Day Two: Mussels Lab Partner: Brittany Rummel Date: January 13, 2016
Purpose: To see the change in mussels and pH in vinegar and saltwater after a period of time.
Procedure:
Gather 4 mussel shells and one will have an "E", one will have a "C", and the others will be left untreated.
Record your observations of the 2 mussels with writing on them.
Find the mass of the all 4 shells, then record.
Pour 150 mL of vinegar and saltwater into separate beaker that fills at least 500 mL.
Test the pH levels of both liquids using a pH strip
Set time to 30 minutes.
Place the mussel with a "C" to the saltwater and the mussel with an "E" to the vinegar, AT THE SAME TIME.
After the 15 minutes, and record the appearance of the mussels.
After the whole 30 minutes take both mussels out of the 2 liquids and record your obersavtions.
Find the mass of the mussels that you pulled out and compare the differences.
Test the pH of both liquids, then compare and record the differences.
On the remaining 2 shells, make sure one has had a low exposure (4-6 hours) to vinegar and the other a high exposure (16-18 hours). Label if needed. (We labeled one "L" and the other, "H")
Test the strength of each shell by gently placing textbooks one at a time until it breaks. Record how many textbooks it will take in order to do so.
Observations:
E: Initial: Bubbles forming on the outer shell After 15 minutes: seems to be more bubbles After total 30 minutes: no difference -Went down .1 g after 30 minutes (became 2.1 g)
C: Initial: bubbles coming to the surface After 15 minutes: bubbles on the shell, as well as going up After total 30 minutes: bubbles all over the shell and foam on top - stayed the same weight (2.1 g)
L: -2 textbooks to crush - stayed the same weight (1.7 g)
H: -1 textbook to crush - stayed the same weight (1.2 g)
pH of both liquids: no difference, but vinegar was 1.0 and saltwater was 5.0
Conclusion: We found that when the water in the ocean fully acidifies the sea creatures outer layer may be stronger on certain animals. It may end up harming other sea creatures.
Error Analysis: My partner and I forgot to take note of our observations at the 15 minute mark.
Post- Lab Questions:
Q: When you immersed the shells in vinegar, how did you know that a reaction was happening? A: I knew a reaction was happening once Brittany placed the shell in vinegar because it was clear that there was bubbling coming from the shell.
Q: What was the chemical reaction that you just observed? The chemical formula for acetic acid (vinegar) is C2H402 A:C2H402 +
Q: What type of gas is being produced by this reaction? A: I'm pretty sure it's carbon dioxide being produced.
Q: How is this reaction similar/different from the reaction during the bubbles protocol? A: I believe that this reaction is similar to the bubble lab because both experiments show how changing the pH of salt water in the ocean will affect the water and living organisms.
Q: How did observing the shells in vinegar relate to how animals are affected by a lower pH of ocean water? A: The shell showed that an organism that is in an acidic base could change the color and shape, but may also release other gases into the ocean.
Q: How would shelled organisms be affected by a lower pH of ocean water? A: It would be affected because the amount of hydrogen objects need to live can be affected.
Q: What are the primary functions of shells for these animals? Q: It will make the shelled creatures have a stronger outer layer that could protect them.