The changing ocean
Climate and coasts
Three free lessons for ages 13 to 18
The ocean has absorbed over 90% of the extra heat trapped by greenhouse gases. Students model warming and acidification with simple experiments, calculate coral heat stress the way NOAA does, and debate what 1.5 °C versus 2 °C means for reefs.
- Ages
- 13 to 18
- Time
- About an hour per lesson
- Subjects
- Science, maths and geography
- Hands-on
- Two experiments, a degree heating weeks calculation and a structured debate
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Lesson 1: A warming ocean
How the ocean absorbs heat, a sand and water experiment, and calculating coral heat stress with degree heating weeks.
- Ages
- 13 to 18 (grades 8 to 12)
- Time
- 60 to 75 minutes
- You need
- Per group two cups, sand, water, two thermometers and a lamp, plus one DHW worksheet per student
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Lesson 2: An acidifying ocean
How carbon dioxide acidifies seawater, two simple experiments, and what it means for shells and corals.
- Ages
- 13 to 18 (grades 8 to 12)
- Time
- 60 minutes, plus a 24-hour wait for experiment 2
- You need
- Per group: red cabbage indicator or universal indicator, cups, straws, eggshell or chalk, water, soda water, vinegar, a balance
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Lesson 3: Bleaching, change and hope
Global bleaching data, future projections, what helps reefs, and a structured debate.
- Ages
- 13 to 18 (grades 8 to 12)
- Time
- 60 minutes
- You need
- One debate planner per pair
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Bring your students to the reef
We host school groups at our base in Zamboanguita, Negros Oriental, for diving or snorkelling, beach clean-ups and tree planting alongside our conservation team. Every visit follows our child protection policy.