Lab Report

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Salinity and its Effects on Density:

Abstract 

The purpose of this lab is to experiment and identify the relationships between the densities of different water around Manhattan This lab involves the tasks of distinguishing the solutions in three different beakers all of which have the same volume of 100 Milliliters. Density equals the Mass of the weighted water in the Beakers divided by the 1000mLs of the solution. Illustrated in this lab is a detailed overview of the effects that salinity has on the Density, in Grams/cm^3. Our goal is to uncover the Densities of the 3 locations around Manhattan that way we can determine the areas of New York City that have the most densified bodies of water. Since the volume will be the same, water around NYC will be denser than Freshwater but less dense than Saltwater. 

Introduction

Manhattan is an island surrounded by large bodies of water. The water all around Manhattan is filled with a multitude of substances and solutes. This leads to the question: What is the density of water surrounding New York City? Freshwater has a density of exactly 1kg/L and the density of saltwater coming out of the ocean has a density of 1.0025kg/L. (RIC.edu) Saltwater has a slightly greater density than Freshwater because of the minimal increase in mass of the water without a change in volume. Because the water around Manhattan is a mixture of less dense freshwater and denser saltwater, we believe that the densities for the areas around Manhattan will be in between their densities of 1. 000kg.L and 1.0025kg/L respectively. 

Materials

  • Lab Weights (4, 5mg Weights) 
  • 3 Beakers 
  • Scientific Scale 
  • Sharpie Pen 
  • Calculator 
  • 4, gallon containers (1 spare) 
  • Funnel 
  • Paper Towels (For Spills)
  • Paper or Computer to document the data  

Procedure

  1. Collection of Manhattan Water 
  2. Collect 1 Gallon of water from underneath the Brooklyn Bridge 
  3. Collect 1 Gallon of water from above the Holland Tunnel 
  4. Collect 1 Gallon of water from the shore of the southernmost tip of Manhattan 
  5. Determining the Density of the Samples 
  6. Weight an empty 100mL beaker 
  7. Fill these beakers with 100mL of water from each specific sample (Volume) 
  8. Now weigh these beakers with the water 
  9. To get the mass of the water, subtract the mass of the beaker empty 
  10. Enter the mass of the water into the density formula (D=m/v) to get the density of the sample water 
  11. Observe and analyze the data 

Lab Results

            Brooklyn Bridge Density: 1.015kg/L

            Holland Tunnel Density:  1.020kg/L

            Lower Manhattan Density: 1.023kg/L

Discussion

            This topic is important because knowing where the differences in densities are in different areas of NYC like the Hudson river, indicates where higher concentrations of saltwater are present. Knowing what we know from this Lab, we could share some of this information with local marine biologists who have interest in learning more about how different densities effect the local marine ecosystem. 

Conclusion

As a result of the Lab report, the experiment conducted shows the similarities between the density of saltwater, freshwater, and public New York City water. In this Lab, we gathered 30mL of Saltwater from underneath the Brooklyn Bridge, Holland Tunnel, and Lower Manhattan shore in order to weigh their masses and determine their densities. We hypothesized 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

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 

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 

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

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 

Reflection

The genre of this assignment is a lab report because I have structured this paper to include all of the main components of a Lab Report. In this Lab Report includes an abstract, introduction, materials, procedure, results, discussion, conclusion and reference page for all outside sources I used. The purpose of this lab report is to inform scientist and marine biologists of the water densities of different bodies of water around Manhattan, for the density of water is extremely important to the world of marine life. I developed this lab report with the goal of reaching both local marine biologists because they study the ecosystem in the ocean and knowing the density of different bodies of water around New York City will help with their research. I feel on a daily basis, New Yorkers don’t necessarily respect the environment they’re in and the water in the city often pays the biggest price for it. With this lab report, I have met a couple of course learning outcomes. By working with my group to pick this topic, I developed and engaged in the collaborative and social aspects of writing processes. 

AUDIENCE PROFILE SHEET

Reader’s Name:   Marine biologists 

Reader’s Job Title:  Most likely scientists/individuals interested in the ocean ecosystem 

Education:  Working towards a degree in Marine Biology 

Professional Experience:  Has experience studying the ocean 

Job Responsibilities:  Unknown 

Personal Characteristics:  Likes to explore water 

Cultural Characteristics:  No specificity 

Attitude Toward the Writer:  Curious to learn  

Attitude Toward the Subject:  Curious to learn 

Expectations About the Subject:  Expect to learn about the differences in densities of water around Manhattan 

Expectations About the Document:  Professional Lab report 

Reasons for Reading the Document:  Need to know they density of certain Manhattan water supplies 

Ways of Reading the Document:

Skim it _X__    Study It ___     Read a portion of it ___                      Which portion?

Modify it and submit it to another reader ___

Attempt to implement recommendations ___

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

Use it to create another document ___

Other ___        Explain

Reading Skills:  Mediocre

Reader’s Physical Environment:  No Preference