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Invisible Forces Unit
Mystery 5 of 5
How can you unlock a door using a magnet?
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DISCUSS:

Can you think of any other properties of magnets that might be useful?

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DISCUSS:

What property of magnets makes them useful for making trains hover?

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DISCUSS:

How could we use this property of magnets (pushing and pulling at a distance) to create something useful? Do you have any ideas?

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Beginning Complete!

You've completed the Exploration & Activity!

If you have more time, view the assessment, reading, and extension activity in the optional extras.

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Optional Extras

Below are ideas for extending this topic beyond the activity and exploration you just completed.
  • End-of-Mystery Assessment and Answer Key
  • Readings: Gain a better understanding of how magnets work and try fun experiments along the way.
  • Video: This educational video introduces several strange and surprising ways that magnets are used.
  • Video Discussion: Find the magnets in this amazing Rube Goldberg machine.
  • Activities: Fun activities to get your students thinking more about magnets.
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Readings

These online books are free with registration as an educator on Epic!.

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Video Discussion

  • Watch this video of a chain reaction. How do the parts work together? Can you spot the magnets? How can you tell where they are?

  • Here's a tip: There are steel marbles and glass marbles. Look for places where the steel marbles do something unexpected because they're interacting with a magnet.

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Activities

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Overview
Grade 3rd
Topic Forces, Motion, & Magnets
Focus Magnets & Engineering
Print
Activity Prep

In this Mystery, students investigate magnetic attraction and repulsion. In the activity, Invent a Magnetic Lock, students apply their scientific ideas about magnets to create a useful product: a magnetic lock that can open a paper door. Students engage in the engineering design process to test and improve their designs.

Preview activity

Number of students:
Pencil
30 pencils
Scissors
30 pairs
Cardstock
30 sheets
Dot Stickers
Pieces of tape will also work. We prefer dot stickers because they are easier to distribute in a classroom.
Details
180 stickers
Index Cards (3x5)
60 cards
Paper Clips
30 clips
Paper Fasteners
30 fasteners
Post-Its (3")
30 post-its
Ring Magnets
30 magnets

OPTIONAL SUPPLIES

Clipboard
Used to help troubleshoot if paper walls keep falling down. You can also use a heavy book to help.
Details
30 clipboards
Prep Instructions

Sort Materials Into Two Piles

Each student will first make a paper door using cardstock, scissors, and a post-it note. Then, students will design a lock for their door using a magnet, paperclip, paper fastener, stickers, and index cards. You may want to sort your materials into two piles for easier distribution.

Be Prepared for Some Troubleshooting

In this activity, students are asked to create something new -- an essential part of the engineering process -- but one that may confuse or frustrate them. Below are some of the more common difficulties we found during our own testing, and the solutions we came up with.

  • Brads won’t puncture paper: Students may have trouble puncturing the paper with the brad. If this happens, use a sharp pencil to poke a small hole in the paper, then insert the brad.

  • Items won’t turn on the brad: The hole probably isn’t big enough. Twist the brad in a full circle a few times to enlarge the hole.

pointybeak

  • The magnet doesn’t make the lock move: Every lock will work differently, but it’s typically friction that causes this problem. If a piece of your lock is supposed to move, be sure it can move easily. If it’s attached too tightly, your magnet may not be able to move it.

  • Pieces keep getting stuck against one another:

    • If your lock keeps getting stuck, try rounding the edges of the moving parts. lock troubleshoot #1 lock troubleshoot #2
    • If the lock is getting stuck because a piece of paper is bending the wrong way, you can make the paper stiffer by folding it and adding stickers or paper clips to hold it together.

lock troubleshoot #3

  • Walls keep falling down: If you need help getting your wall to stay up, clip the 1-inch fold on the back to a clipboard, or slide it under the edge of a heavy book.

lock troubleshoot #4

Overview
Grade 3rd
Topic Forces, Motion, & Magnets
Focus Magnets & Engineering