• Quick retrieval from earlier learning (Evaluating experiments (research summaries)). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Experiment 1: Seeds were kept at 10 °C, 20 °C and 30 °C, all watered daily, and the number that germinated was counted. Experiment 2: Seeds were kept at 20 °C and given 0, 5 or 10 mL of water a day. In Experiment 2, which variable was changed on purpose? (the number of seeds that germinated / the temperature / the volume of water / the colour of the pots) → the volume of waterPrompt: Look only at the description of Experiment 2.
2. Experiment 1: Seeds were kept at 10 °C, 20 °C and 30 °C, all watered daily, and the number that germinated was counted. Experiment 2: Seeds were kept at 20 °C and given 0, 5 or 10 mL of water a day. Which variable was kept constant in Experiment 2 but changed in Experiment 1? (the volume of water / the colour of the pots / the number of seeds that germinated / the temperature) → the temperaturePrompt: What was tested in Experiment 1?
3. A study finds a result with only 3 samples. What is the best next step? (Use fewer samples / Publish it as proof / Change the data / Repeat with a larger sample) → Repeat with a larger samplePrompt: Small samples can give misleading results.

• Show a simple experiment with one thing changed and ask what makes it a fair test.
• Share the objective: Comparing scientific explanations (conflicting viewpoints). Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Two students explain why a ball rolling on a flat floor eventually stops. Student 1: Objects naturally slow down and stop when nothing keeps pushing them. Student 2: Friction and air resistance act against the motion; with no resistive forces, the ball would keep moving at a steady speed. Which student's view agrees with Newton's first law?
• Step 1: Newton's first law: an object keeps moving at constant velocity unless a resultant force acts.
• Step 2: So the answer is: Student 2
• Answer: Student 2
• 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. What makes a scientific explanation stronger than another? (It is more complicated / More people like it / It explains more of the evidence and makes predictions that are confirmed / It is older) → It explains more of the evidence and makes predictions that are confirmedPrompt: Scientists judge ideas by evidence.
2. Two students explain why a metal spoon in hot soup feels hotter than a wooden spoon in the same soup. Student 1: The metal spoon is at a higher temperature than the wooden spoon. Student 2: Both spoons reach a similar temperature at the end in the soup, but metal conducts thermal energy into your hand much faster, so it feels hotter. Which student's explanation depends on how fast energy is transferred? (Student 2 / Both students / Neither student / Student 1) → Student 2Prompt: Read each viewpoint and underline its key claim.

• 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 6 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 new observation contradicts a well-tested theory. What usually happens? (The theory is never changed / Scientists check the observation, then improve or replace the theory if it holds up / The observation is always thrown away / Science stops) → Scientists check the observation, then improve or replace the theory if it holds upPrompt: Science changes when evidence changes.
2. Two students explain why a metal spoon in hot soup feels hotter than a wooden spoon in the same soup. Student 1: The metal spoon is at a higher temperature than the wooden spoon. Student 2: Both spoons reach a similar temperature at the end in the soup, but metal conducts thermal energy into your hand much faster, so it feels hotter. A thermometer shows the tips of both spoons in the soup at the same temperature. This result supports… (Student 1 / neither student / Student 2 / both students equally) → Student 2Prompt: Read each viewpoint and underline its key claim.

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