GEOG15001 Lab report 1 Catherine Gailey

GEOG15001.002 Lab Week 1: Density Catherine Gailey Guiding Question: How does crustal density influence the basic topography of Earth? Introduction: The Earth is covered in shifting huge layers called plates. These plates are what create canyons, mountains, volcanoes, and earthquakes in/on the Earths surface. This is because the plates are constantly shifting. Plates usually shift in three different ways, or boundaries. The first is a divergent plate boundary, this is when the plates are moving away from each other, creating canyons or trenches in the Earth’s surface. Second is a convergent plate boundary, when plates are moving towards each other creating mountains or volcanoes. Lastly is a transform plate boundary, when the plates are parallel to each other but moving in opposite directions. When a continental plate meets with an ocean crust, the oceanic crust gets subducted, or pulled into the Earth’s mantle. This is because the Oceanic crust is denser but thinner than the continental crust. Consequently, crustal density influences the basic topography of the Earth by creating volcanoes, mountains, great canyons, earthquakes and more. This is because the densities and thickness are either the same or different. This was found through a measurement of their masses and volume to find their density. Methods: Our method for finding the density of our “crusts” was by measuring in grams rocks that represented each crust; Continental (Granite), Oceanic (Basalt), and Mantle (Peridotite). After we measured their weight in grams three times to ensure an average weight, we measured the volume of our rocks by seeing the displacement of water from a beaker in milliliters and converted it to cm^3. We recorded the change in water three separate times. From getting these two measurements (grams and cm^3), we could then find the density. We found the density by dividing grams by cm^3. After the hands-on part of the lab. We used our measurements to find the crustal root and how high the block floats above the water. To find the crustal root, you must divide the density of each crust; Continental and oceanic; by the density of periodotite; or the mantle; after we multiplied it by the given crustal thickness of each. The measurements will be listed below. Results: Weight (grams) Average Granite 193.72 193.72 193.72 193.72 Basalt 452.54 452.55 452.56 452.55 Peridotite 351.24 351.25 351.24 351.243333 Volume (cm^3) Average Granite 75 75 75 75 Basalt 150 150 150 150 Peridotite 115 115 115 115 Density (grams/cm^3) Average Granite 2.58 2.58 2.58 2.58 Basalt 3.03 3.01 3.01 3.01666667 Peridotite 3.05 3.05 3.05 3.05