Ocean Acidification Lab
Collaborators:
Melissa Daria
Lindsay Carter
Emily Davis
Princess Evuka
Introduction:
Ocean acidification is the reduction in the ocean's pH caused primarily by carbon dioxide. According to the NAtinal Resources Defense Council, "Seawater is not an acid because it measures above neutral on the pH scale. But adding carbon dioxide lowers the pH and causes it to shift towards the acidic end of the scale." In our lab, we observed this process by testing the effects of carbon dioxide and calcium carbonate on ocean water and distilled water.
Problem:How does carbon dioxide affect the pH of water?
Hypothesis: If there is an increased amount of carbon dioxide interacting with water. then that water's pH will decrease, therefore increasing ocean acidity.
Parts of experiments:
Control group: Distilled water
Experimental group: Ocean water
Dependent variable: Indicated pH by universal indicator
Independent variable: Water type tested
Controlled variables: test tubes, balloon, room temperature, water amount
Materials:
Methods:
1. Use a graduated cylinder to measure 10 ML of ocean water. Pour it into test tube #1 and add a pipet full of universal indicator. Stir and record the pH.
2. Use a graduated cylinder to measure 10 ML of distilled water. Pour it into test tube #2 and add a pipet full of universal indicator. Stir and record the pH.
3. Inflate the balloon and hold it securely tight.
4. Insert the tip of the straw into the neck of the balloon, while holding the elastic secure so air will not escape.
5. Place the other end of the straw in sample #1, and release the pressure on the balloon's neck to allow air to move through the straw.
6. Begin timing as the pressure is released, and stop timing once the color changes.
7. Record data and repeat procedure on sample #2.
8. Add crushed calcium carbonate to both samples and record color change.
Data:
Melissa Daria
Lindsay Carter
Emily Davis
Princess Evuka
Introduction:
Ocean acidification is the reduction in the ocean's pH caused primarily by carbon dioxide. According to the NAtinal Resources Defense Council, "Seawater is not an acid because it measures above neutral on the pH scale. But adding carbon dioxide lowers the pH and causes it to shift towards the acidic end of the scale." In our lab, we observed this process by testing the effects of carbon dioxide and calcium carbonate on ocean water and distilled water.
Problem:How does carbon dioxide affect the pH of water?
Hypothesis: If there is an increased amount of carbon dioxide interacting with water. then that water's pH will decrease, therefore increasing ocean acidity.
Parts of experiments:
Control group: Distilled water
Experimental group: Ocean water
Dependent variable: Indicated pH by universal indicator
Independent variable: Water type tested
Controlled variables: test tubes, balloon, room temperature, water amount
Materials:
- 2 test tubes
- Universal indicator
- Ocean water
- Distilled water
- Balloon
- Plastic pipet
Methods:
1. Use a graduated cylinder to measure 10 ML of ocean water. Pour it into test tube #1 and add a pipet full of universal indicator. Stir and record the pH.
2. Use a graduated cylinder to measure 10 ML of distilled water. Pour it into test tube #2 and add a pipet full of universal indicator. Stir and record the pH.
3. Inflate the balloon and hold it securely tight.
4. Insert the tip of the straw into the neck of the balloon, while holding the elastic secure so air will not escape.
5. Place the other end of the straw in sample #1, and release the pressure on the balloon's neck to allow air to move through the straw.
6. Begin timing as the pressure is released, and stop timing once the color changes.
7. Record data and repeat procedure on sample #2.
8. Add crushed calcium carbonate to both samples and record color change.
Data:
Conclusion:
The average pH of surface ocean water is 8.1, according to 1994 data. Our data findings were similar to this, although there may have been a slight error in comparing the colors on the pH scale. Both the distilled water and ocean water had similar changes when exposed to CO2, however the distilled water reacted quicker to the CO2 than the ocean water. This may be because oceans are more equipped to absorb and tolerate certain amounts of CO2 before a chemical change occurs. When the calcium carbonate was added, both solutions bubbled and changed colors. However, the distilled water's color changed much more drastically than the ocean water, which may again be attributed to ocean CO2 absorption. Although the balloon experiment displayed how ocean acidification happens, it's not an accurate model of ocean absorption of CO2, as there was room for error in many parts of the lab. For example, the human eye is not the most accurate tool for assessing pH as color perception varies from person to person. Also, manually removing the balloon proved to be challenging for maintaining accuracy of timing with color change.
Citations:
"Ocean Acidification." Nrdc.org. Natural Resources Defense Council, n.d. Web. 16 Apr. 2015.
The average pH of surface ocean water is 8.1, according to 1994 data. Our data findings were similar to this, although there may have been a slight error in comparing the colors on the pH scale. Both the distilled water and ocean water had similar changes when exposed to CO2, however the distilled water reacted quicker to the CO2 than the ocean water. This may be because oceans are more equipped to absorb and tolerate certain amounts of CO2 before a chemical change occurs. When the calcium carbonate was added, both solutions bubbled and changed colors. However, the distilled water's color changed much more drastically than the ocean water, which may again be attributed to ocean CO2 absorption. Although the balloon experiment displayed how ocean acidification happens, it's not an accurate model of ocean absorption of CO2, as there was room for error in many parts of the lab. For example, the human eye is not the most accurate tool for assessing pH as color perception varies from person to person. Also, manually removing the balloon proved to be challenging for maintaining accuracy of timing with color change.
Citations:
"Ocean Acidification." Nrdc.org. Natural Resources Defense Council, n.d. Web. 16 Apr. 2015.