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devry sci214 week 4 lab




Question;Name____________________________________________________Section________________Date;Week 4: Exploring Earth ? Igneous Rocks and;Coordinate Systems;Invitation;to Inquiry;Survey the use of rocks used in building;construction in your community. Compare the type of rocks that are used for;building interiors and those that are used for building exteriors. Are any;trends apparent for buildings constructed in the past and those built in more;recent times? If so, are there reasons (cost, shipping, other limitations);underlying a trend or is it simply a matter of style?;Part;1: Rocks on Earth;Background;Igneous rocksare rocks;that form from the cooling of a hot, molten mass of rock material.Igneous;rocks, as other rocks, are made up of various combinations of minerals. Each;mineral has its own temperature range at which it begins to crystallize;forming a solid material. Minerals that are rich in iron and magnesium tend to;crystallize at high temperatures. Minerals that are rich in silicon and poor in;iron and magnesium tend to crystallize at lower temperatures. Thus, minerals;rich in iron and magnesium crystallize first in a deep molten mass of rock;material, sinking to the bottom. The minerals that crystallize later will;become progressively richer in silicon as more and more iron and magnesium are;removed from the melt.;Igneous;rocks that are rich in silicon and poor in iron and magnesium are comparatively;light in density and color. The most common igneous rock of this type is granite;which makes up most of the earth?s continents. Igneous rocks that are rich in;iron and magnesium are dark in color and have a relatively high density. The;most common example of these dark-colored, more dense rocks is basalt;which makes up the ocean basins and much of the earth?s interior. Basalt is;also found on theearth?s surface as a result of volcanic activity. Other common igneous rocks are obsidian;pumice and gabbro that you will investigate through the lab.;Procedure;1. For;this experiment you can chose to either measure 5 different rocks (options;given by your instructor ? likely basalt, granite, obsidian, pumice and gabbro);or 5 different specimen of the same rock.;Decide with your lab partners which you?d like to do.;2. Use;a balance to find the mass of your first rock. Record the mass in Data Table 4.1.;Tie a 20-cm length of nylon string around the rock so you can lift it with the;string. Test your tying abilities to make sure you can lift the rock by lifting;the string without the rock falling.;3. Place;an overflow can on a ring stand, adjusted so the overflow spout is directly;over a graduated cylinder.;4. Hold;a finger over the overflow spout, then fill the can with water. Remove your;finger from the spout, allowing the excess water to flow into the cylinder.;Dump this water from the cylinder, then place it back under the overflow spout.;5. Grasp;the free end of the string tied around the first rock, then lower the rock;completely beneath the water surface in the overflow can. The volume of water;that flows into the graduated cylinder is the volume of the rock. Remembering;that a volume of 1.0 mL is equivalent to a volume of 1.0 cm3;record the volume of the rock in cm3;in Data Table 4.1.;6. Calculate the;mass density of this first rock and record the value in the data table.;7. Repeat;procedure steps 1 through 5 with 4 more rocks.;Results;1. In what ways;do igneous rocks have different properties?;2.;Explain the theoretical process;or processes responsible for producing the different properties of igneous rock;3.;According to the experimental;evidence of this investigation, propose an explanation for the observation that;the bulk of the earth?s continents are granite, and that basalt is mostly found;in the earth?s interior.;4.;Was the purpose of this lab;accomplished? Why or why not? (Your answer to this question should show;thoughtful analysis and careful, thorough thinking.);Part 2;Coordinate systems on Earth;Background;The continuous rotation and revolution of the;earth establish an objective way to determine directions and locations on the;earth. If the earth were an unmoving sphere there would be no side, end, or;point to provide a referent for directions and locations. The earth?s rotation;however, defines an axis of rotation which serves as a reference point for;determination of directions and locations on the entire surface. The reference;point for a sphere is not as simple as on a flat, two-dimensional surface, because;a sphere does not have a top or side edge. The earth?s axis provides the;north-south reference point. The equator is a big circle around the earth that;is exactly halfway between the two ends, or poles of the rotational axis. An;infinite number of circles are imagined to run around the earth parallel to the;equator. The east- and west-running parallel circles are called parallels.;Each parallel is the same distance between the equator and one of the poles all;the way around the earth. The distance from the equator to a point on a;parallel is called the latitude of that point. Latitude tells you how;far north or south a point is from the equator by telling you on which parallel;the point is located.;Since a parallel is a;circle, a location of 40? N latitude could be anyplace on that circle around;the earth. To identify a location you need another line, one that runs pole to;pole and perpendicular to the parallels. North-south running arcs that;intersect at both poles are called meridians. There is no naturally;occurring, identifiable meridian that can be used as a point of reference such;as the equator serves for parallels, so one is identified as the referent by;international agreement. The reference meridian is the one that passes through;the Greenwich Observatory near London, England, and is called the prime;meridian. The distance from the prime meridian east or west is called the longitude.;The degrees of longitude of a point on a parallel are measured to the east or;to the westfrom the prime meridian up to 180?.;Locations;identified with degrees of latitude north or south of the equator and degrees;of longitude east or west of the prime meridian are more precisely identified;by dividing each degree of latitude into subdivisions of 60 minutes (60?) per;degree, and each minute into 60 seconds (60?). In this investigation you will;do a hands-on activity that will help you understand how latitude and longitude;are used to locate places on the earth?s surface.;Procedure;1. Obtain;a lump of clay about the size of your fist. Knead the clay until it is soft and;pliable, then form it into a smooth ball for a model of the Earth.;Obtain;a sharpened pencil. Hold the clay ball in one hand and use a twisting;motion to force the pencil all the way through the ball of clay. Reform;the clay into a smooth ball as necessary. This pencil represents the;earth?s axis, an imaginary line about which the earth rotates. Hold the;clay ball so the eraser end of the pencil is at the top. The eraser end of;the pencil represents the North Pole and the sharpened end represents the;South Pole. With the North Pole at the top, the earth turns so the part;facing you moves from left to right. Hold the clay ball with the pencil;end at the top and turn the ball like this to visualize the turning Earth.;The;Earth?s axis provides a north-south reference point. The equator is a;circle around the Earth that is exactly halfway between the two poles. Use;the end of a toothpick to make a line in the clay representing the;equator.;Hold the clay in one hand;with the pencil between two fingers. Carefully remove the pencil from the;clay with a back and forth twisting motion. Reform the clay into a smooth;ball if necessary, being careful not to destroy the equator line. Use a;knife to slowly and carefully cut halfway through the equator. Make a;second cut down through the North Pole to cut away one-fourth of the ball;as shown in Figure 4.1. Set the cut-away section aside for now.;Equator;Figure 4.1;5. Place;a protractor on the clay ball where the section was removed. As shown in Figure;4.2, the 0? of the protractor should be on the equator and the 90? line should;be on the axis (the center of where the pencil was). You may have to force the;protractor slightly into the clay so the 0? line is on the equator. Directly;behind the protractor, stick toothpicks into the surface of the clay ball at;20?, 40?, and 60? above the equator on both sides. Remove the protractor from;the clay and return the cut-away section to make a whole ball again.;6.;Use the end of a toothpick to;make parallels at 20?, 40?, and 60? north of the equator, then remove the six;toothpicks. Recall that parallels are east and west running circles that are;the same distance from the equator all the way around the earth (thus the name;parallels). The distance from the equator to a point on a parallel is called;the latitude of that point. Latitude tells you how far north or south a;point is from the equator. There can be 90 parallels between the equator and;the North Pole, so a latitude can range from 0? North (on the equator) up to;90? North (at the North Pole).;90?;60?;40?;60?;20?;40?;0?;20?;Figure 4.2;4. Since;a parallel is a circle that runs all the way around the earth, a second line is;needed to identify a specific location. This second line runs from pole to pole;and is called a meridian. To see how meridians identify specific locations;again remove the cut section from the ball of clay. This time place the;protractor flat on the equator as shown in Figure 4.3, with the 90? line;perpendicular to the axis. Stick toothpicks directly below the protractor at;0?, 60?, 120?, and 180?, then remove the protractor and return the cut-away;section to make a whole ball again. Use a toothpick to draw lines in the clay;that run from one pole, through the toothpicks, then through the other pole. By;agreement, the 0? line runs through Greenwich near London, England and this;meridian is called the prime meridian. The distance east or west of the prime;meridian is called longitude. If you move right from the prime meridian;you are moving east from 0? all the way to 180? East. If you move left from the;prime meridian you are moving west from 0? all the way to 180? West.;3. Use;a map or a globe to locate some city that is on or near a whole number latitude;and longitude. New Orleans, Louisiana, for example, has a latitude of about 30?;N of the equator. It has a longitude of about 90? W of the prime meridian. The;location of New Orleans on the earth is therefore described as 30? N, 90? W.;Locate this position on your clay model of the earth and insert a toothpick.;Compare your model to those of your classmates.;180?;Prime;Meridian;120?;90?;30?;60?;Figure 4.3;Results;1. What;information does the latitude of a location tell you?;2. What;information does the longitude of a location tell you?;3. According;to a map or a globe, what is the approximate latitude and longitude of the;place where you live?;4. Explain how;minutes and seconds are used to identify a location more precisely.;5.;Was the purpose of this lab;accomplished? Why or why not? (Your answer to this question should show;thoughtful analysis and careful, thorough thinking.);Data;Table 4.1 Density of Igneous;Rocks;Type;of Rock;Mass;(g);Volume;(cm^3);Density;(g/cm^3);Rock 1;Rock 2;Rock 3;Rock 4;Rock 5


Paper#62850 | Written in 18-Jul-2015

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