pollutant into the storm drain. Use the watering can to create rain to wash the pollutant into the waterway. While washing each pollutant into the waterway, review the pollutant and its use or origin. Discuss the following questions: How does the pollutant damage the environment? Do the people who are responsible for the pollutant want to damage the environment? Why did they do what they did? How can this type of pollution be stopped?
4. After adding all of the pollutants, examine the contents of the waterway. Discuss how the waterway has changed and how viewing this change makes the students feel.

Follow-up questions

• Why types of the pollution are natural?
• What types of pollution are added by people living in the local communities?
• How can we remove the pollution from the water?
• What could be done to stop pollutants from entering storm drains?

Variations

Have the groups of students responsible for the pollution think of ways to remove the pollution from the aquarium. Try some of the removal methods. Which pollutants were easy to remove? Which were difficult to remove?

Background

The land we live on is divided into watersheds. A watershed is a land area whose runoff drains into any river, stream, lake, or ocean. Small watersheds, such as the watershed for the creek, or the watershed for a pond, drain into small bodies of water, and cover small land areas. The runoff from small watersheds join together, and their combined areas become a new, larger watershed. Large watersheds, such as the Mississippi Basin and the Chesapeake Bay watershed, drain into large bodies of water, and cover immense land areas.

Despite their differences in sizes, all watersheds share common properties. They all perform the same function of transporting water over the Earth's surface. The watersheds encompass suburban lawns, parking lots and city streets. Water seeps down through the soil to aquifers, which are underground rivers that slowly move water below watersheds to outlet points at springs, rivers, lakes, and oceans.

Many human activities have an effect on watersheds. Construction projects like dams can limit the flow of water; construction of roads and buildings can divert and even increase the flow of water. Agricultural fertilizers can run off of crop fields and inadvertently fertilize harmful microorganisms in rivers and lakes, having an adverse effect on water quality and marine life. The irresponsible disposal of household and industrial chemicals can be harmful because these chemicals travel through the watershed, poisoning life and damaging natural ecosystems.

Watersheds can also have an effect on humans. Many communities use rivers and streams as their source of drinking water. Water treatment prepares this water for human consumption, but if the water is laden with chemicals and microorganisms, it can be difficult to treat effectively.

Floods are one of the major events in a watershed. Homes built on flood plains, low lying areas adjacent to rivers, are susceptible to flooding conditions when heavy precipitation exceeds the watershed's capacity to absorb water. Rivers, streams, and lakes overflow, threaten human lives, and damage or destroy roads, building, and flood control measures.

Watersheds can also become dry, causing water shortages for those who depend on their lakes and rivers for drinking water. It is clear that humans have a close relationship with watersheds. The responsible planning of watershed use and development is important to ensure the ecosystems sustained by the watersheds are not destroyed and to protect the health and safety of our communities.

Note: Prior to the demonstration, the teacher should engage the students in activities involving identification of a local watershed. Maps can be used to facilitate this activity, and a field trip to a local river or pond can serve to demonstrate the concept of a watershed. Ask students to identify where the water is coming from. How far does the watershed extend? For a small stream, the answer may be several hundred feet; but for a lake or river, the watershed may be much larger.

Objective

This experiment illustrates the basic properties of a watershed: how water flows from higher elevations to lover elevations, and how watersheds are interconnected. The students will understand how the placement of buildings, roads, and parking lots can be important to watershed runoff, and how careless use and disposal of harmful contaminants can have a serious effect on downstream watershed denizens.

Materials

• 1 large Tupperware container (about 1.5'W x 3'L x 1'H)
• 2 lbs. of modeling clay
• 3 lbs. of sand (any type)
• 2 lbs. of aquarium gravel
• 1 roll of wax paper (or tin foil, plastic wrap, etc. --water repellent surface)
• 1/4 cup of cocoa mix, iced tea mix, or other flavored drink mix (to represent chemicals)
• 1 spray bottle or bucket full of water

Procedure

(Note: Prepare steps 1 to 4 before students are present.)

1. Wash the aquarium gravel carefully to remove any powder residue that may add cloudiness to the water. Fill the container to about 2 inches from the bottom with the gravel. Slope the gravel slightly so that at one end (downslope), the gravel is only about 1⁄2 inch deep and at the other end (upslope), the gravel is about 3 inches deep. This gravel layer will represent the aquifer.
2. Mix the clay and the sand. The consistency of this mix should be gritty, with slightly more clay than sand. This mixture should allow water to run freely over it, but if left standing, the water should slowly permeate the surface. Add this mixture to the container carefully, so as not to disturb the slope of the aquifer already placed. The slopes should be similar, with about 2 inches of sand/clay mix overlying the gravel already placed, and on the downhill end there should be about 3" of gravel left exposed.
3. Carve a channel in the middle of the clay/sand layer, about 1⁄2 inch deep and about 1 inch wide. This channel will represent the main river of the watershed. Near the top of the slope, split the channel into two or three separate channels to represent tributaries. You may wish to add other tributaries along the main branch of the "river" to further illustrate other watersheds.
4. With some extra clay/sand mix, build little hills between the tributaries. These hills separate the smaller watersheds, but when looked at as a whole the entire "river" system is one watershed. You may also wish to add some small model trees or green felt to represent forests or fields. Buildings can be represented with small blocks of wood.
5. Along the main river, flatten out an area that is about 8 inches by 3 inches. Cut out a piece of wax paper to be about 4 inches by 3 inches in size. Stick this down onto the clay/sand mix, sloping it slightly towards the river. If necessary, use some clay to hold the edges down. Explain to students that this wax paper represents the impervious surface of a parking lot.
6. Fill the bottom of the aquarium up to about 2 inches from the bottom with water. The water should fill all of the aquarium gravel "aquifer" area, and should just reach up to the lowest extent of the clay/sand mixture. Explain to students that the aquifer captures and transports water that seeps down through the soil.
7. Using the spray bottle, simulate rain over the flattened soil area and the parking lot. Ask the students to note that the "rain" soaks through the soil, but runs off the parking lot to the river. Ask them what the effect would be if the entire watershed was "paved."
8. Sprinkle some cocoa mix over the sides of one of the smaller watersheds. Tell the students that the cocoa represents pollution. Over one of the unpolluted "watersheds," cause some rain with the spray bottle (*it may be necessary to cause more rain by pouring water). Note that the runoff from the rain is clean. Now, make it rain over the polluted area. Ask the students to note how the pollution travels down through the watershed, contaminating all downstream areas. Discuss with the students why the pollution is a problem, and what can be done to fix the problem.

Follow-up questions

• What are some possible sources of watershed pollution in your community?
• What other impervious surfaces besides parking lots can cause excessive runoff in a watershed?
• What can be done to reduce our impact on watersheds and their environment?