Ocean Acidification Labs! May 10
Hello Everyone,
Today, we explored ocean acidification as a way humans are impacting nature. As a result of increased carbon dioxide in our atmosphere from human activities, and because the Earth’s trees and plants cannot absorb all of the excess, there is a lot of extra carbon dioxide! Not only is it contributing to global warming and climate change, but it is also being absorbed by our oceans. As more carbon dioxide is absorbed, it changes the alkalinity of the ocean and the pH. This means organisms who rely on a specific pH are having difficulty and that their shells, made of calcium, are deteriorating in the over-acidic water.
For more information on this, we watched a video on ocean acidification, narrated by Sigourney Weaver, which originally aired on Discovery Planet Green.
Then, we experimented with the pH scale by testing a wide variety of household liquids and types of water available to us: lemon juice, vitamin C (Redoxon), oxyclean, 2% milk, salt water, distilled water, tap water, seltzer water, lemon-lime soda, baking soda, vinegar, borax, and aspirin. To test the acidity of each, we used red cabbage extract, which is a natural anthocyanin that can be used to test acidity levels. For more information on how to prepare your own red cabbage extract, see these links:
Red Cabbage Indicator Experiment (complex version, with higher chemistry)
Science Project Lab on Red Cabbage and Acidity
We had a rainbow of colours as our indicator changed colour in each of the substances. We predicted the possible pH ahead of time, making a hypothesis, and then recorded the actual results. Finally, we had a discussion, making conclusions about the proper pH for organisms to survive in fresh or salt water. If you have an aquarium or visit pet stores, you may know about this already!
We then talked about alkalinity, which is the water’s ability to hold a consistent pH and is measured in mg/L or ppm. We discovered alkalinity increases as the pH increases. In other words, as the ocean gets more acidic, alkalinity goes down, and the water has a harder time holding the appropriate level of pH. To test this, we took four water samples (salt water, distilled water, tap water, seltzer water) and tested alkalinity using Tetra test strips for aquariums. Then we measured the pH of each water. Finally, we took straws to blow bubbles into the water, adding CO2, to see if we could affect the colour from the indicator and make the water more acidic.
Thank you everyone for your great work on the lab!
Students who signed up for the ABEL TEST completed their tests this afternoon. I will let you know when I am able to share results with you, but I know they have to be reported to the District first. Thank you for your patience in advance.
If you are taking the GAUSS TEST, then you will do that on May 15th, Monday. Please study ahead of time and be prepared by having a calculator for class.
We also did some exploring outside, trying to identify local plants around the school.
For tonight:
- Please work on our Sue Coccia drawing art if you need to catch up.
- Remember to turn in your 20 BOB Questions, poems, and journal which are now overdue.
- Read the rules for the Biodiversity Card Game so you can play it tomorrow with a partner.
- Take a look at yesterday’s blog post for websites and articles on oceans that we won’t have time for in class.
- And LIBRARY is tomorrow, so bring your books!
Have a good evening!