One of our assignments for Spring 2021 was a lab report. In this assignment, I created a lab report on a fictional, but highly realistic lab regarding the densities of samples of water taken from New York Cities waterways.

The density of New York City’s diverse waterways.

Domenico Gioffre

The City College of New York

ENGL 21007: Writing for Engineers

Professor Danielle Carr

March 23, 2021

Table of Contents

Abstract———————————————————————————————-3

Introduction—————————————————————————————-3

Hypothesis——————————————————————————————4

Materials———————————————————————————————4

Procedure——————————————————————————————-4

Results and Data———————————————————————————5

Discussion——————————————————————————————6

Conclusion——————————————————————————————6

Acknowledgements——————————————————————————7

References——————————————————————————————7

Abstract:

The density of water has a large effect on marine life and the people who inhabit the areas around that water. Therefore it is imperative that the densities of the water around New York City is known.

To do this, our team collected samples from different locations on the New York City waterfront, then used a scientific formula (Density = Mass/Volume) to calculate the density of the water in that particular area.

The team hypothesized that because the water entering from the ocean has a density of 1.025 kg/ml, and the freshwater that comes from runoff has a density of 1.000kg/ml (all pure water has a density of 1, this is general knowledge), then the water around NYC has a density in between those two.

The results showed that the hypothesis is true. Furthermore, the farther south the sample is taken, the higher the density. We can only speculate that this is a result of being closer to the ocean, which is a source of denser saltwater.

Introduction:

NYC is a water city. Manhattan is an island, surrounded by large bodies of water. The water around Manhattan has many different influencers on its composition. As this water has much land around it, it receives much runoff (NRDC.org), and it is also connected to the Atlantic Ocean.

Density is a measure of how much mass an object contains for a given volume of that object. For example, a balloon may be very very large, yet have little mass. We can say that a balloon has low density. On the other hand, a lead fishing weight is very tiny, yet surprisingly heavy. We would say that this object is very dense. You may know someone who is very muscular. This person may be surprisingly heavy compared to people of similar size, as muscle is known to be very dense. In terms of liquids, some liquids are more dense than others.

This leads to an interesting question: what is the density of the water surrounding NYC?

The freshwater coming in from the land has a density of 1 kg/l, and the density of the pure saltwater coming in from the ocean has a density of 1.0025 kg/l (RIC.edu). Therefore, we believe the density of the water around Manhattan is in between those two densities.

To test this, we will test the densities of samples of water obtained from locations around Manhattan. To do this, we will need special permission and access from the NYPD, and NYSDOT, which we gratefully received.

Hypothesis: Saltwater, as opposed to freshwater, has a greater density as the salt increases the mass of the water without significantly changing its volume. The water in NYC is a mixture of the less dense freshwater, and the denser saltwater. Therefore NYC’s water will have a density between that of pure freshwater (1.00 kg/ml) and that of pure saltwater (1.025 kg/ml)

Materials:

• two beakers
• Scientific Scale
• Sharpie pen
• Calculator
• 4, gallon containers (1 spare)
• Funnel
• Paper towels (for spills)
• Paper/computer for data
• State/Federal ID
  • To work with NYPD and NYSDOT

Procedure:

1. With access granted by the Department of Transportation, and the NYPD:
   1. Collect 1 gallon of water from underneath the Brooklyn Bridge
   2. Collect 1 gallon of water from above the Holland Tunnels position
   3. Collect 1 gallon of water from the shore of the southernmost tip of Manhattan
2. Determine the density of each sample by following this procedure for each, then record data
   1. Weigh a 100ml beaker
      1. Record this weight
   2. Fill this beaker with 100ml (this is your volume for your density calculations below) of water from a specific sample
      1. Use a funnel
   3. Now weight the beaker with the water
   4. To get the mass of the water, subtract the mass of the beaker
   5. Enter the mass of the water into the formula below to get the density of the sample water
      1. D=m/v
3. Observe and analyze the data
   1. Is the water denser than freshwater? Is it less dense than saltwater?

Results and data:

Here is a map of the locations of all the points where samples were taken. The points are marked with red hexagons. Next to the hexagon is the samples location number. These samples are choosen by their poximity to the ocean. The intent was to choose samples of varying distance from a saltwater source.

The specific locations of samples are listed in the table below the map.

LOCATION DENSITY

Location 1 (Brooklyn Bridge): 1.020 kg/ml

Location 2 (Holland Tunnel): 1.015 kg/ml

Location 3 (Lower Manhattan): 1.023 kg/ml

Location 4 (Lincoln Tunnel): 1.010 kg/ml

Location 5 (Williamsburg Bridge): 1.017 kg/ml

This data proves our hypothesis true, as the densities of the samples are all less than 1.025kg/ml (pure saltwater), and greater than 1.00kg/ml (pure freshwater).

Discussion:

• Why is this topic important?

• Differences in water densities help create currents. Currents have an impact on the weather. Knowing the different densities can help map out currents, which can be used to determine the water’s impact on local weather in NYC.
• NYC marine biologists will benefit from an extensive mapping of the local waters densities, which can help them achieve their goal of preservation of local fish stocks.

• What else is there to learn about the subject?

• Further work can be done to sample water in different areas of the city’s water masses in order to have a more complete map of the water densities throughout New York City.
• Measure the effect the different densities have on the height of a boat in water around different locations. The density might have a tiny effect on how deep a small boat sits in the water, but a large effect on a large container ship. This can make a ship sit higher than planned, causing it to strike a bridge, or cause a ship to sit deeper, leading to a hull strike.

Conclusion:

As a result of the Lab report, the experiment conducted shows the differences between the densities of water around New York City. In this Lab, we gathered 30mL of Saltwater from around the Brooklyn Bridge, Lincoln Tunnel, Holland Tunnel, Williamsburg Bridge, and Lower Manhattan shore in order to weigh their masses and determine their densities. We hypothesised that their densities would reflect a combination of both Saltwater and Freshwater.

Upon completion of our lab report, we learned that the brackish water (water that is a combination of saltwater and freshwater) has a density in between that of freshwater and saltwater. This proves our hypothesis right.

Additionally, further research must be done on the salinity of the water around Manhattan. Our team hypothesizes that the water further south has a higher salt content, as the water gets denser the farther south we take samples. This would make sense as the southern waters are closer to the open ocean.

References:

Chaisson, C. (2019, March 13). When it rains, it POURS raw sewage into New York City’s Waterways. Retrieved March 25, 2021, from https://www.nrdc.org/stories/when-it-rains-it-pours-raw-sewage-new-york-citys-waterways

Duxbury, A. C. (n.d.). Density of seawater and pressure. Retrieved March 25, 2021, from https://www.britannica.com/science/seawater/Density-of-seawater-and-pressure

Geyer, W. (2019, September 16). Brackish water: Where fresh WATER rivers meet a salt water sea. Retrieved March 25, 2021, from https://www.whoi.edu/oceanus/feature/where-the-rivers-meet-the-sea/

OC202 topic 1: Seawater PROPERTIES. (n.d.). Retrieved March 25, 2021, from http://www.ric.edu/faculty/PSCI103/Seawater/Seawater_notes.htm

Stormwater management. (n.d.). Retrieved March 25, 2021, from https://www1.nyc.gov/site/dep/water/stormwater-management.page

The oceans. (n.d.). Retrieved March 29, 2021, from https://www.open.edu/openlearn/science-maths-technology/the-oceans/content-section-3.2

ACKNOWLEDGEMENTS

We would like to thank the NYPD Special Operations Division, and the NYSDOT Citizen Affairs Division for their access and permission to sample water from watercraft and access protected areas. WIthout them, this research would not be possible.

AUDIENCE PROFILE SHEET

Reader’s Name: Mariners, Biologists (Marine), swimmers, state and city water agencies

Reader’s Job Title: Various, written above

Education: None required, familiarity with water phenomena is key (for example, sailors are sometimes lacking formal education, yet are highly knowledgeable on water phenomena

Professional Experience: Various, written above

Job Responsibilities: Various,

Personal Characteristics: Familiarity with water

Cultural Characteristics:

Attitude Toward the Writer: Curiosity, need to know

Attitude Toward the Subject: Curiosity, need to know

Expectations About the Subject: Preconceptions based on prior experience (for example: sailing through the Hudson River)

Expectations About the Document: A formal, professional lab report

Reasons for Reading the Document: Need to know the density of local water, curiosity….

Ways of Reading the Document: Skimming, skipping, or slow. Depends on what you need.

Skim it _Yes__ Study It Yes___ Read a portion of it _No__ Which portion?

Modify it and submit it to another reader _NO__

Attempt to implement recommendations _YES__

Use it to perform a task or carry out a procedure _NO__

Use it to create another document _YES__

Other ___ Explain

Reading Skills: Mediocre.

Reader’s Physical Environment: Anywhere, even on the bridge of a ship sailing into the harbor.

Self Reflection:

The genre of this assignment is a lab report because it follows the structure and composition of a lab report. This includes an abstract, introduction, materials, procedure, results, discussion, conclusion, and sources for the information. I have chosen a digital medium to share the results of my research as this is the modern way of publishing lab reports. The scientific world is a international one, and a paper medium would be insufficient to meet the fast demands of the modern scientific world.

The purpose of my lab report is to inform my audience; scientist’s, marine biologist’s, mariners, and recreational water athletes of the relatives densities in the different parts of the water around Manhattan. These densities can have a huge impact on navigating the waterways, and the studies of marine life that is local to the area.

My targeted audience is marine biologists, local merchant marine regulators (Coast Guard…), recreational swimmers, local and state government agencies (city and state), and other scientists. Besides recreational swimmers, my audience would be of higher understanding of marine science. Merchant Mariners and other sailors may not necessarily have a high education, but their understanding of the marine phenomena is more than sufficient for this lab.

My exigence for my lab report is the lack of appreciation and understanding of our local waterways. I believe most New Yorkers only see our waterways as a pretty sight and inconvenience for traveling between boroughs. I also wanted to prove that science experiments and labs do not require expensive equipment and intense calculations. These misconceptions of science experiments tend to turn people away from experimenting to answer their questions.

With this assignment I have met multiple course learning outcomes. I was able to “develop and engage in the collaborative and social aspects of writing processes” by working as a group to come up with a suitable lab topic: one that was not too difficult, but complex enough to warrant a college level lab report. I also primarily used peer review to create my final product.

The changes I made are mostly inspired by the comments of the peers in my group. I was also able to “formulate and articulate my stance through my writing”, and although I may not have had an actual stance (besides my hypothesis, although despite having a hypothesis my experiment must still remain neutral), I had to convey the importance of the topic of my lab.