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3rd grade · Science · Unit 8 of 8

Magnet Inventions

Use magnets to solve problems, then test your design.

What your child practices

Practices using what magnets do to solve simple design problems, such as a latch or a sorter, by setting criteria and constraints and running fair tests that change one thing at a time.

Alaska content standards learning standard: 3-PS2-4; 3-5-ETS1-1; 3-5-ETS1-3 · solving design problems with magnets, setting criteria and constraints, and running fair tests

How we explain it

Children can open this short lesson before they practice.

  1. Magnets stick to iron and steel, and push or pull without touching.
  2. Design rules: criteria say what it must do, constraints say what limits you.
  3. A fair test changes only one thing at a time.

Example: Which could pick up spilled paper clips fast? Paper clips are steel. A magnet pulls steel. Answer: a magnet on a stick

Magnet Inventions in Alaska

In the Alaska content standards, this is unit 8 of 8 in 3rd grade Science, after Weather Hazards & Solutions.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Alaska Department of Education and Early Development

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A magnet sticks to…

    • glass
    • wood
    • plastic
    • iron and steel

  2. Question 2

    Which design uses magnets to keep a note on a fridge?

    • A rubber band
    • A magnet on the note
    • Tape on the floor
    • A wet sponge

  3. Question 3

    Why do engineers test a design many times?

    • To skip planning
    • To make it pretty
    • To waste magnets
    • To find where it fails

  4. Question 4

    In engineering, constraints are…

    • the winner
    • what the design must do
    • limits like time, cost or materials
    • a kind of force

  5. Question 5

    A magnet can sort steel cans from…

    • steel spoons
    • steel cans
    • aluminum cans
    • iron nails

  6. Question 6

    Two latch designs both hold the door. One costs less. If cost is a constraint, choose…

    • the one that costs less
    • the one that costs more
    • neither
    • a third one at random

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