The Effect
A clear glass filled with water and a coin are shown openly.
The coin is tapped against the solid base of the glass and then slowly pressed against it.
With a final push, the coin appears to pass through the glass and becomes visible inside the water.
What You’ll Need
🥛 Clear Glass
Choose a glass with a smooth base and clear sides.
🪙 Two Matching Coins
Both coins should be the same size, colour and design.
💧 Water
Fill the glass enough to help conceal the duplicate coin.
Secret Preparation
Before the performance, place one of the matching coins inside the glass.
Stand the coin upright against the inner wall near the bottom of the glass.
When you hold the glass, position your fingers in front of the hidden coin so the audience cannot see it.
Check the setup from the spectators’ expected viewing angle before beginning.
Watch the Tutorial
Watch the performance and explanation once before practising the handling yourself.
Step-by-Step Method
Step 1 — Display the Glass
Pick up the glass with your fingers covering the hidden coin. Tilt it only enough to show the water without exposing the secret preparation.
Step 2 — Show the Coin
Display the second coin clearly in your free hand and tap it against the base of the glass to prove the glass is solid.
Step 3 — Begin the Penetration
Press the visible coin slowly against the glass as though you are pushing it through the base.
Step 4 — Conceal the Visible Coin
Let the coin slide downward through your fingertips and retain it secretly in Finger Palm.
Step 5 — Reveal the Duplicate
Rotate the glass slightly so the hidden coin becomes visible inside the water at the exact moment the first coin disappears.
Step 6 — Pause for the Reaction
Hold the glass still and let the audience register that a coin is now apparently inside.
How the Secret Works
The audience assumes the coin that was pressed against the glass is the same coin they later see inside the water.
In reality, the visible coin is retained secretly in your hand while the matching coin already inside the glass is revealed.
Careful timing connects the disappearance outside the glass with the appearance inside it, creating the illusion of penetration.
Science Behind the Magic
💡 Why the Hidden Coin Is Hard to See
Light changes direction as it passes between air, glass and water. This effect, called refraction, can distort the appearance of objects inside the glass and helps disguise the duplicate coin when combined with your fingers and the correct viewing angle.
Performance Tips
Keep the glass upright and avoid moving it more than necessary before the reveal.
Press the visible coin against the same side of the glass where the duplicate is positioned.
Make the apparent penetration slow and deliberate. The effect becomes stronger when spectators believe they can see the whole process.
Rotate the glass only enough to reveal the hidden coin. A large or sudden turn can look suspicious.
🎩 Magic Tip
Do not rush the reveal. Pause for a fraction of a second after the visible coin disappears, then allow the duplicate coin to come into view.
Practice Exercise
Set up the duplicate coin and view the glass from several angles in a mirror.
Practise lifting, displaying and rotating the glass without exposing the hidden coin.
Rehearse sliding the visible coin into Finger Palm until the action looks like a smooth continuation of the pushing motion.
Finally, practise the concealment and reveal together so both events appear to happen at the same moment.
Common Mistakes
Do not use coins that differ in colour, size or wear.
Avoid tilting the glass before the reveal.
Do not rotate the glass too quickly or too far.
Keep the hand concealing the visible coin relaxed after the penetration.
Make sure the duplicate coin is stable and will not slide or fall unexpectedly.