I. Water of the World
Objectives:
- To recognize that although there is a lot of water on earth, very little of that water is drinkable.
- To realize ground water is a very small percentage of the earth’s water.
- To understand that we take care of our water.
Materials:
1. Globe
2. 5 gallons of water
3. Tablespoons
4. Container (such as aquarium)
5. Droppers
6. Graph paper
7. Small containers (quart jars)
8. Copies of activity handout (Appendix A)
Part A - Exploring the Globe
1. Look at the globe with the students. See if they can find where they live on the globe. Have them point out lakes, rivers, and oceans. Explain that these are called surface waters.
2. Ask the students if they know which kinds of water bodies are salt water and which are fresh water? Have they ever tasted salt water? Was it good?
3. Ask the students if they think there is more water or land on the globe. Is there water beneath the surface of the ground that we cannot see on the globe?
Part B - Aquarium Demonstration
As you do this experiment, stress that the amounts represent relative quantities of different types of water, not actual amounts.
1. Put 5 gallons of water in an aquarium or other container. Tell students to imagine the container represents all the water in the world.
2. Have students remove 34 tablespoons of the water and put them in a cup. Tell them this amount represents all the water in the world that is not the ocean
3. Have the students remove 26 tablespoons of water and then another 8 tablespoons of water from the cup containing the 34 tablespoons of water. Put each into separate cups. The 26 tablespoons represent the world’ ice caps and glaciers. The 8 tablespoons represent the world’s fresh water. A fraction of a tablespoon (1/10) represents the world’s fresh water lakes and rivers. Of that, all rivers amount to less than a drop.
4. Be sure to recycle the water. Use it to water plants.
Part C - Work Sheet: All the Water in the World (Appendix A)
1. Ask students to complete the activity work sheet.
2. The answers to drinking water percentages: 0.419% total and 2.799% grand total.
3. Ask students if the numbers surprised them. Did they realize that such a small percentage of the water in the world is fresh?
Part D - Bar Graph
1. Distribute graph paper.
2. Ask students to create a bar graph that shows 97% ocean, 2% ice caps and glaciers, and 1% fresh water.
Follow-up Questions
1. Why isn’t all fresh water usable?
Some is not easy to get at; it may be frozen or trapped in unyielding soils or bedrock fractures. Some water is too polluted to use.
2. Why do we need to take care of the surface water/ground water?
Water is very important for humans, plants/crops, and animals. If we waste water or pollute it, we may find that there is less and less of it available for us to use.
II. The Water Cycle
Objectives
- Students will understand that water on earth moves in a continuous cycle.
- Students will be able to explain the stages of the water cycle.
Part A - Evaporation Activity
Materials
1. Small dishes or jar lids (2 per group)
2. Tablespoons (1 per group)
3. Water
4. Light source (sun or lamp/light) (1 per group)
5. Plastic wrap and or lids to cover dishes
Procedure
1. Divide the class into pairs.
2. Have each pair of students get two dishes.
3. Put one tablespoon of water in each dish.
4. Place one dish in the sunlight or under a light source.
5. Let students decide if they want to cover their dishes or leave them uncovered.
6. Place the other dish in the shade.
7. Have each pair of students observe and record what happens to the water.
Discussion Questions
1. Which dish evaporated faster?
2. Where did the water go?
3. How did the water evaporate?
Part B - Condensation Activities
Materials (for groups of 2-3 students)
1. A clean, clear 2 liter plastic bottle for every 3 students
2. A box of wood matches for every 3 students
3. A thermometer strip for every bottle (available at fish stores)
4. An eye dropper
5. A strip of tape
6. A notebook to record data
Procedure
Session 1: Temperature changes in a closed bottle
1. Tape the temperature strip into the bottle so that you can read it.
2. Screw the bottle cap on tightly.
3. Lay the bottle on its side so you can easily read the temperature strip.
4. Read and record the temperature of the air inside the bottle.
5. Use both hands to squeeze the bottle as hard as you can.
6. After about 1 minute read the strip.
7. Then stop squeezing the bottle and read the temperature strip after 1 minute.
8. Record what happened to the temperature when you squeezed the bottle and when you stopped squeezing the bottle.
Session 2:
Making a cloud-in a-bottle
1. Open the bottle and pour in a few drops of water. Screw the bottle cap on tightly. Swirl the water around the inside of the bottle so that most of the inside of the bottle is wet.
2. Squeeze the bottle and observe the temperature again. What happened?
3. Lay the bottle on its side, open the bottle and push down to flatten the bottle to about ½ its normal size.
4. Have someone light a match, blow it out, and put the match inside the bottle while it’s still smoldering. Quickly release the sides of the bottle and put the cap on tightly.
5. Squeeze the bottle as before very tightly for about 1 minute. Quickly let it pop open.
6. Record your observations. Hopefully you saw a cloud form.
Explanation
When you squeezed the bottle the air pressure in the bottle increased, which raised the temperature. The warmer air caused the water in the bottle to evaporate (it became water vapor) and you could see it. When you let the bottle pop out, the air pressure in the bottle was lowered and so was the temperature. This caused the water molecules to condense into a cloud.
Part C - Precipitation Activity
Materials
1. A heat source to boil water
2. A pot in which to boil water
3. A Pyrex or other container with a handle
4. Ice cubes
5. A pie pan or other container
Procedure
1. Have students gather around you to see what happens to the pot with ice in it and to the moisture that drips form the pot into the pie tin.
2. Place a pot of water on the heat source until it comes to a boil.
3. Fill the Pyrex pot with ice.
4. Once the water is boiling, hold the bowl of ice over the steam.
5. Place the pie tin so that the water, which drips from the bottom of the bowl, will collect in the tin.
6. Continue to hold the pot of ice over the boiling water until all the students have a clear view of what is happening on the surface of the pot with the ice.
Discussion Questions
1. What did you see happening on the bottom of the bowl?
2. What do you see happening in the pie tin?
3. How did the water get on the bowl?
4. Were the water drops on the side of the bowl the same size? Why?
5. Which drops looked like rain?
6. Which drops looked like a cloud?
7. How were the big drops formed?
Explanation
The small misty drops, which have condensed onto the side of the bowl of ice, represent a cloud. The winds in a cloud blow the small drops around so that they collide with others making bigger and bigger drops. When the drops become so large that the upward motion of the air cannot keep them in the sky, the drops fall as precipitation. If the temperature is cold enough, the drops will freeze as crystals, making snow. If the drops get together first and then freeze, the precipitation will be hail.
III. Water Usage
Objectives
- To identify ways in which water is used.
- To determine how much water families use each day
- To recognize the importance of conserving water
- To determine ways in which water can be conserved
Part A - Detective Work
Materials
- Copies of activity handouts (Appendix B,C, and D)
Procedure
1. Tell students that today they are going to be water detectives who have been called in to solve a case of mysterious occupants.
2. Distribute the copies of the case story and survey.
3. Be sure students write down their hypotheses before completing their surveys.
4. Explain how to fill out the survey. Explain how to make tally marks each time the activity takes place. Ask students to ask their family members to help complete the survey for one day-families can become more aware of how much water they use in the process.
5. After students have completed the survey, discuss the results.
Part B - Brainstorming About Water Conservation
1. 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 class followed that practice, how much water would it save in a year?
2. Are there ways to conserve water that would not be a good idea (e.g., not brushing teeth or washing)?
3. 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.
Adapted from: Water Cycle Teachers Page.
Water: A Never -Ending Story.
http://www-k12.atmos.washington.edu/k12/pilot/water cycle/teacherpage.html>
Note: For a map of the United States that shows the amount of water used in a day, visit
http://ga.water.usgs.gov/edu/mapuscototfresh.html
Note
: For a graph that shows the amount of freshwater withdrawals in the United States, state by state, visit http://water.usgs.gov/outreach/poster1middle_school/Page6.html
IV. Water Purification
Objective
To use the example of natural water purification to show students that healthy ecosystems provide services to people that are essential to life.
Part A - Our Local Watershed
Procedure
1. Have students visit EPA’s Surf your Watershed website and type in their zip code to find their watershed.
2. Have them click on the Index of Watershed Indicators and then the Impaired Water map to see the general condition of their watershed.
3. Have a list of zip codes for neighboring suburbs and rural areas for them to review and compare.
Discussion
1. What is the condition of streams in urban, suburban, agricultural or rural watersheds?
2. What kinds of pollution could you expect in these different kinds of areas?
3. Where would you expect the most nutrient pollution? The most pesticides and herbicides?
4. What watersheds probably have the most sedimentation, heavy metal pollution and thermal (heat) pollution?
5. Where might you expect to find the most pathogens in the water?
Part B - Are We Dry or Wet?
Procedure
Have students look at the USGS Water Watch site and judge whether or not their region is presently dry, wet, or average.
Discussion
1. What effect might a drought have on natural purification of waters? (Hint: Pollutants already in the water could be concentrated, but runoff from roads, lawns, and agricultural fields would likely be much lower).
2. What effect might a flood have? (Hint: It depends on whether or not there are healthy ecosystems surrounding the water body).
Adapted from: Science Netlinks.
Ecosystem Services - Water Purification.
http://www.sciencenetlinks.com/lessons_printable.cfm?DocID=275
V. Water Quality and Monitoring
Objectives
- To learn about and be able to recognize local aquatic life
- To understand why certain aquatic organisms no longer exist in our local waters
Materials
- Body of water
- Small fish nets
- Collection device
- Field Guide
- Classification Key
- Magnifying glasses
- Plastic bug boxes
Procedure
1. Reinforce the concept of an ecosystem in a visual way.
2. Discuss pollution of watersheds as it pertains to a lake, pond, or river
3. Fill up the collection trays with water from the pond. Remind students that aquatic animals must remain in water to breathe.
4. Using the net, scrape along the underside of plants, skim the surface of the water, or collect gumball-size mounds of mud from the bottom
5. By turning the net inside out, transfer any collected critters and debris into the collection trays. Repeat this collection and transfer several times
6. For field analysis, have students re-group in a designated “Research Station” area.
7. Have students identify and record the numbers of the macroinvertebrates they collected. Make sure all macroinvertebrates and debris are returned to the pond in a timely manner.
8. Have students rinse out the nets and collection containers well; collect gear together.
9. Compile the lists of types of animals found and look up the class to which each one belongs. (This can be done in the classroom or in the field.)
10. Have the students write up their results and discuss their differences.
Adapted from: HI Field Science Programs Teacher Resources
. BUGS! Clues to the Environment.
http://www.yni.org/hi/resources-teacher/post-trip/bugs.html
