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Magic Meets Physics

Magic Meets Physics
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Make a magical floating-coin illusion using thread and a cup, then explore physics of balance, tension, and motion with safe hands-on experiments.

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Step-by-step guide to Magic Meets Physics

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The magic of physics - with Felix Flicker

What you need
Adult supervision required, clear tape, clear thread or fishing line, coin, pencil, plastic cup, ruler, scissors

Step 1

Lay out all your materials on a flat workspace so everything is easy to reach.

Step 2

Use the ruler to measure and mark about 30 cm of thread and cut it with scissors.

Step 3

Tie one end of the thread tightly around the coin with a small secure knot.

Step 4

Ask an adult to help you make a tiny hole near the top rim of the cup using the pencil point.

Step 5

Push the free end of the thread through the hole from inside to outside so the coin can hang inside the cup.

Step 6

Pull the thread so the coin hangs about 1–2 cm below the cup rim.

Step 7

Tape the outside end of the thread flat to the cup so the thread lies along the rim and is hidden.

Step 8

Cover the rim with your hand so the thread stays hidden and show the cup so the coin looks like it is floating.

Step 9

Gently pull the taped thread end to lift the coin and make it “float” higher.

Step 10

Move the tape point closer or farther to change the hanging length and repeat pulling to compare how the coin’s motion changes.

Step 11

Measure the coin height with the ruler for each test and write down the numbers to explore how length affects motion.

Step 12

Take a photo or short video of your floating-coin illusion and share your finished creation on DIY.org

Final steps

You're almost there! Complete all the steps, bring your creation to life, post it, and conquer the challenge!

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Help!?

I don’t have a coin, a 30 cm ruler, or a plastic cup—what can I use instead of those critical materials?

Use a metal washer, button, or flat stone instead of the coin, dental floss or fishing line instead of the thread, and a paper/yogurt cup or small plastic container in place of the cup while still measuring about 30 cm of thread with the ruler step.

The thread keeps showing or the coin keeps rubbing the cup—what should I check or redo?

Make the tiny hole carefully with the pencil point as instructed, re-tie the knot so the coin hangs 1–2 cm below the rim, press the tape firmly so the thread lies flat along the outside rim, and trim any excess free thread so it won’t rub the cup.

How can I adapt the steps for different age groups so the child is safe and still learns from the experiment?

For ages 3–5 have an adult pre-punch the hole and pre-cut the ~30 cm thread and help tie the coin while the child practices hiding the rim, for 6–9 let kids measure and thread with supervision, and for 10+ encourage experimenting with different coin weights and recording ruler measurements to explore how length affects motion.

What are simple ways to extend or personalize the floating-coin illusion after finishing the basic routine?

Decorate the cup and use colored thread or multiple coins to create cascading floats, move the tape point to compare hanging lengths as you measure with the ruler, and take slow-motion video to analyze and share your results on DIY.org as suggested.

Watch videos on how to perform Magic Meets Physics

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Magic Pot Trick Revealed! | Nope—Just Physics!

4 Videos

Facts about physics experiments for kids

⚖ Balance depends on the center of mass: move the support just a tiny bit and an object that seemed steady can topple instantly.

đŸȘ™ A modern U.S. penny weighs about 2.5 grams — light enough that a thin thread or fishing line can move or suspend it!

đŸŽ© Stage levitation tricks usually rely on clever tension, concealed threads, or hidden supports — not real supernatural forces.

đŸ§” Strong monofilament fishing line can hold dozens of kilograms even though it's nearly invisible at a distance—perfect for stealthy supports.

đŸ§Ș Tiny pulls create noticeable motion: small forces acting on light objects lead to quick accelerations (hello Newton's laws!).

How do you make the floating-coin illusion in the Magic Meets Physics activity?

To make the floating-coin illusion, tie a fine thread (clear fishing line) to a coin, run the thread through a small hole or under the rim of a plastic cup, and secure the other end to a fixed point (a chair back or tape to a table). Hold the cup so the thread is hidden and gently tilt or lift the cup while keeping the thread taut — the coin appears to float. After the trick, experiment with angle, tension and motion to observe balance, pendulum behavior, and friction.

What materials do I need for the Magic Meets Physics floating-coin experiment?

You'll need a coin or metal washer, clear fishing line or fine nylon thread, a plastic or paper cup (transparent helps), tape and scissors. Add a pin, straw or small hole punch to guide the thread, plus a ruler and flat tray or table space. Optional extras: small weights, markers to note balance points, and a magnifying glass. Keep small parts and sharp tools under adult supervision.

What ages is the Magic Meets Physics activity suitable for?

This activity suits children aged about 6–12. Ages 6–8 enjoy the magic with close adult help for threading, cutting and using pins. Ages 9–12 can set up experiments independently and explore tension, balance and motion. For preschoolers (3–5), offer a demonstration and guide simple observations — avoid giving them small parts. Always supervise younger children and adapt language and complexity to each child's motor skills and attention span.

What safety precautions should parents follow for Magic Meets Physics?

Safety first: supervise at all times. Use blunt needles or a straw instead of sharp pins; keep scissors and small parts away from young children. Avoid wrapping thread around a child's fingers, neck, or face to prevent choking or circulation risks. Work on a flat surface at eye level to prevent accidental pokes. Secure loose ends with tape to stop sudden jerks. If carrying out motion experiments, clear the area and wear safety glasses when testing fast swings.
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