Transcript Day 7
Day 7 Explain why this is true: When a metamorphic rock is forming, it may be subjected to extremely high temperatures, yet it never completely melts. Because if it melts, it would become molten rock. If it then cools and hardens, it would be an igneous rock. Daily Warm-Up Exercises 1 Labels Exercise 8.4 2 Naming Labels 3 Naming Labels and Explanatory Labels 4 Captions Exercise 8.5 5 CaSE Book Student Rescource Book, Page 23 6 Without a caption, it is difficult to know much about this image: 7 With the caption in place, the viewer has the necessary information. As magma cools, different minerals come together to form crystals, as in this granite. The crystals grow together, filling the spaces. 8 Salol Crystals (Part 2, steps 1-10) Investigation 8 One Rock to Another 9 Intrusive & Extrusive Rocks Examine your igneous rocks with a hand lens. Look for crystals (pieces of pure minerals) in the rocks. 10 Intrusive & Extrusive Rocks Is there a relationship between crystal size and whether the igneous rock was intrusive or extrusive? Intrusive rocks like granite have larger crystals. Obsidian doesn’t appear to have any crystals. Why do some igneous rocks have larger crystals than others? 11 Salol Rocks must reach 750 0C (1382 0F) or more before they will begin to melt. We can’t melt rocks in class, but we will use Salol to simulate the melting and cooling of a rock. Salol melts at the temperature of hot tap water. 12 Observe Salol Melting Open to a new page in your journal. Title your page: Salol Observations 13 Materials for Salol Lab Each group needs: journal to record observations two bottles of Salol hot and cold water THE BOTTLES MUST STAY CLOSED 14 Discuss What Happened What did the salol look like before you placed it in hot water? white crystals on the side of the bottle How long did it take for the salol to melt? about 1 minute 15 Discuss What Happened What happened when you placed the salol in the cold water? it hardened and turned back into crystals What do the crystals look like? some look like crushed ice or big sugar crystals; others look like flat needles or feathery branches; some grow in rosettes from a central point or circle 16 Crystallization Forming crystals is called crystallization. Crystal shape is one of the properties geologists use to help them identify minerals. Salol crystals form the same shapes each time they crystallize (needles; feathers; diamonds; broken ice). 17 Melting Temperature How can we find out the temperature at which salol melts? put the bottle in different temperatures of water and find the lowest temperature at which it will melt Salol melts at around 40 0C. If the temperature drops below 40 0C, the salol will begin to crystallize. 18 Crystal Size Investigation Design an experiment using salol to answer the following questions: • Why do some igneous rocks have larger crystals than others? • What are some variables that might affect the size of the crystals that form? 19