• Quick retrieval from earlier learning (The greenhouse effect and climate change; Interpreting data from tables and graphs). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. What does the greenhouse effect do? (It makes oxygen / It makes holes in the atmosphere / It reflects all sunlight back to space / Greenhouse gases trap some heat, keeping Earth warm enough for life) → Greenhouse gases trap some heat, keeping Earth warm enough for lifePrompt: Without it, Earth would be much colder.
2. Study: Cooling coffee. Time (min) → Temperature (°C) 0 → 88 5 → 78 10 → 68 15 → 58 20 → 48 Estimate the value at 12.5, assuming the pattern between neighbouring points is a straight line. → 63Prompt: 12.5 lies halfway between 10 and 15.
3. Before 1800, carbon dioxide in the air was about 280 parts per million (ppm). Recently it was about 420 ppm. By what percentage has it increased? Give a whole number. → 50 %Prompt: First find the increase.

• Show today's forecast and ask what it means for the class and how forecasters know.
• Share the objective: Analyse climate data: CO₂ records and temperature trends. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Annual mean CO₂ at the Mauna Loa observatory was about 317 ppm in 1960 and about 414 ppm in 2020. What was the mean rate of increase, in ppm per year? Give 1 decimal place.
• Step 1: (414 − 317) ÷ (2020 − 1960) = 97 ÷ 60 = 1.62
• Step 2: So the answer is: 1.6
• Answer: 1.6
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Annual mean CO₂ at the Mauna Loa observatory was about 326 ppm in 1970 and about 390 ppm in 2010. What was the mean rate of increase, in ppm per year? Give 1 decimal place. → 1.6Prompt: rate = change in CO₂ ÷ change in time
2. Pre-industrial CO₂ was about 280 ppm. In the 2020s it is above 420 ppm. Roughly what percentage increase is this? (about 150 % / about 5 % / about 50 % / about 15 %) → about 50 %Prompt: (420 − 280) ÷ 280 × 100

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. A website claims "the climate has always changed, so today's warming is natural". Which response is best supported by evidence? (Natural changes cannot happen / There has been no warming since 1900 / The claim proves humans have no effect / Past changes were mostly slower and had natural causes; today's rapid warming matches the rise in CO₂ from human activity) → Past changes were mostly slower and had natural causes; today's rapid warming matches the rise in CO₂ from human activityPrompt: Look at the speed and the cause of the change.
2. Annual mean CO₂ at the Mauna Loa observatory was about 369 ppm in 2000 and about 421 ppm in 2023. What was the mean rate of increase, in ppm per year? Give 1 decimal place. → 2.3Prompt: rate = change in CO₂ ÷ change in time

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-11.