Lab investigation

**Lab: Investigation - How changes in ocean water affect oyster shells 

Question: What is the impact of the changing seawater on oysters?

Introduction: Have you ever wondered what seashells are made of? Oysters are a type of bivalve mollusk that uses shells as a protective outer exterior.  Seashells contain a mineral called calcium carbonate. Because of the nature of calcium carbonate, some seashells can be affected by increased carbon dioxide in the air. In our investigation, we are going to observe how changes in the water can affect seashells and therefore the survival rate of oysters.  

Materials:

  • Scale

  • pH paper

  • Glass jars 

  • Oyster shells

  • Ocean water

  • Seltzer water

  • Vinegar

  • 100 mL Graduated cylinder

Procedure:

  1. Obtain goggles and gather all materials. 

  2. Teacher will assign one solution to test & to investigate with your shell. 

  3. ½ seawater + ½ vinegar

  4. ½ seawater + ½ seltzer water, 

  5. ⅓ seawater, ⅓ seltzer water + ⅓ vinegar

  6. Using your graduated cylinder and some water, determine the volume of your glass jar.

  7. Determine how much of each substance you will need to make your assigned solution. 

  8. Use a graduated cylinder and make your solution to test by adding the appropriate amount of seawater and other solution(s) to a jar.

  9. After the solution has been made, take the pH of the solution by dipping pH paper in your test solution and record the pH value in the data table for “reading 1”.

  10. Using the scale in the back, mass your solution without the lid and record it in the data table.

  11. Using the scale, mass a dried oyster shell and record in the data table.

  12. Place your oyster shell in the solution and place the solution on a scale.  Mass your solution and oyster shell and record in the data table in the “reading 1” row.

  13. Over the course of the next couple of weeks, you will take 5 readings of the pH and massings of your solutions.

  14. After the fifth reading, dry your oyster shell.  Once completely dry, mass the oyster shell and record it in the data table.

Data: 

  • Solution assigned: Soln #3

  • Initial Mass of Solution + jar without the lid 243.59g

  • Take a photo of shell and insert

  • Reading 1: Initial Shell Mass 4.10g

Readings Date Shell Mass (g)
+ Solution Mass w/out Lid		 Observations pH
1 2-17-2023 246.58g Black shell and shell sinks to the bottom of the jar. 3.0
2 2-27-2023 244.44 Kinda white spots around the shell surface
3 3-10-2023 244.03 White Shell
  • Reading 5: Final Shell Mass 4.10

Calculations:  

  • Calculate the change in mass (Δm):  Δm = Final mass - initial mass

  • Calculate the percent change of mass:  Percent (%) change =   Δm initial mass x 100

  • Calculate the percent change per day:  % change # days

Class Data:

Group Solution Δm % change % change/day
0 ocean water 0.00 0.00 0.00
1 ½ ocean water + ½ vinegar
2 ½ ocean water + ½ vinegar
3 ½ ocean water + ½ vinegar
4 ½ ocean water + ½ seltzer
5 ½ ocean water + ½ seltzer
6 ½ ocean water + ½ seltzer
7 ⅓ ocean water + ⅓ vinegar + ⅓ seltzer
8 ⅓ ocean water + ⅓ vinegar + ⅓ seltzer
9 ⅓ ocean water + ⅓ vinegar + ⅓ seltzer

Graphs: 

Create a scatter plot graph with a trendline of your data that compares the change in mass over time.  (Paste below)

Create a visual of the class results using a bar graph of each solution and percent change per day.  Use error bars to capture all the data.  (Paste below)

Analysis: After the experiment is complete, write a CER (CLAIM, EVIDENCE, AND REASONING) paragraph.  State your claim.  Provide at least 2-3 pieces of evidence.  Explain “the how and why” your evidence relates to your claim through your reasoning.

Last update: June 5, 2023
Created: June 5, 2023