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Science lesson plan · 3rd grade (Year 4 in England) · 60 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 · 6 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 how far a paper plane flew? (weighing scales / a measuring jug or cylinder / a stopwatch or timer / a ruler or tape measure) → a ruler or tape measurePrompt: Is it a length, a temperature, a mass, a time or an amount of liquid?
  2. What could you measure with a measuring jug or cylinder? (the width of a leaf / how long a toy car takes to roll down a ramp / how long a candle burns / how much juice is in a carton) → how much juice is in a cartonPrompt: 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 · 6 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 · 12 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 · 12 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. Isla tests which ball bounces highest. She drops one ball from 1 m and another from 2 m. What is wrong? (The drop height should be the same / Nothing, it is fair / She should use only one ball / She should not measure the bounce) → The drop height should be the samePrompt: What is she trying to compare?
  2. Which question can be answered with a fair test? (Does a heavier parachute fall faster? / Is a rainbow beautiful? / What is your favourite plant? / Who is the best scientist?) → Does a heavier parachute fall faster?Prompt: A fair test changes one thing and measures another.

You do: independent practice · 17 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 8 questions are on the student sheet below, with answers in the key.

Exit ticket · 7 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Which question can be answered with a fair test? (Does a heavier parachute fall faster? / What is your favourite plant? / Who is the best scientist? / Is a rainbow beautiful?) → Does a heavier parachute fall faster?Prompt: A fair test changes one thing and measures another.
  2. Leo tests which paper towel soaks up the most water. What should he change? (the amount of water / the time he waits / the type of paper towel / the size of the towel) → the type of paper towelPrompt: In a fair test you change only one thing: the thing you are testing.

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/ 8

  1. Question 1

    Leo tests which paper towel soaks up the most water. What should he change?

    • A. the size of the towel
    • B. the type of paper towel
    • C. the time he waits
    • D. the amount of water
  2. Question 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?

    • A. the note he hears
    • B. how tight and thick the strings are
    • C. nothing else matters
    • D. the length of the strings
  3. Question 3

    Fair tests: which statement is true?

    • A. You should change as many things as possible.
    • B. In a fair test you change only one thing.
    • C. One try is always enough.
    • D. If a result surprises you, you should hide it.
  4. Question 4

    Why is it a good idea to repeat a test several times?

    • A. To change the answer
    • B. To check the results are reliable
    • C. Because the first try never counts
    • D. To make the test unfair
  5. Question 5

    Which question can be answered with a fair test?

    • A. Does a heavier parachute fall faster?
    • B. Is a rainbow beautiful?
    • C. What is your favourite plant?
    • D. Who is the best scientist?
  6. Question 6

    Isla tests which ball bounces highest. She drops one ball from 1 m and another from 2 m. What is wrong?

    • A. Nothing, it is fair
    • B. She should not measure the bounce
    • C. The drop height should be the same
    • D. She should use only one ball
  7. Question 7

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

    • A. nothing
    • B. how far the car rolls
    • C. the type of surface
    • D. the height of the ramp
  8. Question 8

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

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

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Answer key: Planning a fair test

  1. 1. B. the type of paper towel

  2. 2. B. how tight and thick the strings are

  3. 3. B. In a fair test you change only one thing.

  4. 4. B. To check the results are reliable

  5. 5. A. Does a heavier parachute fall faster?

  6. 6. C. The drop height should be the same

  7. 7. D. the height of the ramp

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