Part Two Our Ever Changing Earth Grade Level: 1 *Part Two is actually a unit plan and contains more than one lesson. You can pick and choose those that best fit your goals and the ability level of your students. Purpose: Our earth is constantly changing. The earth is not a single, solid sheet. It is made up of many continually moving plates that are deep within the earth. These plates float on a layer below the earth s solid crust that is soft and moveable. It provides a lubricating layer over which the crust can move. Sometimes magma is formed in the hot mantle and rises through the spaces between the plates. Cooler, heavier rock may be sinking down at the same time. This movement hot mantle material keeps the plates moving. The movement of the plates causes changes at the surface of the earth. When plates collide, sometimes one gets pushed under another causing it to be closer to the heated core of the earth. Part of the plate may begin to melt causing more magma to be in an area. This magma may push through to the crust and cause a volcano to erupt. A volcano is a builder of the earth s surface. Many landforms we think of as mountains are extinct volcanoes. Plates sometimes get caught on each other. Great pressure is built up as they try to get past another. When they finally push past another, this pressure is released and causes an earthquake. As the plates move, they may open up cracks at the surface of the earth during an earthquake. Mountains are formed as plates bump into each other and the pressure exerted by the movement pushes up the sides that collide. Mountains and volcanoes are the builders of the earth s surface. Goals for Our Ever-changing Earth: 1. Students will be introduced to plate tectonics. 2. Students will observe the forces of erosion. 3. Students will observe the forces of weathering. Targeted Objectives for Our Ever-changing Earth: 1. Students will be able to state three ways in which the earth changes. 2. Students will be able to record observations and come to conclusions about what they ve observed. 3. Students will be able to verbalize the difference between erosion and weathering. 1
Demonstration Spongy Earth Thin sponges Permanent marker Large aluminum pan Dampen several large thin sponges. You may want to draw lines on the side of the sponge with a permanent marker to show layering within the earth. Gently move two sponges around to demonstrate how the plates under our earth move around. Bump the two sponges gently into one another. What is happening now to our plates? What would happen if the two sponges were pushed harder? What do we call the force that is building as the sponges push against one another? These plates can move different ways when they bump against one another. Demonstrate how one may move under the other. When this happens, how do the plates move? What kind of change on the surface of the earth could that cause? A crack caused by the earth breaking is called a fault. Another way these plates can move is to bend. Bend one of the sponges by pressing on opposite ends of the sponge. When this occurs what changes may be noticed at the surface of the earth? Demonstrate two sponges getting stuck on each other and then the pressure built up forcefully moving them in a sideways movement. What could occur on the earth s surface when this happens? Sometimes the pressure actually folds the plate over onto itself. What would happen at the earth s surface during this event? Students should be asked to draw pictures of the plates or sponge in their science notebooks after each demonstration. They should write several sentences describing what occurred in the demonstration and what could be the result on the earth s surface. Place the sponges in a science center so that the children can recreate these demonstrations themselves. Investigation Plate Movement Have children pretend that their hands are the plates buried deep inside the earth. Ask them to place their hands side by side pressing them together very hard. Then ask them to slide one hand ahead of the other. This movement demonstrates the plates moving past the other. Ask them to describe how the hands moved. Was it hard or easy to move a hand? Did it move in a smooth or jerky motion? Now ask them to link the fingers of one hand with the fingers of the other. Try to pull their hands apart without the fingers trying to let go. What do they feel as the hands separate? Earthquakes also occur when the plates pull apart from one another Investigation The Rubber Band Rubber bands Use a rubber band like a slingshot to demonstrate the force that is created when something has pressure exerted on it. Does the rubber band move an object when it is 2
lying on a table? What must be done to the band to create force? Ask children to compare this force to the force that is exerted on the plates beneath the earth. Demonstrations Pumice Candles Matches Saucepan Heat source (burner) Ice Large aluminum pan Review the idea that melted rock, called magma, flows from volcanoes as lava. The rock is melted inside the earth. Light a candle to demonstrate that although the candle is a solid, heat can change the wax of the candle to a liquid. Cut up the candle and melt the pieces in a small saucepan. Pour the melted wax into a pan of cold water. You may want to add ice to the water to get it really cold. As the wax falls into the water it hardens. Allow the children to feel the wax after it hardens in the water. Sometimes the magma from a volcano falls into the ocean in the same way the wax fell. Ask the children to describe how the lava is similar to the wax. Rock formed in this way is called pumice. Weathering and Erosion As soon as the earth built itself up, two new forces begin their work. These two forces are weathering and erosion. These forces work to break up the rock that has been formed. The fact is that the higher, more jagged a mountain is, the faster these forces work on them. Rock seems to be such a hard substance that it should never be changed, but that is not true. Weathering breaks the rock down into smaller fragments, and erosion, which we shall look at next, moves the fragments of rock from one place to another. There are two types of weathering: physical weathering and chemical weathering. Both may be happening at the same time. An example of physical weathering is where water freezes, expands, and opens up cracks in the rock surface. Wind is another example of physical weathering. Wind can move sand from one place to another or blow it against hard surfaces rubbing away at them like sandpaper. Chemical weathering changes the minerals that make up the rock. The most common agent of chemical weathering is rainwater. Carbon dioxide gas in the atmosphere dissolves in the rain, forming a weak acid called carbonic acid that slowly dissolves some of the minerals in the rock. Erosion is the process by which rock and other materials of the earth s crust that have been broken down by weathering are carried away by natural agents, such as water, wind, ice, and gravity. In this movement, more wearing away of the rock occurs by the transported particles. Floods cause 3
erosion very quickly carrying topsoil away very quickly and bumping rocks against other rocks or landforms. A fast stream can cut into rock and create very deep canyons. Weathering Investigation Freezing Small jar Freezer baggie Access to a freezer Fill a baby food or other small jar with water. Place this in a bag. Put this in the freezer overnight or until solidly frozen. Remove and examine. What has changed about the jar? What was in the jar? What change occurred to the water when it was frozen? Like the jar, rocks get broken or cracked when water gets frozen in the cracks. The cracks may be small at first, but over time more and more water can get into the cracks causing the cracks to enlarge each time. In time this may completely split the rock. Students should write about this investigation in their science journal. Weathering Investigation Freezing Clay Clay Freezer baggie Access to a freezer Roll a ball of clay. Wet the clay. Place the ball of clay in a plastic bag and then put the bag into the freezer. When you take the clay out of the freezer, its surface will be cracked and broken. Wet the ball and return it to the freezer. Each time it is removed, the cracks get larger. What has changed about the clay? How is the clay like rocks during winter? Students should write about this investigation in their science journal. Weathering Investigation Rock Rust Steel wool Saucer 4
Wet a piece of steel wool (without soap) and place it on a saucer. Allow it to sit for several days. Observe the steel wool. What changes do the children see in the wool? Parts of the steel wool seem to have turned into a red powder. Oxygen combines with the iron in the steel wool pad, forming rust. Rocks with iron that are at the surface of the earth react with moist air and eventually crumble away as did the steel wool. Weathering Investigation Chalk Chalk Vinegar Place a piece of chalk in vinegar. Chalk is made of limestone, so it reacts to the acid in the same way. Carbon dioxide is given off in the form of bubbles. Acid rain affects buildings and statues in this way. This affects some stones more slowly than limestone. Weathering Investigation Sand Paper Sand paper Wood scraps Rub sandpaper over a rough area of wood. What happens to the sandpaper? What happens to the wood? How does sand rubbing rock affect the rock? How does sand rub the rock? Students should record the results of this investigation in their science notebook. Weathering Investigation File Away Steel file Pencils Rub a file against the edge of a pencil. Why does the file rub the wood off the pencil? How is sand that hits rock like the abrasive edge of the file? Students should record this investigation in their science journal. Weathering Investigation Dust in the Wind Distilled water Gallon glass jar Place a quart of distilled water in a gallon jar. Explain to the children that distilled water has no impurities in it. Put the jar outside about five feet off the ground and in a place where it will not be disturbed for thirty days. Check the jar frequently to add more water 5
as it evaporates. At the end of the thirty days, pour the water into a pan and begin to boil off the water. What is left in the pan? Where did it come from? Just as children feel dirt blowing and stinging their faces during a strong wind, dust is being moved from one place to another all the time. Erosion Investigation Sand Castles Sand Straws Leaf blower (optional) Access to outdoors Have children build sand castles or small piles of sand outside. Children can blow through a straw at the piles. What happens to the sand? How far does it travel? How does this relate to erosion? For a really exciting investigation, use a leaf blower to blow the sand. The sand will be moved much faster and farther than in the first method. Record the results of this investigation in the science journal. Erosion Investigation Drip Shallow baking dish Soil Small pebbles Book Paper cups Leaves Have students fill a shallow baking dish with soil and small pebbles. Set this on an incline by placing books under one end of the dish. Using a paper cup with small holes poked in the bottom, have the children begin dripping water from the cup on the upper end of the dish. Keep the water dripping until the soil and rocks begin to slip to the other end of the pan. Vary this investigation by increasing or decreasing the angle of the baking dish. You may want to have two dishes at different inclines at the same time, so that the children can do side-by-side comparisons. How does the angle of the dish affect the investigation? Using two baking dishes filled with soil, cover one of the dishes with leaves. Sprinkle the water. Does covering the soil affect the amount of erosion? Children should record the results of this investigation in their science notebooks. Erosion Investigation Stream Paths Baking dish Small rocks 6
Soil Book Paper cups Fill a baking dish with soil. Place small rocks at spots in the soil that will impede the flow of water. Put books under one end of the dish to create an incline. Using a paper cup with holes poked in the bottom, drip water from the cup onto the soil. Where does the water flow? How do the rocks change the path of the water? Have children brainstorm ways that this investigation is like rainwater falling and moving along the earth? Erosion Investigation Cuts Bar of soap (from a faucet) [Alternative recycling dripping water using 2-liter bottle, plastic tubing, and attachment] Place a bar of soap under a faucet. Turn the water on to a moderate flow of water. Let the water run for forty-five to sixty minutes. How did the running water affect the soap? How would water dripping on rock affect the rock over many years? Erosion Investigation Dissolving LifeSavers (candy) Baby food jars (or paper cups) cold and hot Pass out one lifesaver to children. Place one lifesaver in a glass of cold water and another in a glass of hot water. Allow the children to suck on the candy to prove that it will dissolve. Tell them that they are not to chew on the candy. Children will raise their hand when their lifesaver is gone. Brainstorm ideas about what affected the dissolving of the candy. How did the rate of speed compare with the candy placed in the jars? Did they rub it with their tongues? Did the heat of their body affect the rate? What could they do to make the candy in the jars dissolve faster? The use of stirring and different liquids could affect the rate. Compare how the lifesaver is like a rock. How are the forces that change rock similar to the lifesaver? Assessment of Our Changing Earth 1. Children should tell or write short sentences telling three ways the earth changes. 2. Science journals should be collected and graded according to the description of the investigations and learning derived from these investigations. 7
3. There are rubrics that can be adapted for your use in any of the above activities. Check out these sources: http://www.stclair.k12.il.us/services/scilit/invsrbr.htm http://www.stclair.k12.il.us/services/scilit/hlsticrb.htm http://www.exemplars.com/science_rubric.html http://www.col-ed.org/smcnws/scientific.html Illinois State Board of Education Goals and Standards: 3.B.1a: Use prewriting strategies to generate and organize ideas (e.g., focus on one topic; organize writing to include a beginning, middle and end; use descriptive words when writing about people, places, things, events). 11.A.1a: Describe an observed event. 12.E.1b: Identify and describe patterns of weather and seasonal change. Print Resources National Wildlife Foundation. 1989. Geology The Active Earth. Philadelphia: Chelsea House Publishers. Jennings, Terry. 1989. Exploring Our World: The Earth. London: Oxford University Press Silver, Donald M. 1989. Earth: The Everchanging Planet. New York: Random House. Challond, Helen J. 1982. Activities in Earth Science. Chicago: Children s Press. O Donaghue, Michael. 1994. Rocks and Minerals of the World. San Diego: Thunder Bay Press. Parker, Steve. 1993. Rocks and Minerals. New York: Dorling, Kindersley. Web Resources Explorer Many lesson plans for the natural science curriculum. http://unite.ukans.edu/ 8
American Museum of Natural History Rose Center for Earth and Space Information on earth science, rocks, and minerals. www.amnh.org/rose/hope/ About - Geology Topics Many links to information and pictures about earth science, rocks, and minerals. http://geology.about.com/ USA Today Weather and climate information for teachers and earth science lessons. http://usatoday.com/weather/wteach.htm Rocks for Kids www.rocksforkids.com Science Teacher Stuff Resources for K 12 Teachers www.scienceteacherstuff.com/kidstuffearth.html University of North Dakota Volcano Info Legends section http://volcano.und.nodak.edu/vwdocs/kids/legends.html Fourth and Fifth Grade Virtual Library Earth Science Links http://www.learning.caliberinc.com/earthsci.html Mrs. Mitchell s Virtual School Earth Science Links www.kathimitchell.com/earthsci.htm 9