• Quick retrieval from earlier learning (Planning a fair test). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Leo tests which paper towel soaks up the most water. What should he change? (the amount of water / the time he waits / the size of the towel / the type of paper towel) → the type of paper towelPrompt: In a fair test you change only one thing: the thing you are testing.
2. Omar tests how the length of a guitar string changes its note. He uses strings of different lengths. What else should stay the same? (the length of the strings / nothing else matters / how tight and thick the strings are / the note he hears) → how tight and thick the strings arePrompt: Tightness and thickness also change the note.
3. Fair tests: which statement is true? (You should change as many things as possible. / You should keep everything else the same. / One try is always enough. / A fair test means everyone gets a turn.) → You should keep everything else the same.Prompt: Think about what makes a test fair.

• Show a simple experiment with one thing changed and ask what makes it a fair test.
• Share the objective: Independent, dependent and control variables. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Investigation: Does the surface area of a puddle affect how fast it evaporates? Which is the independent variable (the one you change)?
• Step 1: Change: surface area of the water. Measure: time for the water to evaporate. Keep the same: volume of water, temperature of the room.
• Step 2: So the answer is: surface area of the water
• Answer: surface area of the water
• 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. Investigation: How does the mass of a pendulum bob affect the time of one swing? Which is the independent variable (the one you change)? (mass of the bob / time for one swing / surface area of the water / starting angle) → mass of the bobPrompt: Independent variable: the one you change. Dependent variable: the one you measure.
2. Investigation: How does the mass of a pendulum bob affect the time of one swing? Which is the dependent variable (the one you measure)? (mass of the bob / time for one swing / starting angle / height of the cress) → time for one swingPrompt: Independent variable: the one you change. Dependent variable: the one you measure.

• 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. Investigation: Does the size of a parachute affect how long it takes to fall? Which is the independent variable (the one you change)? (time to fall / mass of the bob / drop height / size of the parachute) → size of the parachutePrompt: Independent variable: the one you change. Dependent variable: the one you measure.
2. Investigation: How does the height of a ramp affect how far a toy car travels? Which is a control variable (one you keep the same)? (the same floor surface / height of the cress / distance the car travels / height of the ramp) → the same floor surfacePrompt: Independent variable: the one you change. Dependent variable: the one you measure.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-5.