• 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 holes in the atmosphere / It reflects all sunlight back to space / It makes oxygen / 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: Solubility of a salt in water. Temperature (°C) → Solubility (g per 100 g water) 0 → 12 20 → 16 40 → 20 60 → 24 80 → 28 Estimate the value at 10, assuming the pattern between neighbouring points is a straight line. → 14Prompt: 10 lies halfway between 0 and 20.
3. Before 1800, carbon dioxide in the air was about 280 parts per million (ppm). Recently it was about 400 ppm. By what percentage has it increased? Give a whole number. → 43 %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. A website claims "the climate has always changed, so today's warming is natural". Which response is best supported by evidence? (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 / 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 activityPrompt: Look at the speed and the cause of the change.

• 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. / Arctic sea ice in summer has shrunk since satellite records began in 1979. / Melting sea ice is the main cause of sea-level rise. / Sea level is rising as oceans warm and land ice melts.) → Melting sea ice is the main cause of sea-level rise.Prompt: What is the difference between weather and climate?
2. Annual mean CO₂ at the Mauna Loa observatory was about 369 ppm in 2000 and about 414 ppm in 2020. 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.