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Science lesson plan · 3rd grade (Year 4 in England) · 30 minutes

Planning a fair test

Working scientifically

CCSS NGSS.SEP 3CCSS NGSS.3-PS2-1England: KS2 Y3–Y4 Working scientifically

Objective and success criteria

Students will: Planning a fair test.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Choosing a measuring tool

Leads to: Independent, dependent and control variables

Materials: Simple equipment for a fair test, Results table template, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 4 min

  • Quick retrieval from earlier learning (Choosing a measuring tool). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Which tool would you use to measure the mass of a pumpkin? (a stopwatch or timer / weighing scales / a measuring jug or cylinder / a ruler or tape measure) → weighing scalesPrompt: Is it a length, a temperature, a mass, a time or an amount of liquid?
  2. What could you measure with a thermometer? (how long a candle burns / the temperature outside / how heavy an apple is / how long a toy car takes to roll down a ramp) → the temperature outsidePrompt: What does this tool measure: length, temperature, mass, time or volume?
  3. Which tool would show that the water in a bowl is getting colder? (a measuring jug / a thermometer / a magnifying glass / a ruler) → a thermometerPrompt: Colder means the temperature is going down.

Hook · 3 min

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

I do: model it · 7 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Leo tests which paper towel soaks up the most water. What should he change?
  • Step 1: He is testing types of paper towel, so that is the only thing he changes.
  • Step 2: So the answer is: the type of paper towel
  • Answer: the type of paper towel
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 6 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. Leo tests which paper towel soaks up the most water. What should he change? (the time he waits / the size of the towel / the amount of water / 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. Which question can be answered with a fair test? (Is a rainbow beautiful? / What is your favourite plant? / Who is the best scientist? / Does a heavier parachute fall faster?) → Does a heavier parachute fall faster?Prompt: A fair test changes one thing and measures another.

You do: independent practice · 7 min

  • 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.

Exit ticket · 3 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Priya tests which surface a toy car rolls furthest on. What must she keep the same? (the type of surface / how far the car rolls / nothing / the height of the ramp) → the height of the rampPrompt: Only the surface should change.
  2. Aisha measures how fast sugar dissolves in water at different temperatures. What does she measure? (the temperature of the water / the type of cup / the time for the sugar to dissolve / the colour of the sugar) → the time for the sugar to dissolvePrompt: She changes the temperature. What does she then look at?

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Choosing a measuring tool.
  • Use concrete materials: simple equipment for a fair test.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Move on to: Independent, dependent and control variables.
  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-3.

Free lesson plan from eurekami.com/lesson-plan-builder

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Planning a fair test

Name

Date

Score/ 6

  1. Question 1

    Fair tests: which statement is true?

    • A. A prediction says what you think will happen.
    • B. A fair test means everyone gets a turn.
    • C. If a result surprises you, you should hide it.
    • D. You should change as many things as possible.
  2. Question 2

    Ben tests whether salt water or tap water freezes faster. Which must he keep the same?

    • A. the type of water
    • B. whether the water has salt
    • C. the volume of water in each cup
    • D. the time each one takes to freeze
  3. Question 3

    Priya tests which surface a toy car rolls furthest on. What must she keep the same?

    • A. nothing
    • B. the type of surface
    • C. the height of the ramp
    • D. how far the car rolls
  4. Question 4

    Which question can be answered with a fair test?

    • A. What is your favourite plant?
    • B. Is a rainbow beautiful?
    • C. Who is the best scientist?
    • D. Does a heavier parachute fall faster?
  5. Question 5

    Mateo wants to know if plants grow better with more light. Which plan is fair?

    • A. Same plant type, same water, different amounts of light
    • B. Same light for every plant
    • C. More water for the plant in the light
    • D. Different plants, different water, different light
  6. Question 6

    Omar tests how the length of a guitar string changes its note. He uses strings of different lengths. What else should stay the same?

    • A. how tight and thick the strings are
    • B. the note he hears
    • C. the length of the strings
    • D. nothing else matters

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Answer key: Planning a fair test

  1. 1. A. A prediction says what you think will happen.

  2. 2. C. the volume of water in each cup

  3. 3. C. the height of the ramp

  4. 4. D. Does a heavier parachute fall faster?

  5. 5. A. Same plant type, same water, different amounts of light

  6. 6. A. how tight and thick the strings are