As a high school or introductory undergraduate Chemistry or Environmental Sciences teacher, you can use these computer based tools to teach a practical component of environmental chemistry paper i.e. the determination of dissolved oxygen in the given sample of water.
In this lesson plan, students will be introduced to the term ‘dissolved oxygen’ and understand the correlation between increase in global temperatures and declining oxygen levels in the oceans. The students will further learn about the impact of low oxygen levels on aquatic life and food webs. Thus, the use of this lesson plan allows you to integrate the teaching of a climate science topic with a core topic in Chemistry or Environmental Sciences.The tools in this lesson plan will enable students to:
Teacher-contributed lesson plan by Dr. Shefali Shukla (Department of Chemistry, Sri Venkateswara College, University of Delhi, New Delhi), and Dr. Shikha Gulati (Department of Chemistry, Sri Venkateswara College, University of Delhi)
Want to know more about how to contribute? Contact us.Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.
Video (5 min)
Use the video micro-lecture titled, “Dissolved Oxygen” by Massachusetts Institute of Technology to help students understand the meaning of dissolved oxygen. Use this video to explain the various sources which maintain the oxygen levels in the water body, like photosynthesis by plants and phytoplanktons. Further discuss how the increase in global temperatures is responsible for decreasing the oxygen holding capacity of water bodies. This video can also be used to state factors, other than global warming, that are responsible for the declining oxygen levels in water and the precautions which can be taken to keep the oxygen levels in check .
Video (5 min)
This video micro-lecture titled, “Ocean Deoxygenation: Our Ocean’s Oxygen Supply & Demand Issue” produced by Ocean Scientist for Informed Policy (OSIP) can be used to further emphasize how climate change is causing an imbalance in the oxygen demand and supply in the oceans. This alteration in ocean dynamics through decreasing oxygen supply also results in an increase in the biological oxygen demand (BOD). Increasing BOD is responsible for further lowering of oxygen levels in the oceans negatively impacts the aquatic ecosystem. The video can also be used to explain the seriousness of the concern through some oxygen minimum zones which are already present in some of the oceans and are expanding horizontally as well as vertically. These zones already have a negative impact on those marine lives which are more sensitive to this low oxygen situation.
Reading (10 mins)
This reading titled, “Guest post: How global warming is causing ocean oxygen levels to fall” briefly explains the dangers of deoxygenation and the possible reasons of global warming which is directly proportional to the marine oxygen loss. In this reading material the charts depicting the changing oxygen levels over the years have been presented. Most importantly, in this reading material, there is an embedded link that takes the readers to the latest review published by “Nature Geoscience” which discusses the Drivers and Mechanisms of oxygen deoxygenation
Classroom/Laboratory Activity (60 min)
Winkler’s method is the most common titrimetric method used to estimate the amount of dissolved oxygen in the water sample. In this method, the oxygen present in the water sample is used to oxidize iodide ions to iodine, quantitatively. This classroom/laboratory activity titled, “Determination of Dissolved Oxygen by Winkler Titration” explains the principle, apparatus and chemicals required, the reactions involved and step by step procedure to be followed by the students and how to calculate the oxygen levels using these results.
Use this lesson plan to help your students find answers to:
| 1 | Reading (5-8 min) | A reading material at Scientific American magazine which relates the
increasing CO2 levels in the atmosphere to the decreasing oxygen in water
bodies
This can be accessed here |
| 2 | Reading (5-8 min) | Another press release by UNESCO which talks about the raising concern
about the low oxygen levels in oceans.
This can be accessed here. |
| 3 | Video (10 min) | This video explains the experimental determination of effect of salinity and
temperature on Dissolved Oxygen. As global temperature increases, the
solubility of salts in water also increase which impacts the DO levels.
This can be accessed here. |
| 4 | Reading (5-7 min) | Reading at Webpage of IOC-UNESCO Global Ocean Oxygen Network (GO2NE) on Declining oxygen in the world’s ocean: 15 things to knowThis can be accessed here. |
| 5 | Reading (60 min) | Read the sections 2.1, 3.1, 3.2 and 3.3
This can be accessed here. |
| 1 | Video lecture-1 “Dissolved Oxygen” | Massachusetts Institute of Technology, You Tube |
| 2 | Video lecture-2 “Dissolved Oxygen” | Natalya Gallo at the Scripps Institution of Oceanography, you tube |
| 3 | Reading (PDF) | https://www.carbonbrief.org/ |
| 4 | Laboratory Experiment | Massachusetts Institute of Technology |
| 5 | Additional Resources | 1. Article at Scientific American magazine 2. UNESCO 3. Kilroy Academy, you tube 4. of IOC-UNESCO Global Ocean Oxygen Network (GO2NE) 5. The International Union for Conservation of Nature |
| Grade Level | High School, Undergraduate |
| Discipline | Chemistry, Environmental Sciences |
| Topic(s) in Discipline | Environmental Chemistry, Hydrosphere, Dissolved Oxygen, Water Pollution, Analytical Chemistry, Industrial Chemistry |
| Climate Topic | Climate and the Atmosphere, Climate and the Biosphere, Climate and the Hydrosphere |
| Location | Global |
| Language(s) | English |
| Access | Online |
| Approximate Time Required | 90-120 mins |
| Resource Download |
Here is a step-by-step guide to using this lesson plan in the classroom/laboratory. We have suggested these steps as a possible plan of action. You may customize the lesson plan according to your preferences and requirements.
1.Introduce the topic by playing a video micro-lecture
Video (5 min)
Use the video micro-lecture titled, “Dissolved Oxygen” by Massachusetts Institute of Technology to help students understand the meaning of dissolved oxygen. Use this video to explain the various sources which maintain the oxygen levels in the water body, like photosynthesis by plants and phytoplanktons. Further discuss how the increase in global temperatures is responsible for decreasing the oxygen holding capacity of water bodies. This video can also be used to state factors, other than global warming, that are responsible for the declining oxygen levels in water and the precautions which can be taken to keep the oxygen levels in check .
2. Explore the topic further by playing a video micro-lecture
Video (5 min)
This video micro-lecture titled, “Ocean Deoxygenation: Our Ocean’s Oxygen Supply & Demand Issue” produced by Ocean Scientist for Informed Policy (OSIP) can be used to further emphasize how climate change is causing an imbalance in the oxygen demand and supply in the oceans. This alteration in ocean dynamics through decreasing oxygen supply also results in an increase in the biological oxygen demand (BOD). Increasing BOD is responsible for further lowering of oxygen levels in the oceans negatively impacts the aquatic ecosystem. The video can also be used to explain the seriousness of the concern through some oxygen minimum zones which are already present in some of the oceans and are expanding horizontally as well as vertically. These zones already have a negative impact on those marine lives which are more sensitive to this low oxygen situation.
3. Demonstrate how it is related to climate change through this reading
Reading (10 min)
This reading titled, “Guest post: How global warming is causing ocean oxygen levels to fall” briefly explains the dangers of deoxygenation and the possible reasons of global warming which is directly proportional to the marine oxygen loss. In this reading material the charts depicting the changing oxygen levels over the years have been presented. Most importantly, in this reading material, there is an embedded link that takes the readers to the latest review published by “Nature Geoscience” which discusses the Drivers and Mechanisms of oxygen deoxygenation.
4. Laboratory Activity: Determination of Dissolved Oxygen by Winkler’s titration method
Classroom/Laboratory Activity (60 min)
Winkler’s method is the most common titrimetric method used to estimate the amount of dissolved oxygen in the water sample. In this method, the oxygen present in the water sample is used to oxidize iodide ions to iodine, quantitatively. This classroom/laboratory activity titled, “Determination of Dissolved Oxygen by Winkler Titration” explains the principle, apparatus and chemicals required, the reactions involved and step by step procedure to be followed by the students and how to calculate the oxygen levels using these results.
5. Field Activity (optional)
Classroom/Laboratory Activity (Nature Walk) (10- 20 min)
To better understand the structure and functioning of the pond ecosystem, students can construct an artificial or man-made pond to help drain fields during rain, recycle nutrients, and reduce the amount of nitrates and phosphates. Students would be able to critically analyze the pond ecology, and how alterations due to human activities impacts the aquatic ecosystem. This can be used to come up with conservation strategies to maintain ecological balance and prevent acidification of the pond.
Use this lesson plan to help your students find answers to:
| 1 | Reading (5-8 mins) | A reading material at Scientific American magazine which relates the This can be accessed here. |
| 2 | Reading (5-8 mins) | Another press release by UNESCO which talks about the raising concern about the low oxygen levels in oceans. This can be accessed here. |
| 3 | Video (10 mins) | This video explains the experimental determination of effect of salinity and temperature on Dissolved Oxygen. As global temperature increases, the solubility of salts in water also increase which impacts the DO levels. This can be accessed here. |
| 4 | Reading (5-7 mins) | Reading at Webpage of IOC-UNESCO Global Ocean Oxygen Network (GO2NE) on Declining oxygen in the world’s ocean: 15 things to know This can be accessed here. |
| 5 | Read (60 mins) | Read the sections 2.1, 3.1, 3.2 and 3.3 This can be accessed here. |
| 1 | Video lecture-1 “Dissolved Oxygen” | Massachusetts Institute of Technology, You Tube |
| 2 | Video lecture-2 “Dissolved Oxygen” | Natalya Gallo at the Scripps Institution of Oceanography, you tube |
| 3 | Reading (PDF) | https://www.carbonbrief.org/ |
| 4 | Laboratory Experiment | Massachusetts Institute of Technology |
| 5 | Additional Resources | 1. Article at Scientific American magazine |
