• 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. Which of these is a greenhouse gas? (oxygen / methane / nitrogen / argon) → methanePrompt: Cattle and rice paddies release it.
2. Study: Cooling coffee. Time (min) → Temperature (°C) 0 → 87 5 → 77 10 → 67 15 → 57 20 → 47 Estimate the value at 12.5, assuming the pattern between neighbouring points is a straight line. → 62Prompt: 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 410 ppm. By what percentage has it increased? Give a whole number. → 46 %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 354 ppm in 1990 and about 414 ppm in 2020. What was the mean rate of increase, in ppm per year? Give 1 decimal place. → 2Prompt: rate = change in CO₂ ÷ change in time
2. How do scientists know CO₂ levels from hundreds of thousands of years ago? (from satellite photos of the past / from old newspapers / they guess / from air bubbles trapped in ice cores from Antarctica) → from air bubbles trapped in ice cores from AntarcticaPrompt: Snow traps tiny samples of air as it turns into ice.

• 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. Climate evidence: which statement is NOT true? (Global average surface temperature has risen by more than 1 °C since the late 1800s. / Most of the extra CO₂ comes from volcanoes. / Sea level is rising as oceans warm and land ice melts. / Arctic sea ice in summer has shrunk since satellite records began in 1979.) → Most of the extra CO₂ comes from volcanoes.Prompt: What is the difference between weather and climate?
2. A website claims "the climate has always changed, so today's warming is natural". Which response is best supported by evidence? (The claim proves humans have no effect / Natural changes cannot happen / Past changes were mostly slower and had natural causes; today's rapid warming matches the rise in CO₂ from human activity / There has been no warming since 1900) → 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.

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