January 31, 2023
Group 6
Moises Menjivar - Manager
Katherine Nguyen - Recorder
Felice Peluso - Operator
Lab Design Section A Group 6: Intro to Materials Properties
1. Please list the materials and provide a description of the procedure you used for each
experiment.
Density
Description: According to the Archimedes Principle, a body submerged in a fluid
experiences a buoyant force (𝐹𝑏) equal to the weight of the displaced fluid (𝑊𝑓). It also
states that the 𝑊𝑓 is equal to the difference between the weight of a sample in air / dry
weight (𝑊𝑠) and the apparent weight of the sample when submerged in fluid / wet weight
(𝑊𝑤).
Procedure: A balance will be used to measure the dry (𝑚𝑠) and wet (𝑚𝑤) mass.
Remember that weight (𝑊) is simply mass (𝑚) times gravity (g). Using a scale, we first
measured the dry mass of our samples, which can be seen in the chart below. Afterwards,
Felice put a hook onto the scale, which he then placed a beaker of water on top of. A little
bucket is added onto the hook, and the scale is zeroed at this point. We then measured the
wet mass of our samples in this bucket.
Material
Mass in Air (g)
Mass in Water (g)
Steel
120.16
95.80
Aluminum
42.15
21.40
Copper
136.61
110.90
Brass
129.24
104.60
Acrylic
18.27
1.43
Nylon
18.07
1.25
PVC
14.28
-1.24
Sinker 1: Bi
53.29
44.60
Sinker 2: Sn
37.11
29.60
Sinker 3: CC
43.11
34.55
After measuring the masses, both dry and wet, calculate the density ratios, which will
give us the density of the material.
Material
Mass of Water (g)
(𝑊𝑠 − 𝑊𝑤)
Density of Material (g/ml)
𝑊
𝑠
( 𝑊 −𝑊
)
𝑠
𝑤
Steel
24.36
4.9327
Aluminum
20.75
2.0313
Copper
25.71
5.3135
Brass
24.64
5.2451
Acrylic
16.84
1.0849
Nylon
16.82
1.0743
PVC
15.52
.92010
Sinker 1: Bi
8.69
6.1323
Sinker 2: Sn
7.51
4.9414
Sinker 3: CC
8.56
5.0362
Mohs Hardness
Description: Mohs Hardness scale was a method created back in the 1800’s within the
mineralogy community. Using this scale, the community was able to measure the softest
materials, with metallic bonds or even weaker van der Waals bonds, and even the hardest
minerals with small atoms, packed tightly together with strong covalent bonds. The
hardness of these materials can be tested through scratching. The Mohs Hardness Scale,
starting with talc at 1 and ending with diamond at 10, is universally used around the
world as a way of distinguishing minerals and materials.
We were given 5 materials in this procedure, as shown below:
Procedure: We were provided a scratch kit with 4 picks of different hardness levels.
Felice used the picks to scratch the samples in order to determine their hardnesses, which
is then recorded below.
X - scratched
Hardness
4
5
6
7
8
9
Brass
X
X
X
X
X
X
Steel
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Aluminum
PMMA
Glass
2
3
X
2. Include a table of experimentally determined densities for the various materials you
studied along with standard values reported in textbooks, EduPack software or any
other reliable materials database which describe the "standard" densities for these
various materials.
You should discuss the precision with which you can make density measurements in
this laboratory and adhere to that precision in your reporting.
Material
Determined Density
(g/ml)
Standard Density
(g/ml)
Steel
4.9327
7.85
Aluminum
2.0313
2.7
Copper
5.3135
8.96
Brass
5.2451
8.5
Acrylic
1.0849
1.051
Nylon
1.0743
1.440
PVC
.92010
1.330
Sinker 1: Bi
6.1323
9.87
Sinker 2: Sn
4.9414
7.26
Sinker 3: CC
5.0362
3. Using the density property chart from CES EduPack, report the range of densities for
the following groups of materials:
Material Type
Density Range
(kg/m^3)
Metals and Alloys
4000+
Polymers
1000-3000
Ceramics (technical and non-technical)
2000-4000
Foams
0-1000
4. Calculate the weight percentage of Sn and Bi in the composite sinker
5. Include a table which ranks (in increasing order) the Mohs hardness of the various
materials tested in this lab and include the average hardness and uncertainty for each
material.
Material
Average Hardness
Aluminum
3
Brass
4
Steel
4
Uncertainty
PMMA
5
Glass
6
Through the procedures done on the five materials, the average hardness was lowest on
aluminum but highest on glass. Through our experiment, we did not experience any
uncertainty as after our first pick in each of the 5 materials, the following picks left
scratches as well. Therefore, uncertainty could no be calculated due to not experiencing
lower picks scratching compared to higher picks not scratching.
6. Please compare two of the materials you examined in the experiment in terms of how
the type of bonding and/or structure relates to their density or hardness.
Two materials used in today's lab were steel and glass. Steel was found to be one of the
denser materials, though it had a hardness of about 4. Glass, however, was the strongest
in terms of hardness from our samples. Steel has metallic bonding, which would explain
why it's less hard than glass, which is a polymer and has ionic bonds. Steel was one of the
denser materials since the elements that make up it's chemical structure are also
somewhat heavier than most other materials, meaning higher molecular mass and
therefore higher density.
Sources used:
Densities of Metals and Elements Table (engineersedge.com)
Density of Steel (amesweb.info)
What is the density nylon? - Reimagining Education
Bismuth - Density - Bi (periodic-table.org)