• 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 time he waits / the type of paper towel / the amount of water / the size of the 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 note he hears / nothing else matters / the length of the strings / how tight and thick the strings are) → how tight and thick the strings arePrompt: Tightness and thickness also change the note.
3. Fair tests: which statement is true? (One try is always enough. / A fair test means everyone gets a turn. / A prediction says what you think will happen. / You should change as many things as possible.) → A prediction says what you think will happen.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 amount of light affect the growth of cress? Which is the independent variable (the one you change)? (height of the cress / amount of light / water temperature / type of soil) → amount of lightPrompt: Independent variable: the one you change. Dependent variable: the one you measure.
2. Investigation: How does exercise affect heart rate? Which is the dependent variable (the one you measure)? (minutes of exercise / time for one swing / heart rate (beats per minute) / the same person) → heart rate (beats per minute)Prompt: 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: How does exercise affect heart rate? Which is a control variable (one you keep the same)? (minutes of exercise / heart rate (beats per minute) / type of exercise / time to fall) → type of exercisePrompt: Independent variable: the one you change. Dependent variable: the one you measure.
2. Investigation: Does the size of a parachute affect how long it takes to fall? Which is the independent variable (the one you change)? (size of the parachute / mass hanging from it / height of the ramp / time to fall) → size of the parachutePrompt: 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.