How to do the pendulum trick: the swing that reads your mind

In the pendulum trick, a volunteer holds a ring on a thread over a drawn cross, thinks about one line, and the pendulum starts to swing along it. Nothing is gimmicked. It runs on the ideomotor effect, tiny movements people make without knowing it, which makes it an honest and surprising demonstration of mentalism.

What does the audience see?

A volunteer holds a homemade pendulum perfectly still over a sheet of paper. You ask them to concentrate on the line that runs away from them. Slowly, the pendulum begins to swing back and forth along that line. Then you ask them to think about the other line, and the swing changes direction. Finally, they think about the circle, and it starts to go round.

The best part is that the volunteer is the one holding it. They know they aren’t moving it on purpose, and that is what makes the moment feel strange.

What do you need?

• A pendulum. A ring, a button, a key or a pendant tied to a piece of thread about as long as your forearm.
• A target. A sheet of paper with a large cross and a circle drawn over it.
• A volunteer who is happy to join in. The more curious they are, the better.

How do you do the pendulum trick?

1. Set the scene. Explain that you want to test how strongly their thoughts affect their body. Frame it as an experiment, not a claim of psychic power.
2. Get the grip right. Have them hold the end of the thread between thumb and first finger, with the weight hanging a few centimetres above the centre of the cross. Ask them to keep their hand as still as they can.
3. Give one clear thought. Ask them to watch the pendulum closely and think only about the line that runs away from them, imagining the weight swinging along it. Keep your voice calm and repeat the idea.
4. Wait. It can take a little while. As soon as you see the swing start, describe it out loud: “There. It’s starting to follow the line.” That expectation tends to make the movement grow.
5. Change direction. Ask them to switch their thoughts to the line that goes left to right. Then try the circle.
6. Finish well. Thank them and tell them it was their own mind at work. That is the truth, and it’s more interesting than a mystery prop.

Why does the pendulum move?

Based on our research, one of the earliest explanations we’ve found is by the French chemist Michel Eugène Chevreul, who set out his conclusions in an open letter to André-Marie Ampère in 1833. He decided the swings came from small muscle movements in the holder that the holder did not notice. In 1854 he published a book, De la baguette divinatoire, du pendule dit explorateur et des tables tournantes, which applied the same explanation to the divining rod, the pendulum and table-turning.

In 1852 William Carpenter coined the term “ideo-motor” for movements produced by an idea rather than a decision. Michael Faraday also tested table-turning and came to a similar conclusion. Ray Hyman later summed it up: “honest, intelligent people can unconsciously engage in muscular activity that is consistent with their expectations.”

The same effect is used to explain dowsing rods and talking boards. Magicians also rely on unconscious cues in some “mind-reading” acts.

What are the common mistakes?

• Claiming real powers. Present it as a demonstration of the mind, not a supernatural event. It lands better with curious adults that way, and it’s honest.
• Rushing it. The swing builds slowly. Silence and patience help more than extra instructions.
• A heavy or long pendulum. Start with a light weight on a forearm’s length of thread.
• Letting them look away. Ask the volunteer to keep watching the pendulum the whole time.

What helps you take it further?

• PITATA Pendulum Sharpie. A pendulum tool for mentalism routines that looks like a real mini Sharpie and doubles as a working pen. It comes with a tutorial of 15 routines, including mind reading, predictions and a chair test, plus a custom tarot deck.
• The Pendulum by Tony Anverdi. A pendulum that sways with no visible cause to reveal a chosen card or thought. It is an add-on: you must own Anverdi’s Spirit Bell or Spirit Bell Deluxe Set to use it.
• Modern Magic by Professor Hoffmann, free from our public-domain library. Its appendix covers second sight, spiritualism and parlour magic, including mediums and their tests.

New to this side of magic? Start with our beginner’s guide to mentalism and our guide to choosing your first mentalism trick.

Frequently asked questions