Types of Rocks Webquest!

Rock your science class! Explore types of rocks with an interactive webquest.

Rock Cycle Interactive CLICK HERE TO ACCESS THE WEBQUEST! Once you open the website, click the red link that says, "Begin with Types of Rocks" Use the drop down boxes to fill in the blanks. Rocks are not all the same! The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock. Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You can often see sand, pebbles, or stones in the rock, and it is usually the only type that contains fossils. Examples of this rock type include conglomerate and limestone.Metamorphic rocks are formed under the surface of the earth from the metamorphosis (change) that occurs due to intense heat and pressure (squeezing). The rocks that result from these processes often have ribbonlike layers and may have shiny crystals, formed by minerals growing slowly over time, on their surface. Examples of this rock type include gneiss and marble.Igneous rocks are formed when magma (molten rock deep within the earth) cools and hardens. Sometimes the magma cools inside the earth, and other times it erupts onto the surface from volcanoes (in this case, it is called lava). When lava cools very quickly, no crystals form and the rock looks shiny and glasslike. Sometimes gas bubbles are trapped in the rock during the cooling process, leaving tiny holes and spaces in the rock. Examples of this rock type include basalt and obsidian. Match the key characteristic that helps identify the rock with the definition. Crystals Small, flat surfaces that are shiny or sparkly, like tiny mirrors. Fossils Imprints of leaves, shells, insects, or other items in the rock. Gas Bubbles "Holes," like Swiss cheese, in the rock. Glassy Surface A shiny and smooth surface, like colored glass. Ribbonlike Layers Straight or wavy stripes of different colors in the rock. Sand or Pebbles Individual stones, pebbles, or sand grains visible in the rock. Click the red link that says, "Next: Start your rock collection"Click "Begin" Match the rock to correct description. Gneiss This rock has ribbonlike layers. It forms from heat and pressure. Marble This rock has crystals. It forms from heat and pressure. Basalt This rock forms from lava cooling and makes up most of the ocean floor. Obsidian This rock has a glassy surface and cools too quickly to form crystals. Limestone You can see fossils in this rock. It forms when seashells and skeletons of marine animals were compressed on the seafloor Conglomerate Sand and pebbles are visible in this rock. Click the red link, "Identify Rock Types" and click "Begin" to identify the rocks.Click the red link, "How Rocks Change" Use the reading to fill in the blanks. Does it seem to you that rocks never change?For example, if you find a chunk of granite today, can you expect that it will still be granite at the end of your lifetime? That may well be true — but only because our lifetimes are very short relative to the history of the earth.If we take a step back to look at geologic time (which focuses on changes taking place over millions of years), we find that rocks actually do change! All rocks, in fact, change slowly from one type to another, again and again. The changes form a cycle, called "the rock cycle." The way rocks change depends on various processes that are always taking place on and under the earth's surface. Now let's take a closer look at each of these processes. Heat and Pressure What happens to cookie dough when you put it in the oven? The heat of the oven produces changes in the ingredients that make them interact and combine. Without melting the dough, the heat changes it into a whole new product — a cookie. A similar process happens to rocks beneath the earth's surface.Due to movements in the crust, rocks are frequently pulled under the surface of the earth, where temperatures increase dramatically the farther they descend. Between 100 and 200 kilometers (62 and 124 miles) below the earth's surface, temperatures are hot enough to melt most rocks. However, before the melting point is reached, a rock can undergo fundamental changes while in a solid state — morphing from one type to another without melting.An additional factor that can transform rocks is the pressure caused by tons of other rocks pressing down on it from above; heat and pressure usually work together to alter the rocks under the earth's surface. This kind of change, which results from both rising temperature and pressure, is called metamorphism, and the resulting rock is a metamorphic rock. Click the red link "Next" Use the reading to fill in the blanks. MeltingWhat happens to a chocolate bar when it gets very hot? It melts. The same thing happens to a rock when it is heated enough. Of course, it takes a lot of heat to melt a rock. The high temperatures required are generally found only deep within the earth. The rock is pulled down by movements in the earth's crust and gets hotter and hotter as it goes deeper. It takes temperatures between 600 and 1,300 degrees Celsius (1,100 and 2,400 degrees Fahrenheit) to melt a rock, turning it into a substance called magma (molten rock).CoolingWhat would you do to turn a melted chocolate bar back into a solid? You'd cool it by putting it into the refrigerator until it hardens. Similarly, liquid magma also turns into a solid — a rock — when it is cooled. Any rock that forms from the cooling of magma is an igneous rock. Magma that cools quickly forms one kind of igneous rock, and magma that cools slowly forms another kind. When magma rises from deep within the earth and explodes out of a volcano, it is called lava, and it cools quickly on the surface. Rock formed in this way is called extrusive igneous rock. It is extruded, or pushed, out of the earth's interior and cools outside of or very near the earth's surface. What if the magma doesn't erupt out of a volcano, but instead gets pushed slowly upward toward the earth's surface over hundreds, thousands, or even millions of years? This magma will also cool, but at a much slower rate than lava erupting from a volcano. The kind of rock formed in this way is called intrusive igneous rock. It intrudes, or pushes, into the earth's interior and cools beneath the surface. Click the red link, "Next" Use the reading to fill in the blanks. Weathering ErosionWhat do dandelions rely on to separate their seeds, carry them, and deposit them elsewhere? The wind. All objects on the earth's surface are exposed to the wind, along with many other elements — water, the sun, temperature changes. Over time, these factors wear objects down and break them apart. The resulting bits and pieces of material are called sediment. Sediment is then transported by wind and water, often ending up far from where it started. These processes of breakdown and transport due to exposure to the environment are called weathering and erosion. Weathering and erosion affect all rocks on the earth's surface. Compacting CementingWhat happens to a loose pile of garbage when it's put into a compactor? The squeezing of the machine produces a solid cube of compacted garbage. The same thing happens to sediment formed from the weathering and erosion of rock. Over time, sediment accumulates in oceans, lakes, and valleys, eventually building up in layers and weighing down the material underneath. This weight presses the sediment particles together, compacting them. Water passing through the spaces in between the particles helps to cement them together even more. This process of compacting and cementing sediment forms sedimentary rock. Click the red link, "Transform the Rock"Click "Begin" Weathering and erosion Melting Cooling Heat and Pressure Compacting and Cementing Weathering and erosion Melting Cooling Heat and Pressure Compacting and Cementing Weathering and erosion Melting Cooling Heat and Pressure Compacting and Cementing Weathering and erosion Melting Cooling Heat and Pressure Compacting and Cementing Weathering and erosion Melting Cooling Heat and Pressure Compacting and Cementing Click the red link, "The Rock Cycle Diagram"Look over the rock cycle diagram.Click "Done" and then "Begin" Label the Rock Cycle Diagram Use the following terms to label the rock cycle diagram:metamorphic rocksedimentary rockigneous rocksedimentmagmameltingcoolingweathering and erosioncompacting and cementingheat and pressure **You can use words twice**Everything should be lowercase magma melting melting cooling weathering and erosion weathering and erosion sediment compacting and cementing sedimentary rock heat and pressure metamorphic rock igneous rock heat and pressure weathering and erosion Click the red link, "Test Your Skills"Click the red button, "Next"Take the quiz. Did you take the quiz? CLICK YES AND GET 5 FREE POINTS!**IF YOU DON'T CLICK YES, YOU WILL LOSE 5 POINTS!!!! Yes What score did you get on the quiz? Please be honest - you will not lose any points if you did not do well on this 'quiz'