Lab 1 Finished
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Montgomery County Community College *
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120
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Geology
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Apr 3, 2024
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Name(s): Maddie Irwin and Liam Casey GLG 120ONLN-SPR24
Lab 1: Exploring Density, Minerals, and Rocks
Part I. Exploring Minerals and their properties, including density
Instructions: Complete the following as requested. Before you attempt to find the names of the minerals in question here, as well as their properties, I suggest you go over the video tutorial posted with this lab information (basically Prof Merle explaining how to identify the minerals here using the tools provided (mineral ID chart and youtube video link for each mineral. Always use the mineral ID chart attached with this lab, and along with any video and information provided, to answer the following items in this part of the lab. Hint: The following are the ONLY mineral names that are possible answers to the required exercises in this part of the lab: augite, calcite, plagioclase, hornblende, biotite and quartz
. Note: the names are not in order.
1a) To complete the table below, record the results of each of the properties as given in the following video: https://youtu.be/Mpuv0xojAZ0
. After you have recorded the results of each of the physical properties completed on the table, use the Mineral Physical Properties chart attached with this lab to find the name of the mineral shown on the youtube video (link given on this exercise). The name of the correct mineral name should match all physical properties recorded from video and should be one of the names highlighted in green on the instructions above:
Property/Name
Result/Finding
Color
Translucent, Dark
Luster
Non-metallic, vitreous Hardness
Hard (Glass hardness)
Cleavage cleavage direction 56 degrees or 124 degrees
Mass (grams)*
18.8g
Volume (cm3)*
5.9cm3
Streak
White to light grey streak
Mineral Name
Augite
*will be used in exercise 1b (below) to calculate density of the identified minerals
1
1b) What is the density of the mineral you identified in exercise 1a above? To figure out the answer to this question, let’s first learn some basics about density. Density is a useful concept, which will have a variety of applications in astronomy, meteorology, and geology as well as oceanography. Therefore, we will invoke and explore density several times in this course, as it explains so many phenomena related to Earth science. What is density? Density can be defined as the mass of an object or substance per unit volume
. What is meant by 'mass'? Mass is a term we use for the amount of matter a substance or material possess (by the way, matter is everything that has mass and occupies space. All matter is made of protons, electrons and neutrons). Volume is nothing more than the amount of space, which the object/substance occupies. This relationship can be expressed quantitatively as an equation:
DENSITY = MASS / VOLUME
(i.e., density equals
mass divided by
volume or D=m/v). Therefore, to obtain the density of a material, including the mineral you identified in exercise 1a, you will obtain the mass value and volume values given in the video and divide mass by volume. For example, let’s say that another mineral has a mass of 8.5grams and a volume of 13 cm3. D=m/v=8.5 g divided by 13cm3= 0.65 g/cm3. Therefore, the density of the mineral is 0.65 g/cm3. o
Use the video above to get the mass and volume of the mineral you identified in exercise 1a above and density equation given (also given above), to calculate the Density (D) of the mineral you identified in exercise 1a= 3.186 g/cm3.
o
Water has a density of 1g/cm3, while liquid mercury has a density of 13.2 g/cm3. There is a principle in science that states that materials that are denser than the medium they are in (like most rocks in water) will sink into the liquid, while materials that are less dense or lighter than the liquid, they are in will float (like leaves float on water). Use the principle, examples and the density of mineral 1a to answer the following questions
:
Will the mineral identified in 1a sink or float in water? Sink
Will the mineral identified in 1a sink or float in liquid mercury? Float
1c) More about density: Density of Fluids Fluids (liquids and gases) also have densities; their volumes and masses are a bit more difficult to obtain. In the next data table
you'll be given the mass and volume for a sample of tap water. The volume was measure in a graduated cylinder. Tap Water
Mass
4.28g
Volume
4.3ml
Density*
0.995
g/cm3
* include proper unit. They count towards your lab score. Establish a hypothesis: If you dissolve table salt (NaCl) in water, how would that alter the density of the water? The density of the salt 2
solution will be higher than the density of the pure water
.
Now calculate the density of a sample of salt water in the following data table.
Salt Water
Mass
7.85g
Volume
6.8ml
Density*
1.154g/cm3
* include proper unit. They count towards your lab score. Based on the salt-water calculation, would you accept or reject the hypothesis you stated above? Accept
Establish a theory for density: Density increases when mass: (choose one: increases OR decreases). Increases
Now, use the same process you did to complete exercise 1a above, to find out the name of each of the minerals shown on the following videos
(exercises 2-6, and 7 as extra credit): 3
2) You probably have seen this mineral, as is very common on the Earth’s crust because it’s very resistant to weathering. It is formed when some magma or lava hardens. It’s a silicate mineral and can come in several colors. https://www.youtube.com/watch?
v=JZAY0Cpa2Zk
. This mineral’s name is (Choose one of the following): augite, calcite, plagioclase, hornblende, biotite OR quartz
.
Property/Name
Result/Finding
Color
Translucent, dark to light gray
Luster
Non-metallic, glassy
Hardness
Hard , scratches glass
Cleavage None Mass (grams)*
64.5g
Volume (cm3)*
24.34cm3
Streak
white
Mineral Name
Hornblende 3) The mineral in the following video is also a silicate, belonging to the pyroxene group, commonly found in many igneous rock together with the mineral you just identified, as they both form at about the same temperatures and the same magma composition (mafic or intermediate; see Bowen’s reaction series on Chapter 3): https://www.youtube.com/watch?v=69Ig1FQw6i0
. This mineral’s name is (Choose one of the following): augite, calcite, plagioclase, hornblende, biotite OR quartz
.
Property/Name
Result/Finding
Color
dark green
Luster
Non metallic, vitreous Hardness
hard
Cleavage 86 and 94 degrees
Mass (grams)*
49.9g
Volume (cm3)*
15.1cm3
Streak
White to light grey
Mineral Name
Augite 4
4) The mineral described in the following video is a silicate belongs to the most common mineral group on the Earth’s crust (feldspars). The video states the cleavage is about 94 degrees but 90 is acceptable (
https://www.youtube.com/watch?v=W05X-
I2gAIw
). This mineral’s name is (Choose one of the following): augite, calcite, plagioclase, hornblende, biotite OR quartz
.
Property/Name
Result/Finding
Color
Translucent, white to light grey
Luster
Non metallic Hardness
Harder then glass and steal knife
Cleavage 86 and 94 degrees
Mass (grams)*
34.0g
Volume (cm3)*
12.6cm3
Streak
White streak
Mineral Name
Plagioclase
5) Clues to identify this mineral are that is dark-colored mica, softer than glass and even softer than the mineral Gypsum, it has one cleavage direction, so it breaks into thin flexible sheets. This mineral is common on metamorphic rocks like schist, but it can be found
in all rock types. https://www.youtube.com/watch?v=b0kXKsVBk70
. This mineral’s name is (Choose one of the following): augite, calcite, plagioclase, hornblende, biotite OR quartz
.
Property/Name
Result/Finding
Color
Translucent, dark green to black
Luster
Non metallic
Hardness
Softer than glass, harder than gypsum
Cleavage Yes, one cleavage plain
Mass (grams)*
66.3g
Volume (cm3)*
22.1cm3
Streak
Gray, green
Mineral Name
Biotite 5
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