We began class with a discussion of of the reading from yesterday. The discussion focused on helping students understand how to read the questions, how to formulate a response, and the expectation of the quality and depth of thinking expected of a high school student of biology. Notes from the white boards are pictured below:
After the discussion, students conducted an experiment designed to test the effect of exercise on the amount of carbon dioxide exhaled. The experiment introduced students to the concept of cellular respiration (vocabulary they will learn soon) by studying the intersection of the cardiovascular and respiratory body systems. Students measured pH as a surrogate measure of carbon dioxide output by exhaling into a straw placed in a cup of distilled water. To measure pH, students used probeware connected to hand-held computers. They measured the pH of the water before and after exercise, writing down their procedure and optimizing the procedure during the class period. Students obtained data demonstrating a correlation between exhaled carbon dioxide and decreasing pH.
Students wishing to understand the chemistry behind our experiment should visit NOAA’s Ocean Acidification website. The Smithsonian Institute also has an excellent collection of content explaining ocean acidification that includes some videos about how sea life is affected by increasing carbon dioxide in the atmosphere.
Today we are working in the computer lab so students can learn more abut the process of ocean acidification, the effect on sea life, and to model how the pH is predicted to change during their lifetimes. Students will use the website Our Acidifying Ocean and will complete pages 1 and 2 of the worksheet.
We kicked off the lesson with an entry task focused on why we use fossil fuel combustion (to produce energy). Students were then asked to consider one unintended consequence of fossil fuel combustion (releasing carbon dioxide into the atmosphere). We followed that discussion with a video about ocean acidification (below) before concluding the lesson with an experiment in which students re-created the conditions of ocean acidification by measuring the change in pH after exhaling through a straw placed in water for one minute.
We have spent the last week learning about the processes that are driving ocean acidification, learning to use gas sensors and pH probes, and thinking hard about how we can use our local resources at Seahurst Park to advance our learning. Over the next two days, students will create a final project which will include the following:
1. A carefully designed, conducted, and analyzed experiment demonstrating the effect of increased atmospheric carbon dioxide on the stakeholder group they selected.
2. Research and analysis of scientific data to support the group’s model of how increased atmospheric carbon dioxide is affecting subsystems relevant to the global carbon cycle.
3. A presentation summarizing their findings. Each student must create and present presentation content to share at the Global Ocean Acidification Summit to be held tomorrow afternoon.
For part 2, students are encouraged to visit Lesson 5b of the Baliga Lab Ocean Acidification unit and visit the links provided that are relevant to their area of research.