In the first part of this lesson, students will simulate the amount of water on the earth and look at the part of that water that is fresh and available for human use. The second and third parts of the lesson will help students understand water and land reclamation.
Grade 7, Science — Earth and Space Science, Earth Systems
C. Describe interactions of matter and energy throughout the lithosphere, hydrosphere and atmosphere (e.g., water cycle, weather and pollution).
Y2003.CSC.S01.G06-08.BC.L07.I04 / Earth Systems
04. Analyze data on the availability of fresh water that is essential for life and for most industrial and agricultural processes. Describe how rivers, lakes and groundwater can be depleted or polluted becoming less hospitable to life and even becoming unavailable or unsuitable for life.
Grade 7, Science — Science and Technology, Understanding Technology
A. Give examples of how technological advances, influenced by scientific knowledge, affect the quality of life.
Y2003.CSC.S04.G06-08.BA.L07.I01 / Understanding Technology
01. Explain how needs, attitudes and values influence the direction of technological development in various cultures.
Y2003.CSC.S04.G06-08.BA.L07.I02 / Understanding Technology
02. Describe how decisions to develop and use technologies often put environmental and economic concerns in direct competition with each other.
- Faucet or jug with a pinhole large enough to drip water
- Measuring cup
- Globe or world map
- Three clear 2-liter bottles
- Liquid soap
Part 1: Water Demonstration
(adapted from Virginia Department of Education, Lessons From the Bay)
- Set up a demonstration area in the classroom with water containers, salt, an eyedropper and a globe or world map. Fill one container with one liter of water. Write “1 liter = 1000 ml” on the board. With each subsequent step, write the measurements on the board in the form of a mathematical statement, when appropriate. You may choose to ask students to assist in this demonstration.
- Before proceeding with the demonstration, place a bucket underneath a dripping faucet and note the time. Allow the faucet to leak throughout the lesson; the results will be used at the end of the class. (If a faucet is not available, you can suspend a gallon jug over the bucket. Prick the bottom of the jug with a pin or small nail to allow drops to escape.)
- Tell students that the one liter of water represents all the water on the earth. Have a student pour 30 ml of the water into a second container. Ask students what they think the remaining 970 ml represents. Pour a tablespoon of salt into the 970 ml of water to help students see that this water represents the oceans. Remind them that ocean water is unfit for human consumption and that the 30 ml of water poured out represents all of the fresh water in the world.
- From the container holding the 30 ml of water, have another student pour 6 ml into a third container. The 24 ml left represents all of the earth’s fresh water that is “locked up” or frozen at the earth’s poles and therefore unusable.
- The third container with 6 ml of water represents the water that is not in the oceans and not part of the ice caps. Ask students if they believe the water represented by the 6 ml is usable. Ask what might make the water unusable. (Some of it is polluted; some is trapped underground and unreachable.) Ask students to estimate how much of that 6 ml is actually usable.
- With the eyedropper, put one drop of water into a fourth container. Explain that the drop represents all the usable water available on earth — 8.4 million liters per person.
- Next, turn off the dripping faucet (or remove the jug), and record the length of time that the faucet or jug dripped.
- Measure how much water dripped in the amount of time you designated, and show the students how easily water can be wasted.
Part 2: Restoring the Cuyahoga River
Cuyahoga River pictures are available at www.generationscvnp.org/photos.aspx.
- Ask the students what they know about the Cuyahoga River. Expect to get answers about its name and about it catching on fire. Distribute the CVNP handout Cuyahoga River Recovers and the Considering the Cuyahoga student handout.
- Have the class read Cuyahoga River Recovers. Ask a few students to fill the bottles about half full of water. Talk about the role oil and other pollutants played in the famous 1969 Cuyahoga River fire.
- Instruct the students to write down on the Considering the Cuyahoga handout what they think would happen if you added one cup of oil to one bottle of the water. (The oil and water will separate.) Pour the oil in the water and shake it up. Liquids that don’t mix are called immiscible.
- Repeat the process using one cup of liquid soap. Ask the students to write what they think will happen. (Soap will mix with water, but bubbles will form.) The water is clear, but is it clean? Liquids that mix with each other are called miscible.
- With the third bottle, prepare to add one-half cup of oil and then one-half cup of liquid soap. Ask the students to write what they think will happen. The oil will mix with the soap and then with the water. This shows that oil might be present and we wouldn’t know. The water is clear, but is it clean?
- A 9½-minute video is available at http://wheredoesitgo.org/it.htm that shows what happens to waste water from homes and from the environment.
- Ask the students to make a list of ways they can protect and conserve water. They could read the CVNP Watershed Stewardship handout and/or visit the following sites:
Part 3: Restoring the Land
Krecji Dump pictures are available at www.generationscvnp.org/photos.aspx.
- Share the following background information with the class:
The National Park Service Organic Act, 1916
“…The service thus established shall promote and regulate the use of the federal areas known as national parks, monuments, and reservations hereinafter specified by such means and measures as conform to the fundamental purpose of the said parks, monuments and reservations, which purpose is to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations.”
Ever since the Apollo space missions so graphically showed us how finite the planet Earth is, people have altered the way they think about our home planet. No more can we take what we want from the land and then, when finished, just leave the debris and scars behind.
- Explain to the students that they’re going to do a simulation to illustrate the concept of “preserve and protect.”
- Distribute the Restoring the Land student handout. Have the students read the introductory paragraphs.
- Talk about the Krecji Dump site. Show primary source pictures to the class or have students look at them individually on a computer.
- Discuss what happens to the land when it is used by people and not left alone. Discuss the concept of climax forest as the mature stage of natural forest for its environment. In Ohio, this would be the growth of oak, maple, beech and other large trees.
- Have the students work with a partner and number the five stages of succession to the climax forest. The order is 3, 1, 2, 5, 4.
- After a few minutes, go over the correct answers. Discuss why this is the order of growth. Compare this natural process to the work Cuyahoga Valley National Park has done to restore the Krecji Dump site. Here, the land was so polluted that most of the soil had to be removed. Eventually, the property will be reshaped and replanted with native vegetation.
- Ask the students to make a list of ways they can protect land from pollution.
- As a class, compile a list of ways that students can be more green for both land and water use.
- Use the Restoring the Land student handout as an activity to foster discussion. Students can use the checklist in the handout to evaluate their work on this topic.