All physicsfun toys

Jack in the Box Puzzle

Order this amazing puzzle here:

From Craighill & Art of Play: Order Now: Jack in the Box

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Jack in the Box Puzzle: eight solid aluminum pieces form a textured cube when carefully stacked- yet the same eight pieces can also be packed around a six pronged “jack” to form a second smooth silver cube that is barely larger that the first. Similar to the 2D Matsuyama’s paradox puzzle, a small square is centered on each face of the cube in the second solution. Some stages of assembly shown here under rotation to emphasize the beautiful symmetries in the design and avoid spoilers to the challenge. Created by Rod Bogart and engineered into existence by the talented folks at @craighillcompany, and I send a hearty thank you to my friends at @artofplay for sending me this unique and special puzzle. 

The Magic Octagon Coin

Get this new amazing coin here:

From Shire Post Mint: BUY NOW: Magic Octagon Coin

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“Magic Octagon” Challenge: introducing a beautiful copper coin version of this puzzle of successive rotations. Which way will the light arrow point after left and right rotations of the dark arrow? No trickery here- just the math of geometry, symmetry, rotations, and reflections and how our intuitions often fail us upon first attempts. Swipe twice for second challenge. In collaboration with my friends at @shirepostmint 

 

Square Dissection Puzzles

Get these and other well made disection puzzles here:

From Etsy: BUY NOW: Square Dissection Puzzles

These puzzles are expertly laser cut and sold by GamesEfce. I spray-painted the pieces of mine to better show the shapes and relationships for the video. 

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Square Dissection Puzzles: a square can be cut (dissected) into polygons and then reassembled into other regular polygons. Shown here: an equilateral triangle, a pentagon, and a hexagon. These are the record holders for smallest number of pieces needed: triangle (4 pieces by Henry Dudeney 1902), hexagon (5 pieces Paul Busschop 1870s) and pentagon (6 pieces Robert Brodie 1891). Fun fact- It is not known if any of these records are the smallest possible, no mathematical proofs yet exist on this question.


Sucrose Crystals

Edible and pretty sugar crystal clusters available here:

From Etsy: BUY NOW: Sucrose Crystal Clusters on a Stick

and here is a fun page describing how to grow large clear sugar crystals at home.

Note: this site contains affiliate links for which I may be compensated

Sucrose Crystals: so I recently found, in the back corner of my kitchen panty, this bottle of fancy maple syrup I bought a long time ago. Apparently the conditions in my pantry were just right to allow the sugar to form these large prismatic clear crystals. Sucrose is a complex molecule (C12H22O11) but forms crystals of elongated polyhedra often with irregular hexagonal forms as seen here. I soaked the label off this bottle to better view the crystals- and I put it back in the cupboard it to see if the crystals will grow further- accidental kitchen physics experiment in progress! 

Pickagram Puzzle

Get this well made puzzle here:

From Art of Play: BUY NOW: PIckagram Puzzle

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Pickagram: an innovative update on the classic Tangram puzzle- magnets added! With pieces that cling together with a satisfying snap, the 2D puzzle formations become 3D abstract sculptures that can stand on their own. From the mind of designer and architect Gilryong Song, with inspiration from the golden ratio in its proportions and angles.


Floating Eye Toys

Look for these anumal pens in airports gift shops (can't find them online).
Gliding eyes are still available here:
From Amazon: BUY NOW: Gliding Eye Toy

Note: this site contains affiliate links for which I may be compensated

Floating Eyes: low center of mass spheres suspended within a liquid filled clear acrylic sphere- the inside”eyeball” maintains its eerie orientation always pointing up as the outer shell rotates. I found these animal pens at airport gift shops and notice the eyes are the same as the spooky gliding eye toys from a few years back. Fun physics of Achimedes principle and constructing a low center of mass.

Oil Drop Timer

Available here: 
From Amazon: BUY NOW Drop Timer 

Note: this site contains affiliate links for which I may be compensated

Oil Drop Timer: immiscible liquids (typically, colored oils in kerosine) in two connected containers with interesting semi-translucent white and opaque black oils in this variation on the bubble timer theme. The oil in each container falls through a small drop forming hole in between clear walls of acrylic- note how surface tension forms the drops into nearly perfect circles and regulates the size of the drop formation. In addition the drops fall at terminal velocity with smaller drops falling faster than larger ones. One of my favorite inexpensive physics toys. 

Sphericon Frame Roller

Get one here:

From Etsy: BUY NOW: Quantum Sphericon

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Sphericon Frame Roller: beautiful 3D printed version of a developable roller (an object that rolls where every point on the roller’s surface comes into contact with the plane upon which it rolls). The sphericon (based on a square) rolls in a straight line with a peculiar wobble motion and was discovered in 1980 by David Hirsch and is but one of a family of such rollers called polycons. 


Coins of Constant Width

These triangle coins are often available on eBay.
From eBay: Search NOW: Bermuda Triangle Coin

Click to see more: shapes of constant width and here for 3D shapes of constant width (orbiforms)

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Coins of Constant Width: this post celebrates pi day with coins in the form of Reuleaux polygons- shapes for which their perimeter/diameter = π, just like the circle! The special convex shapes of the Reuleaux triangle (Bermuda 1 dollar) and Reuleaux heptagon (UK 50 pence) will roll, because like a circle they have the same diameter from one side to the other, no matter their orientation. To demonstrate this property note how two straightedge rulers remain parallel as the coins rotate between them, just as one would expect circles to behave. Bermuda triangle (ha!) coins are the only coins produced in the shape of the Reuleaux triangle, issued in 1997-98 and featured Elizabeth II on the front and shipwrecks on the back.

2-Mirror Kaleidoscope 

Lief Colson's store is now Colorfulscopes on Etsy with many designs to choose from- all with precision aligned high quality front surface mirrors: 
From Etsy store Colorfulcopes : BUY NOW Precision Teleidoscopes 

Amazing next-level fine art kaleidoscopes avaibable here:
From Etsy: BUY NOW: Fine Art Kaleidoscopes

Note: this site contains affiliate links for which I may be compensated

2-Mirror Kaleidoscope: two mirrors, precisely aligned at an 18 degree angle, produce a 10 fold symmetry, where bits of colored plastic morph into stars, pentagons, and flowers as this unique kaleidoscope is turned back and forth. An elegant anodized blue metallic cylinder encapsulates a universe of possible images within. Another amazing kaleidoscope in my expanding collection, made by artist Lief Colson.

Flippe Puzzle Ball

Get this puzzle ball here:

From Etsy: BUY NOW: Flippe Puzzle Ball

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Flippe Ball Puzzle: this ball is a puzzle that explodes and flies apart when spun. The puzzle is made of three identical pieces and a ball bearing which mysteriously locks the pieces together only to release them after a period of spinning. The main challenge is to fully explain why this spontaneous disassembly occurs. A slow motion “instant replay” of it coming apart reveals how conservation of momentum has each of the three equal mass pieces fly away on equally spaced trajectories (120°) with the ball bearing remaining stationary at the center and falling straight down. A product of puzzle master George Bell. 


Spiderman Hologram

This vintage hologram still available here:
From Amazon: BUY NOW: Spiderman Hologram

Similar vintage holograms are currently available on Etsy in limited quantities: 
From Etsy: BUY NOW Photopolymer True Hologram

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Spiderman Hologram: amazing 3D depth in this vintage hologram from 1995 encoded on thin red plastic and sold as a sticker- the image only appears if a light source is placed above the top of the composition at the correct angle. Unlike photographs, holograms are recordings of the interference pattern of light waves, and this encoded information is stored in a layer thinner than a sheet of paper. 

Zoetrope Vinyl

Get this amazing vinyl here:

From Amazon: BUY NOW: Dune Rats Zoetrope Vinyl

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Zoetrope Vinyl: slight adjustment of the iPhone camera frame rate reveals an amazing animation built into this multicolored vinyl release “Hurry Up and Wait” by the Dune Rats. The art is designed to interact with the video process, similar to the animation effect of a flip book, but in a repeating cycle like that of the phenakistiscope, the 1833 invention that started moving media animation that lead to the development of movies and video. 

 

Earth Mass Black Hole with Space Warping Display Stand

Precision machined tungsten alloy spheres available here:

From STEMCell Science: BUY NOW: Tungsten Black Hole Replica

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Earth Mass Black Hole: this sphere of tungsten alloy has a diameter of 17.7mm, a precision representation of the size of the event horizon of a black hole with a mass equal to that of the Earth! If the entire mass of the earth could somehow be compressed to the size of this sphere, it would indeed collapse to a black hole with an event horizon defined by a Schwarzschild radius of 8.87mm. For comparison a black hole with the mass of the sun would be 6km across. This black hole replica is made of one of the densest materials available, a tungsten alloy with ρ=18.5 g/cm³ which produces a strange sensation when you hold it, with a weight of twice that of a ball bearing of equal size.


Thermochromic Eclipse Postage Stamps

Available from the US Post Office and here: 
From Amazon: BUY NOW Thermochromic Eclipse Stamps 

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Thermocromic Eclipse Postage Stamps: In commemoration of the 2017 total solar eclipse the US Post Office released their first ever stamp featuring thermocromic ink. The first physics toy stamp! Thermotropic liquid crystals go from opaque to transparent during a phase change from a crystal to liquid state. Here the warmth of the hand reveals the face of the moon in front of the solar corona. Almost seven years later another total eclipse will take place across part of the US on April 8- I’ll be in San Antonio for the event! 

Magnetic Influence on Aluminum

For this demonstration stronger magnets work best:
From Amazon: BUY NOW: Neodymium Magnets

Here is a good small turntable with bearings: 
From Amazon: BUY NOW: Spinning Base

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Magnetic Influence on Aluminum: physics puzzler- spin a magnet under a beer can suspended by a thread, and the can will turn. Why? Aluminum is not ferromagnetic, and as shown, magnets are not attracted to the can.  So how does a spinning magnet influence the can to spin? 

 

Answer: the can spins due to eddy currents induced in the conducting aluminum due to the moving magnetic fields underneath. The eddy currents make the can into a temporary electromagnet that then interacts with the magnets below according to the famous law by Lenz.

Eclipse Diamagnatic Sculpture

Click here to visit this amazing Etsy shop Element83 
Get a magnetic levitation sculpture here: 
From Etsy: BUY NOW Diamagnetic Levitation Sculptures 

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Eclipse diamagnetic levitation sculpture. Cast from diamagnetic Bismuth, a golden spherical neodymium magnet levitates trapped in a tunnel within the metal. Diamagnetic substances only have magnetic fields of their own when placed in an external magnetic field from another source- here the sphere magnet supplies the field. Diamagnetic fields are pretty weak though so a powerful cube neodymium magnet sits above the tunnel and is adjusted to help lift the sphere magnet against gravity. Trapped in equilibrium by these fields, any other magnet brought near will change the balance.