Fun Mystery Unit Activities – Let Your Kids Think Like Detectives!

Mystery activities = fun! Let your kids think like detectives. They’ll love cracking codes, experimenting with invisible ink, fingerprinting, observation games, and more! At home or in the classroom, mystery activities add excitement.

Mystery Activities

Secret Codes

Kids love secret codes. These paper/pencil sheets let kids break codes then write their own. Click here for a free sample!

Mystery Activities - Secret Codes

Invisible Ink

In my classroom, we tried five different kinds of invisible ink. Those requiring heat didn’t work well. My little detectives recommend these three methods:

  • Method 1 – Stack two pieces of paper on the table. Write a message on the top paper, pressing firmly. Then remove the top sheet. To see what was written, lightly shade the bottom sheet with a pencil.

Mystery Activities - Invisible Ink 1

  • Method 2 – First, write on paper with a white crayon. Brush with watercolor paint to discover what was written.

Mystery Activities - Invisible Ink 2

  • Method 3 – Mix equal amounts of baking soda and water in a bowl. Next, write on paper with a Q-tip. Dry. Brush with grape or cranberry juice to discover what was written.

Mystery Activities - Invisible Ink 3


It’s as easy as loop, whorl, and arch! Kids feel like real detectives when they take fingerprints. You can use an ink pad or simple pencil lead.

Mystery Activities - Fingerprints

Tip: For clear fingerprints, use the pencil lead method. Then, instead of pressing directly onto paper, stick clear tape on the fingertip. Peel off and stick tape on paper.

Mystery Activities That Require Observation

How observant are your students? Hone their observation skills with classroom and online games.

  1. Move five objects in the classroom each day. How many can each child notice?
  2. Go to a place in the classroom where the kids can’t see you. Ask questions about your eye color, the clothing you’re wearing, etc.
  3. Arrange 30 items on a tray. Let the students look at it for 30 seconds. Then take the tray away. How many items can they remember?
  4. For some online fun, visit CIA Kids Zone. Take the Photo Analysis Challenge and play Concentration.

When kids are more observant, they’re better readers. Observation activities are fun – and well worth the time.

More Mystery Activities

To solve a mystery, detectives must think logically. Similarly, to understand a mystery story, kids must think logically. Using logic puzzles helps them develop deductive reasoning. To solve some puzzles online, try this site.

Mystery Activities - Logic Puzzles

Now you know how your kids can think like a detective. Read on to see how they can read like a detective and write like a detective.

For a complete mystery unit, visit my TpT store for more fun mystery activitiesmystery reading passages, and mystery writing activities.

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