- Grade Level:
- Upper Elementary: Third Grade through Fifth Grade
- State Standards:
- Utah Science Standards
Strand 5.2: Properties and Changes of Matter:
Essential Question: What physical and chemical changes in matter can be observed in nature?
Utah Science with Engineering Education Standards:
Strand 5.2: PROPERTIES AND CHANGES OF MATTER All substances are composed of matter. Matter is made of particles that are too small to be seen but still exist and can be detected by other means. Substances have specific properties by which they can be identified. When two or more different substances are combined a new substance with different properties may be formed. Whether a change results in a new substance or not, the total amount of matter is always conserved.
Standard 5.2.1 Develop and use a model to describe that matter is made of particles on a scale that is too small to be seen. Emphasize making observations of changes supported by a particle model of matter.
Standard 5.2.3 Plan and carry out investigations to determine the effect of combining two or more substances. Emphasize whether a new substance is or is not created by the formation of a new substance with different properties.
Matter is the “stuff” of the universe. Everything that has mass and volume, no matter how small, is made of matter. Air, water, rocks, trees, stars, and animals all consist of matter. Matter can exist as a solid, liquid, or gas (or plasma) and can change in many ways. Physical changes are those in which the shape, size, or state of the matter changes, but the substance is still essentially the same. For example, chopping up a carrot or ice melting into water are both physical changes. Chemical changes are those where one or more substances are combined to produce a new substance. At the end of a chemical change, you have a new substance. Burning a piece of paper would be a chemical change, as would baking a cake.
Ozone is an invisible gas made of 3 oxygen atoms. High levels of ozone in the lower atmosphere can cause human health problems and can contribute to the greenhouse effect. Car exhaust, the result of a chemical change in fuel, is a major contributor of ozone to the lower atmosphere. Canyonlands National Park also monitors ozone at ground level. Scientists monitor ozone levels to provide real time data on air quality to the public.
Unlike in the lower atmosphere, Ozone plays a positive role in the upper atmosphere. The stratospheric ozone layer blocks much of the sun’s UV light from reaching the earth’s surface. Normal quantities of UV light are good for such things as plant growth and suntans. But, increased UV light from a damaged ozone layer leads to increased incidences of skin and eye disease in humans as well as damage to some wildlife and plants.
The single largest factor in the destruction of the ozone layer is a family of chemicals called chlorofluorocarbons (CFCs). This reaction is a chemical change in the ozone molecule. Humans used CFCs to manufacture hundreds of different products, including Styrofoam packaging, aerosol spray cans, and as the coolants in refrigerators and air conditioners. Since 1987, The Montreal Protocol outlawed the use of CFCs in the United States and many countries. Even if all countries quit using CFCs, however, they will linger in the upper atmosphere for decades. UV light is also monitored, which indirectly reflects the condition of the upper atmosphere ozone layer.
Weathering is the physical breakup of rocks, and is often confused with erosion, which is the removal of rock by gravity, wind, and water once it has weathered. This confusion is understandable because they are often intertwined. There are two types of weathering: physical and chemical. Physical weathering breaks the rock into smaller pieces, but the components remain virtually the same. An example might be ice expanding a crack on the side of an arch. Each time the water freezes, the crack gets bigger, but both pieces are still sandstone. Eventually, the piece falls out of the arch, which is erosion. The piece is still sandstone, just smaller and no longer connected to the arch.
Chemical weathering involves breaking down of the minerals that hold the individual grains of sand together. On the Colorado Plateau, this breakdown is often caused by rainwater, picking up CO2 in the atmosphere and becoming slightly acidic. This weak carbonic acid reacts with the calcium carbonate in the stone, slowly eating away at the rock. Chemical weathering dissolves approximately one sand grain per year from the rock. Wind and rain then removes these tiny grains. In places on the stone where water stands, this process speeds up, causing depressions to slowly deepen. Thus, desert potholes grow deeper over time.
PH is the measurement of hydrogen (H+) and hydroxyl (OH-) in a solution that contains water. The pH scale is typically measured from 0 to 14. A substance with a pH of 7 is a neutral solution, having equal numbers of H+ and OH- ions. Solutions with more H+ ions are acidic and will have a pH between 0 and 7. Solutions with more OH- ions are basic and will have a pH between 7 and 14. pH will increase or decrease when the proportions of each ion change as solutions react with other substances. An acid mixed with a base will neutralize both solutions and bring the pH closer to 7.
Essential Questions: What is matter? What is the difference between a physical change and a chemical change in matter?
flask, spoon, eye protection, vinegar, baking soda, tray, Quizlet login. paper, mini- marshmallows, toothpicks, 2 water molecule models, 2L plastic bottle, rubbing alcohol, cork, bike pump with needle, vitamin c solution (1000mg per 2 oz. distilled water), glass jar, tincture of iodine; evidence of physical and chemical change cards.
1) Ask students to define matter. Explain that matter is defined as anything with mass and volume. Matter can be large or small and you may or may not be able to touch and see it, even with the aid of a microscope. Have students list some things that might be matter (i.e. books, desks, themselves, air, water, bugs, etc…). Tell students all matter is made up of tiny molecules, and molecules are made up of even small things called atoms. Discuss that a model is a copy of something in the real world that is bigger (or smaller) so we can observe it. Show students a model of a water molecule. Ask students if they have ever heard of water called H2O and use the model to describe the reason for this name. (2-3 min)
2) Tell students they are going to make water molecule models. Hand out 4 toothpicks and 6 marshmallows to each student. Demonstrate making water molecules by asking students to place two toothpicks in one marshmallow in a v shape and then add marshmallows to the other ends of the toothpicks. When they finish, have them make a second molecule. (2-3 min)
3) Remind students that matter exists in three states and see if they can name and define them. Liquid is a substance with definite volume but changes shape to fit its container. Demonstrate how water molecules move around each other with your models. Have students hold one model in each hand and act out liquid water with their models. A gas is a substance that has neither shape nor definite volume. Demonstrate how molecules move around as a gas. Have students act this out, being careful of their neighbors. A solid is a substance with a definite volume and shape. Once again, have students demonstrate. Describe these changes to matter as physical changes. Call out random states and having students act them out. Afterwards, discuss if the molecules ever changed. Tell students that a physical change to matter occurs when the molecules do not change. The substance might change how it looks, but not what it is made of. It is basically the same stuff. (2-3 min)
4) Chemical changes to matter occur when the molecules get broken up and come back together in new and different combinations. Demonstrate with the plastic water molecules. Have all the students reorganize their molecules and show them to their neighbors. (2-3 min)
5) Tell students that since molecules are too small for us to see, we have to look for evidence of a change to know if a physical or chemical changes occurred. Write “Evidence of physical changes” on the board. List and demonstrate a few examples. Shape change: crumpling paper. Size change: tearing paper. (2-3 min)
6) Demonstrate a change in state by bringing out a plastic bottle containing one teaspoon of rubbing alcohol and stoppered with a cork. Using a ball needle and a bike pump, add pressure to the bottle. (4 or five pumps). When you pull the cork, the pressure is suddenly released, causing a cloud to form in the bottle. Explain that the liquid inside is still alcohol, adding pressure to the bottle caused the alcohol vapor molecules to compress together. When the pressure was released, the vapor expanded quickly and cooled, causing it to condense into a cloud. This is a physical state change from gas to liquid. (2-3 min)
7) Remind students that chemical changes create new substances. Chemical changes can usually be detected with our senses. Write “Evidence of a chemical changes” on the board. List and discuss examples. A new substance is created: frying an egg or baking a cake. Light is emitted: fireworks. An unexpected color change: rust. Heat is released or absorbed: cooking, heat from a campfire. Gas is released without boiling: adding baking soda to vinegar. A solid comes from a liquid without freezing: milk curdling. A change in smell or taste: fruit rotting. (2-3 min)
8) Show students a solution of vitamin C and water. Next, show students the iodine, discuss its uses and ask several students to describe its color. Drop one teaspoon of iodine into the vitamin C solution and observe the color change. Discuss evidence they might observe of a chemical change. Include the difference between an expected color change (like mixing paint) and an unexpected color change from a chemical reaction. (2-3 min) (you can delete this experiment if we are running low on time)
9) Tell the students they will try to figure out changes in matter. Give everyone a change card. Have the students look at the cards and identify how the object or objects were changed. The students should then turn to their partner and share their card and conclusions. See if the partner agrees. Pass the cards to another group and repeat until time is up or cards have gone around the room.
Or – Place cards under the document camera and discuss what is happening in each card as a class. (if time is short, do this option)
10) First, discuss easy to understand examples. Have students name them. Next discuss examples that were more difficult. Use evidence of changes written on the board to help students decipher what is happening as a substance changes. Tell the students that during the upcoming field trip, they will be looking at physical and chemical changes in matter in the real world. Have students list the things they will need to remember to bring for a winter field trip. Write the list on the board. (3-5 min)
a. Students will be able to define physical and chemical weathering of rocks.
b. Students will be able to name one agent of physical weathering.
c. Students will be able to describe a sign of chemical weathering.
Essential Question: How does physical and chemical weathering change sandstone?
small pieces of chalk (some pre-crushed); weathering flip book; coke; lemon juice; vinegar; pothole photo; microscope sandstone photos; acidity level chart; metal cups (1 per student), slosh bucket, molecule model (CaCO3). Evidence of change posters.
1) Have the students look at the view across the landscape towards the road. Point out the Neck and the steep cliffs on each side. Ask the students what geologic processes create this landscape. When students mention weathering and erosion, ask them what will eventually happen to the Neck. Remind the students that weathering and erosion change rocks over time. Weathering is the physical breaking up of rock into smaller pieces. To demonstrate, take a small piece of chalk and have a student smash the chalk. Next tell students erosion is the removal of the rock. To demonstrate, have a different student pour water on the chalk so it washes away. To create Canyonlands, the type of matter changing is sandstone. Tell the students that to understand what might happen to the sandstone on a big, landscape-sized scale, we need to examine sandstone on a smaller scale. (3 min)
2) Have the students find two palm size rocks and instruct them to rub the rocks together and observe what happens. As the students weather their rocks, discuss how the pieces falling off are still rocks, only smaller. Their actions are similar to changes happening at Canyonlands only on a smaller/faster scale.
3) Discuss the two types of weathering. Physical weathering results from a physical change in the sandstone; chemical weathering refers to a chemical change in the sandstone. Discuss evidence of physical changes and have students predict how this might occur with rocks. Tell the students they are going to investigate types of physical weathering that can occur. Use the physical weathering flipbook as a guide for examples. Tell students they weathered their rocks through a process called abrasion. Have students test gravity and impact by throwing their rocks from the cliff. Discuss how the resulting bits of rock are still sandstone, only smaller. Show the tree root prying rocks apart and discuss. (7 min)
4) Tell students chemical reactions also weather or break apart sandstone. They are now going to investigate chemical weathering. To understand chemical weathering, it helps to think about sandstone on an even smaller scale. Show the microscopic picture of sandstone. Point out the two main ingredients of sandstone on the picture: sand grains and the “glue” that holds the sand grains together. Tell students chemical weathering very slowly dissolves this “glue”. In the atmosphere, water reacts with gasses such as carbon dioxide to make it slightly acidic. Show students the acidity level chart and discuss the acidity level of various substances. (5 min)
5) The slightly acidic water reacts with and breaks down the “glue”, causing the grains to be blown or washed away. It is a slow process. Rock weathers at a rate of about one sand grain a year. It happens faster in places where water stands, such as in depressions or potholes. Show students the pothole picture and ask if they have ever seen a water filled pothole with bubbles on the bottom. Use the chemical changes poster to review evidence of chemical changes and discuss the cause of those bubbles. Ask students if they think a slightly stronger (stronger than rainwater, but still safe to touch) will allow them to speed up the reaction even more?
6) Have each student find a rock no bigger than a fingernail to test and choose which acid they would like to investigate (vinegar, lemon juice, Coca-Cola). Give them each a metal cup and pour the liquids into the cup so they just cover their rock.
7) Discuss observed evidence of chemical changes. They should observe a few bubbles and maybe some sand grains falling off the rock. Ask students to share their experiments with their classmates and discuss. Notice how white rocks tend to bubble more than red rocks, encourage students to theorize why. (5 min)
8) Give one student with each acid piece of chalk to drop in the liquid. Explain that chalk is the same type of matter as the glue in the sandstone. Look for evidence of chemical changes. When students talk about the bubbles, ask what they think is happening. The chalk is breaking down and becoming a new substance with different properties. In this case, chalk breaks down into carbon dioxide, which is a gas at most normal temperatures, therefore, we see bubbles. Use the plastic atom molecules to model this reaction taking place. (5 min)
9) Dispose liquid in the slosh bucket. Review how both physical and chemical weathering on a small scale create the landscape we see on a large scale over long periods of time. Challenge the students to find evidence of weathering on the hike back to the bus and throughout the rest of the day. (2 min)
Objectives: Students will be able to:
a. Describe what a molecule is.
b. Explain how the ozone experiment at Canyonlands fits into the scientific method.
c. Describe what type of reaction physical or chemical is causing ozone depletion.
Are large scale environmental problems solvable by small actions?
molecule models; clipboard with paper and pencil/marker; map of ozone hole (Berman, 2002; Ozone health effects chart; current low level ozone map (retrieve from www.airnow.gov), Picture of Moab on a fire day.
1) Ask students if they can describe matter. Remind students of the models they built in the pre-trip. Have students look at the La Sal Mountains and discuss how beautiful they are. Show students the pictures taken in Moab on clean and dirty air days. Tell students both photos were taken from the same place during the summer of 2020 and ask students to speculate about what’s happening? The second picture was taken on a day when western wildfires filled our air with smoke. (2-3 min)
2) Tell students one of the molecules in smoke is ozone. Show students a model of an ozone molecule. At Canyonlands, scientists are using the ozone molecule to learn about air pollution. Review the detrimental effects of lower atmosphere ozone and where it comes from. Discuss the chemical reactions that create lower-level ozone (pollution) and make it harmful to living creatures (it reacts with carbon). Ask students if anyone had a difficult time breathing during the smokey days in Moab, or if anyone ever visited a big city with bad air. Moab usually has some of the cleanest air in the country, so scientists are measuring our air right here, right now. They are asking the question “How do the levels of ozone in our atmosphere differ from place to place and over time.” We are the control part of the experiment. The part where scientists learn how much ozone is naturally in clean air, so other places have something to compare to. Tell students they get to see this science experiment in action. (2-3 min)
3) Show students the map of ozone monitoring locations. Every day, the EPA uses the results of their experiments to produce a map of ozone in the air so people know how to stay healthy. Discuss how this information is used by the average person by comparing the PPM number to the health effects chart. Compare different levels of AQI in relation to what kids can do or not do at recess. Have students predict what how much ozone is currently in the air. (2-3 min)
4) Show students the current amount of ozone in the air. Read the number, including the decimal and PPM. Show the current lower-level ozone map as the results of the experiment. Discuss places with bad air. Show students the ozone map produced on the wildfire day shown in the opening photo and let them find Moab.
5) Have students repeat after you with actions. “Ozone.” Hands out wide. “Bad nearby.” Hands up high “But good up high.” Repeat several times. Ask students if they have ever heard of ozone being a good thing? (1 min)
6) Ask students if they have ever heard of ozone being a good thing. On a piece of paper, draw the ozone layer as a “blanket” around the Earth. Discuss the benefit of the ozone in the upper atmosphere (i.e. blocking some of the sun’s ultraviolet (UV) rays, protecting us from skin cancer, etc.). (5 min)
7) Remind students that in a chemical reaction, the atoms in a molecule break apart but do not disappear. Explain that many years ago, humans produced a chemical that reacted with ozone molecules in the upper atmosphere. Use a molecule model to explain how CFCs rose to the upper atmosphere then broke apart. Have students pretend to be oxygen atoms and link arms to become ozone molecules. One kid will play the part of Charlie Chlorine. As the students act out how chlorine breaks up ozone, tell a story about how each of the atoms interacts. Emphasize that this is a chemical reaction because the molecules are breaking apart, but that the atoms never go away. (5 min)
8) Tell students that in the fifty years or so it will take Charlie to link up with a hydrogen and drift back to the earth’s surface, he can do a lot of damage to the ozone layer. Discuss that while this damage is happening now, humans realized what was happening. The world came together and stopped releasing CFCs into the atmosphere. Now the Ozone layer is recovering. In the meantime, we all need to wear sunscreen. Relate the story as one of success (we are solving a huge problem), rather than one of failure (we created a huge problem.)
9) Play Ozone Depletion Tag with as many students, teachers, and parents as you can round up. Review the beneficial properties of upper atmosphere ozone. Explain that CFCs destroy this ozone. Define boundaries. Have each participant pick and secretly read one card to determine which upper atmosphere gas they will be. Have participants return their cards and inform them one of them is a CFC while the rest are ozone. Ask students to spread out, floating in the upper atmosphere. Instruct them that when you say, “go,” the CFC should destroy ozone by tagging them. Once an ozone is tagged, it acts as a free radical chlorine and may tag other ozones. It doesn’t take long until the ozone is gone. Play two or three rounds. If time, play an additional round where a student plays a hydrogen. They should say “untag” tag the CFCs. Untagged students return to being ozone molecules.
Students will be able to:
a. Describe the difference between chemical and physical changes in matter.
b. Name one chemical and one physical change that can be observed at Canyonlands National Park.
Essential Question: What physical and chemical changes occur in nature?
Physical and chemical change sheets. Paper and clipboard or whiteboard and dry erase marker.
1) Take the bus with the students to the trailhead. Once on the trail, stop and explain to students that as they hike, they will search for physical and chemical changes to matter in nature. Ask students to describe matter and use the change sheets to define physical and chemical changes and remind students of evidence they might observe. Challenge students to see how many changes they can find.
2) As you hike, have the first person in line point out an example of a physical and chemical change they observe in nature. Have all students guess which change is happening by making a ‘P’ or ‘C’ symbol against their chest. Discuss and explain the evidence and reasoning behind each type of change. Switch leaders and continue. Add in other examples. (i.e. plants absorbing nutrients out of the ground, plants changing carbon dioxide into oxygen, photosynthesis, animals eating plants, animal scat, animal tracks, erosion of rock, creation of the canyon and arch, snow melting, and sand transportation).
3) After hiking half your allotted time, stop and gather the students. Have students list the changes they remember. Record the group’s observations as a list and discuss.
4) Hike back to the bus.
Examples you can discuss include:
- Cryptobiotic Soil Crust filaments forming clumps – Sand sticks to the cyanobacteria, which holds it in clumpy shapes, but individual sand grains do not change
- Washes next to the path – water carries sand grains away, but those grains are still sand
- Sand and gravel in the path
- Footprints or animal tracks in the sand – Sand is moved around, but the individual sand grains do not change
- Cairns on trail - Humans moved these rocks, but they are still rocks
- Animal holes - Sand is moved around by the animals but it remains sand.
- Arches forming - Rocks that fall away and increase the opening of an arch are smaller pieces of the same rock
- Branches falling off trees/ branches lining trail - The wood is no longer connected to the living tree, but it remains wood
- Rocks breaking away from other rocks – New rocks are smaller, but remain rocks
- Pine cones/needles dropping from the tree
- Rain falling from the sky – When water falls as rain, it changes from a gas to a liquid, which is a change in state. It is still water.
- Snow in the mountains melting – Snow melting from a solid to a liquid is a change of state. It is still water.
- Digestion - Digestion breaks down food and creates waste. Digestion is a chemical change because chemicals (including stomach acids and enzymes) in your stomach and intestines break food into simpler molecules. Evidence of this change we often notice include: a change of smell, color, or that the waste left behind is a new substance.
- Animals eating and digesting pine nuts
- Berries /leaves/ logs rotting or decomposing into smaller organic matter – decomposers like bacteria and insects digest once-living material creating waste. (a new substance)
- Wood beetle eating trails in the logs
- Animals eating berries/nuts/leaves/seeds
- Photosynthesis – Plants use the sun’s energy to break carbon-dioxide and water molecules and reform them into sugar and oxygen molecules. Since new substances are formed, photosynthesis is a chemical change. We see evidence of photosynthesis in the growth of plant parts, such as new leaves and stems. Living things get bigger because new cells are created. In addition, the green color in leaves is the sugar produced by photosynthesis.
- Water poured on dormant moss, turning it green – Moss turns green as it begins to photosynthesize and produce chlorophyl
- Cryptobiotic soil growing and fixing nitrogen – Cyanobacteria uses photosynthesis to grow. Growth is chemical change because something new is created. In addition, one of crypto's most important jobs is to pull nitrogen molecules from the air and break them apart so plants can absorb the individual nitrogen atoms.
- Pine trees growing pinecones
- Juniper berries growing berries
- Leaves turning green through photosynthesis, turning red/yellow when photosynthesis stops
- Yuccas growing flowers
- Cacti growing spines
- Chemical Weathering - Rainwater reacts with and dissolves the glue holding the sand grains together (calcium carbonite). This reaction produces a gas. Sand grains then are released and blow away. This is a very slow process, breaking down the rocks only the depth of one sand grain a year.
- Potholes are holes in the sandstone bedrock
- Arches getting larger
- Natural holes in the sandstone wall
- Combustion – When once-living material is burned, carbon combines with oxygen in the air. This reaction produces heat and light humans can use. Often, a new substance is discarded as waste. (i/e ash, smoke, exhaust)
- Airplanes/Cars flying overhead or driving along the road – Engines burn fuel, creating heat, which we have harnessed to power engines
- Burned tree limbs – evidence combustion occurred
- Oxidation – When a substance combines with the oxygen in the air. The evidence we often see is a color change.
- The red color of the surrounding sandstone– the iron in the rocks is rusting.
Objectives: Students will be able to:
a. Observe properties of matter.
b. Look for evidence of a chemical change.
Essential Question: How do we know if a new substance is created when combining two substances?
24 cups; 12 jars; balloons; signs of chemical change poster; magnets for white board; experiment cards; vinegar**; baking soda; cola**; milk of magnesia**; active dry yeast, hydrogen peroxide**, strainer, temperature guns, 12 trays; extra cabbage juice indicator; safety goggles(one per student), Matter Investigation worksheets
**Pre-mix liquids with cabbage juice indicator before giving to students. To make cabbage juice indicator: Chop up a red cabbage, boil in water for 20 minutes or until the water is dark purple. Strain the liquid into a container; keep the liquid.
1) Review the information students learned on the field trip. Ask if they can remember some physical and chemical changes to matter, they observed in nature and what evidence they saw. Tell the students they are going to investigate chemical changes in matter by conducting experiments. Review the definitions of physical and chemical changes and use the chemical change poster to describe evidence that a chemical change has occurred. Have students name examples of each type of change.
2) Remind the students that when chemical changes occur, new substances are created, and these new substances have different properties. Name some properties of matter such as state at room temperature, density (whether it sinks or floats), and color. Tell the students we will be looking at 2 properties of matter in our experiments: its state at room temperature and its color. We will also be measuring the temperature of the substances to see if it changes throughout the investigation.
3) Demonstrate the investigation by mixing vinegar and milk of magnesia. First, show the students the Matter Investigation worksheet with the document camera. Make a prediction on the worksheet and then record the properties of each substance and the temperature using the temperature gun. Show students how to quickly put the balloon on the top of the bottle to catch any gases that might form. Mix the ingredients, add the balloon, and have the students observe any changes. Record observations on the worksheet and have the students determine if a new substance was formed. Did the properties change? Did we see any other evidence? Remind students bubbles are a sign a chemical change has occurred because a gas was formed. In this experiment, those bubbles would then rise in the liquid and be trapped in the balloon.
4) Divide the class into pairs. Hand out Matter Investigation worksheets and experiment cards. Have the students predict the results of the experiment, discuss, and record their hypothesis. One student from each pair will then retrieve a tray of supplies: two cups with their two substances (cabbage indicator pre-mixed into liquids), bottle, balloon, temperature gun. Have students record the properties and temperature of each substance before mixing, mix the substances, add the balloon, and then record observations after the experiments.
5) When the students have finished their experiment, have them bring the tray with all the supplies to the back of the room, clean out the bottle, and throw away the balloon if dirty. Tell them to keep the Matter Investigation worksheet and discuss conclusions with their partner. If a group finishes with time left, they may do a bonus experiment, choosing their own ingredients.
6) Have groups present their experiments to the class. Students should explain what they mixed and their conclusions: did a chemical change occur? What was the evidence? Remind students that what we observed today isn’t the only evidence of chemical changes. Ask them what kind of evidence of chemical changes they might find in their everyday life.
References and Resources
Fluegelman, A. (1981). More new games!…and playful ideas from the new games foundation. Tiburon, CA: Headlands Press.
Levine, J. S. (1992). Ozone, climate, and global atmospheric change. Reprint from Science Activities 29, no. 1: 10-16. Washington, DC: Heldref Publications.
Jordan School District and the Utah Office of Education. (2002). Elementary science teacher resource book: State science core teacher text. Salt Lake City, Utah: Utah State Office of Education
National Park Service and National Biological Survey Colorado Plateau Research Station at Northern Arizona University. 1994. Where
the earth is the floor of the sky: Visibility on the Colorado Plateau. Brochure. U.S. Government Printing Office.
National Park Service, Minnesota Environmental Education Board, and the National Parks and Conservation Association. (1989). Biological diversity makes a world of difference. Washington, DC: National Parks and Conservation Association.
Peterson, M. F. (1973). Activities for environmental education: Water, air, soil. Bismark, ND: Department of Public Instruction.
Sherwood, E.A., Williams, R.A., & Rockwell, R.E. (1990). More mudpies to magnets. Rainier, MD: Gryphon House Press.
Storer Camps. (1988). Nature’s classroom: A program guide for camps and schools. Martinsville, IN: American Camping Association.
Last updated: April 8, 2022