The other carbon problem

Lesson overview

This lesson introduces ocean acidification, the other carbon problem. The ocean absorbs about 25% of human-produced carbon dioxide from the atmosphere. This helps to mitigate climate change but is not without its negative consequences for the ocean.

This is a practical lesson where students will develop their working scientifically skills and develop their literacy by writing a scientific conclusion using the ‘Point Evidence Explain’ technique from English.

Learning outcomes
  • Describe patterns in results
  • Investigate how carbon emissions change ocean chemistry
  • Describe the process of ocean acidification
  • Write a scientific conclusion
Lesson steps

1. Context of the learning (5 mins)

The first five slides outline the learning objectives and connect this lesson to wider learning about the ocean and climate.

2. Patterns and correlations (15 mins)

This section of the lesson focuses on developing students’ knowledge around spotting patterns and determining correlations. The section takes students through three graphs that show different data sets and asks ‘What’s the relationship?’ Show these slides 7 to 12 to students, asking them to spot the relationship if there is one and to describe it.

Slide 13 introduces the concept of correlation. Students may wish to note this definition as well as the difference between a positive and negative correlation shown by referencing the two graphs mentioned before.

This section moves to a whole class discussion on the difference between correlation and causation. Slide 14 posits this question, “Do ice cream sales cause shark attacks?” Of course, the answer is “no”, both tend to occur in higher numbers during warm summer months. Ask students how they might test this using slide 16. An unpopular way might be to ban ice cream and to see what happened to the frequency of shark attacks.

Introduce the idea that scientists are not just interested in patterns but the underlying cause of these patterns. Point-Evidence-Explain is a frame that students may know from English or other subjects and is used in science to add the necessary rigour to their conclusions. Slides 17 to 21 provide a worked example to share with students.

3. Investigating ocean acidification (15 mins)

The Activity Overview Ocean acidification investigation guides the set up and running of the practical investigation. Review the health and safety notes with students (highlights are noted on the Activity Sheet Ocean acidification investigation).

Hand out the Activity Sheet and Student Sheet Investigating ocean acidification. Students should complete questions 1-4 individually and then work in pairs for the practical investigation. Answers are included on the Answer Sheet Investigating ocean acidification.

Run through the practical instructions using slide 26 and the discussion questions can be debriefed using slide 27.

4. Ocean acidification (10 mins)

Slides 29 to 31 remind students of the importance of knowing about ocean acidification. Students should be able to describe the process using the words on the board. This can be done for higher ability students using slide 32 and then with more support using slide 33 for lower ability students. Review the process of ocean acidification using slide 34. Slide 35 shows the chemical equation

5. Writing a conclusion (10 mins)

There are two options for this section. Lower ability students can read and correct the example conclusion on the second page of Student Sheet Investigating ocean acidification. Higher ability students can work on their own conclusion using the PEE frame. Set this activity using slide 37, then review it using the model answer on slide 38.

6. Learning review (5 mins)

Review the learning objectives and the reality of ocean acidification using slides 39 and 40.