FeaturedBeginner
Kids Magic10 min
The Detachable Thumb
Pull the top half of your thumb clean off, slide it back on, and wiggle it to prove it survived.
EasyNo materials
Learn this trickAnimated demonstration
Kids Magic
The Color-Detecting Crayon
You turn your back, a child places any crayon from the box into your waiting hands, and moments later you announce the colour. It works with any crayon, any number of times, and the whole method is a fingernail. This is the perfect first 'real' trick for performing to children, because the magic happens entirely inside their imagination.
EasyHousehold objects
- Learning time
- 10 minutes
- Practice time
- ~20 minutes
- Recommended age
- 7+
- Setting
- Seated or standing with a small group of children directly in front of you.
Lesson overview
What the audience sees
You hold your hands behind your back and a child drops in any crayon they choose. You concentrate, press your fingertips to your forehead, and name the colour exactly. The crayon comes out and it is right — and you can do it again with a different one.
What the magician does
With the crayon hidden behind you, you dig a thumbnail into the wax and scrape a small amount under the nail. Bringing your hand forward to your forehead gives you a perfectly natural half-second in which to glance at the colour under your nail.
Why it works
Children are searching for mirrors, peeking, and helpful grown-ups. Nobody suspects a fingernail, and the reveal happens during a gesture — hand to forehead — that looks like the very definition of concentrating.
You'll practice
- Scrape a readable amount of wax under the nail quietly
- Time the glance inside a natural gesture
- Reveal the colour with dramatic pacing rather than a flat answer
- Reset and clean up between repeats
Materials
Household objects
Substitutes: Soft wax crayons are ideal. Chalk pastels or soft coloured pencils work too, though coloured pencils give up much less colour.
Before you begin
Test your crayons
Scrape each colour under your thumbnail once at home. Some pale colours barely show — decide in advance which you will quietly avoid.
Check your nails
You need a little length on one thumbnail. Trimmed-to-the-skin nails cannot pick up enough wax to read.
Have a tissue in your pocket
You will want to wipe the nail clean between performances, and a tissue makes that a two-second job.
Environment: Perform with the children in front of you and a wall or sofa behind you. Anyone standing behind you can see everything, and children move around constantly. A mirror — or your phone camera propped up — shows you exactly what your audience will see.
Step-by-step lesson
Step 1 of 80%
1. Set the scene
Show the box of crayons and tip them out so everyone can see there is nothing special about them. Explain that your fingers have learned to feel colours — warm colours feel warm, cold colours feel cold. Children accept a rule like that instantly and it gives the trick a story.
Practice tip: Let a child hold the box. Handing over the props at the start makes the ending far stronger.
The secret is sealed
Magicians earn secrets by intending to use them. Reveal it when you're ready to learn — and keep it to yourself afterward.
Performance script
A sample script to adapt — make it your own, and never rush the pauses.
- (Tip out the crayons.) "Ordinary crayons. Boring crayons. But my fingers went to a special school."
- (Turning around, hands out behind.) "Pick any one. Don't tell me. Don't even think it too loudly, I'm sensitive."
- (Hand to forehead.) "Ooh. That's cold. That's a cold colour... there's water in it... maybe sky..."
- "Blue. It's blue — and not just any blue, that's the good blue."
- (Show empty hands.) "Shall we do it once more? Somebody pick a really hard one."
Performance tips
- Keep the children in front of you at all times and back yourself against a wall or sofa.
- Turn your head firmly away while the crayon is chosen. Visible fairness at the start buys enormous credit at the end.
- Take one glance, never two. A second look at your nail is the only real exposure in the routine.
- Stretch out the reveal — children love shouting guesses, and their noise is part of the show.
- Stop after three rounds, with your hands clean and empty on the last one.
Common mistakes
Scraping so little wax that the colour under the nail is unreadable.
Fix: Press the nail in firmly and drag it a full centimetre along the side of the crayon. Practise until one scrape is always enough.
Looking at the thumbnail twice, or staring at it for a full second.
Fix: Take one half-second glance while the hand is travelling to your forehead, then close your eyes.
Forgetting to clean the nail before repeating, and reading a muddy mixed colour.
Fix: Wipe with a tissue or against your pocket lining between every round, disguised as a natural gesture.
Performing with children wandering around behind you.
Fix: Put your back to a wall and ask everyone to sit in front of you before you start.
Announcing the colour flatly the instant you know it.
Fix: Narrow it down out loud over ten seconds, including one wrong guess, before you commit.
Practice checklist
0/6 doneSaved on this device only — no account needed.
Related tricks
Beginner
Everyday Object Magic5 min
The Magnetic Pencil
A pencil sticks to your open palm as if magnetized — then falls on your command.
EasyHousehold objects
Learn this trickEveryday Object Magic20 min
The Vanishing Salt Shaker
A salt shaker is covered with a napkin, pushed through the solid table, and gone — leaving an empty paper shell.
IntermediateHousehold objectsPaper
Learn this trickFeaturedBeginner
Mind Reading5 min
The Mind-Reading Number
A spectator thinks of any number, does secret math in their head — and you reveal their final thought.
EasyNo materials
Learn this trickWant to go further with kids magic? Magicians point beginners at Self-Working Card Tricks by Karl Fulves.
All recommended booksPublished 2026-05-12 · Updated 2026-07-14 · Read our responsible magic guidelines