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Science · Grade 3

Plan a Fair Comparison

Third graders learn to plan investigations like scientists: identify the one variable to change, the variables to keep the same and the result to measure. Using a ramp simulation with two variables (ramp height and floor surface), they spot unfair tests, collect repeated trials in a table, find the middle value and write a conclusion the data actually supports.

  • 3 lessons
  • About 85 minutes
  • Fair comparisons check: 9 questions
  • Ways to answer: choose an answer, highlight a text, type a number, place on a number line, put in order and sort into groups
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What learners will discover

  • Identify the variable to change, the variables to keep the same and the result to measure in an investigation.
  • Plan a fair comparison and explain why changing two variables at once makes a test unfair.
  • Record repeated trials in a table, find the middle value and state a conclusion supported by the data.

Lessons

  1. Variables: change one, keep the rest 4 steps2 practiceabout 25 min
  2. Fair or unfair? 6 steps3 practiceabout 28 min
  3. Repeat, record and conclude 7 steps3 practiceabout 32 min
  4. Fair comparisons check 9 questions at the end

Keep exploring

Games to practice with

  • Marble MountainLay straights, curves, drops and splitters to roll marbles down the mountain.
  • Bridge LabBuild a bridge from beams, brace it with triangles, and stay on budget.
  • Circuit Workshop 3DWire up batteries, bulbs and switches on a 3D workbench.

More 3rd grade science

Guide for grown-ups