Weathering Gizmo Answer Key

Name: Lesly Terrell Date: 03-25-2022 Student Exploration: Weathering Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: abrasion, chemical weathering, clay formation, climate, dissolving, frost wedging, granite, limestone, mechanical weathering, rusting, sandstone, shale, weathering Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Compare the two pictures at right. Both pictures show the same kind of rock, granite. 1. Which rock do you think has been exposed on Earth’s surface longer? B 2. Why do you think so? Rounded and worn edges, and smooth. Gizmo Warm-up When rocks are exposed on Earth’s surface, they are gradually broken down into soil by the actions of rain, ice, wind, and living organisms. This process is called weathering. In the Weathering Gizmo, you will explore how weathering takes place. To begin, select the SIMULATION tab. Notice the selected Rock type is Granite, a hard, dense rock. 1. Click Play ( ). Wait for about 5,000 simulated years, and click Pause ( ). What do you notice? Very little 2. Click Fastplay ( ). Wait for about 50,000 simulated years. What do you notice? Very little 3. Based on your observations, is weathering a fast or slow process? It’s a slow process Activity A: Types of weathering Get the Gizmo ready: ● Select the ANIMATION tab. Check that Frost wedging is selected. Introduction: Mechanical weathering occurs when rocks are physically broken or worn down. Chemical weathering occurs when the minerals in the rock are changed by chemical reactions. Question: What are the most common ways in which weathering occurs? 1. Observe: Read the text about frost wedging, then click Play. A. In the process of frost wedging, how does ice cause cracks in rocks to become larger? Water expands when it freezes in cracks, widening the fissures. B. Is frost wedging more important in a warm or a cold climate? Cold climate 2. Observe: Read about and look at the animations for the other major types of weathering: Abrasion, Pressure release, Dissolving, Clay formation, and Rusting. A. What are three different ways that rocks can be worn down by abrasion? Small boulders and stones pulled by glaciers, wind-borne sand, water-borne sediment, or even the footwear worn by animals while moving. B. How can a large block of granite form layers like an onion? When Granite is exposed at the surface, it is under much less pressure than where itwas when it formed deep beneath the Earth. This pressure release allows the rockto expand, causing it to crack and flake off in layers, like an onion. C. What type of rock is affected by dissolving, and what features result? When carbon dioxide and rain combine, limestone dissolves. This creates sinkholes, underground streams, and caverns. D. How does clay formation affect a rock? Clay may expand when it becomes cold and absorbs water. The rock can shatter when it transforms into clay when exposed to water. E. Which part of a rock will undergo rusting? Iron in rocks rusts. 3. Fill in: Scientists use the terms “oxidation,” “carbonation,” “hydrolysis,” and “exfoliation” for different types of weathering. Fill in each blank with the appropriate term. Pressure release: Exfoliation Clay formation: Hydrolysis Dissolution Carbonation Rusting: Oxidation 4. Observe: Select Other. Read the descriptions of each type of weathering, then match each to its description below: A. Weathering from chemicals produced by colonies of algae and fungi. Heat expansion B. Weathering that occurs when crystals grow. C Root weathering C. Weathering caused by the growth of trees. A Lichen growth D. Weathering common in desert climates. B Salt weathering D 5. Categorize: List all of the types of mechanical weathering you have learned about in the left column of the table, and all of the types of chemical weathering you have read about in the right column. Mechanical weathering Frost wedging Salt wedging Pressure Release (Exfoliation) Root Wedging Abrasion Chemical weathering Rust Clay formation Algae and Lichen Dissolving (Carbonation) 6. Interpret: Based on the descriptions and images, guess which type of weathering is shown by each of the images below. Explain each answer. “Honeycomb” rocks in Spain Salt - Mechanical Stalactites in South Dakota Dissolving (carbonation)Chemical Split rock in Scotland Frost Wedging - Mechanical Activity B: Weathering of different rocks Get the Gizmo ready: ● On the Simulation tab, click Reset ( ). ● Set the Average temperature to 25 °C and Precipitation to 250 cm/yr. Introduction: The Weathering Gizmo lets you explore weathering of four common rocks. Granite is a very hard rock formed from the crystallization of magma deep underground. Sandstone forms when sand grains become cemented together. Limestone is formed from ancient corals, shells and skeletons. Shale is formed from compacted mud. Question: How does weathering affect different rock types? 📷 1. Observe: Below Rock type, select Granite. Click Fastplay and run a simulation of about 100,000 years. Click the Tools palette and select Screen shot ( ). Right-click the image, click Copy, and then Paste the image below. Label this image “Granite.” 📷GRANITE igneous Describe what you see: There were several plants poking out of the rock, a few fissures, and much weathering. Look at Weathered rock above the outcrop. How much rock was weathered? 2,452 mB 2. Observe: Click Reset ( ). Repeat the same procedure for Sandstone, Limestone, and Shale. After 50,000 years, take an image of each, and describe your observations below. List the amount of weathered rock for each type of rock. 📷SANDSTONE sedimentary Describe what you see: multiple plants growing out of the rock weathering down Look at Weathered rock above the outcrop. How much rock was weathered? 8918 mB 📷LIMESTONE sedimentary Describe what you see: plants explode into rocks from pressure of Look at Weathered rock above the outcrop. How much rock was weathered? 12,165 mB weathered 📷SHALE sedimentary Describe what you see: a lot of worn rocks with numerous plants growing on them Look at Weathered rock above the outcrop. How much rock was weathered? 17,052 mB 3. Compare: Compare the results of weathering of different landscapes: A. Which rock types tend to weather into rounded shapes? sandstone shale B. Which rock weathers into caves and lumpy hills? granite limestone C. Which rock weathers most quickly? Most slowly? shale granite 4. Infer: Some types of weathering only affect certain kinds of rocks. The Types of weathering that apply to each kind of rock are listed above the outcrop. If a type of weathering does not affect the selected rock, it is faded. Select each rock and list the types of weathering that affect it. Granite: clay formation, frost wedging, other Sandstone: clay formation, frost wedging, other Limestone: dissolving, frost wedging, other Shale: clay formation, frost wedging, other *Note: Sandstones are only affected by clay formation when they contain minerals other than quartz. Sandstones that are pure quartz do not form any clay. Get the Gizmo ready: Activity C: Weathering rates ● On the Simulation tab, select Sandstone. ● Check that Frost wedging, Clay formation, and Other are all selected. Introduction: The most important things that determines how quickly a particular rock type weathers is the climate, or typical weather conditions. Rocks in cool and dry climates weather much differently than rocks in hot and rainy climates. Question: How does the climate and rock type affect how quickly a rock weathers? 1. Predict: In each “Climate type” box, Highlight weathering for the given weathering type. Weathering type Frost wedging the condition you think will lead to the fastest Hot Climate type Cold Wet Dry Clay formation Hot Cold Wet Dry Dissolving Hot Cold Wet Dry 2. Experiment: Click Return to original settings. Using the Gizmo, test the effect of precipitation on the rate of weathering by measuring the amount of weathered sandstone in 20,000 years with low and high precipitation. Be sure to keep all the other variables the same. Describe your results below. Weathered rock (low precip.) 172 m cubed Weathered rock (high precip.) 972 m cubed How does the amount of precipitation affect the amount of weathering? Rainfall hastens the occurrence of the weather. 3. Experiment: Click Reset and Return to original settings. Now test the effect of temperature on weathering rates. Describe your results below. Weathered rock (low temp.) 1,324 m cubed Weathered rock (high temp.) 1,560 m cubed How does the temperature affect the amount of weathering? It increases it by a little bit but not much. 4. Explain: Why do you think the rate of weathering tends to increase at hotter temperatures and higher amounts of rainfall? The rocks may crumble significantly more quickly in hotter environments and around liquid. 5. Experiment: Click Return to original settings and select Limestone. Turn off Frost wedging and Other so that only Dissolving is selected. Using the Gizmo, test the effect of precipitation and temperature on the rate of dissolving. Dissolved rock (low precip.) 0 m cubed Dissolved rock (high precip.) 2,792 m cubed Dissolved rock (low temp.) 2,677 m cubed Dissolved rock (high temp.) 1,490 m cubed Summarize your findings: High precipitation and cold temperatures both cause more rock to disintegrate. Dissolving occurs more quickly at low temperatures because cold water can dissolve more carbon dioxide than warm water. The greater the amount of dissolved carbon dioxide, the more acidic the water is and the faster the rate of dissolving. 6. Experiment: Click Return to original settings and select Shale. Test the effects of temperature on frost wedging and clay formation. Summarize your findings below. (Hint: Be sure to test just one type of weathering at a time.) Effect of temperature on frost wedging: Lower temperatures caused 3,266 m of rocks to weather while higher temperatures resulted in 0 Effect of temperature on clay formation: 201 meters of granite weathered in low temperatures and 2,710 meters in high temperatures as a result. ✏️Click on the chart below to summarizes different combinations of temperature and 7. Summarize: precipitation.