Pin-Tumbler Lock
One of many amazing and accurate models made by Theodore Gray:
From MechanicalGifs.com: BUY NOW Pin-Tumbler Lock Acrylic Model Kit
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Pin-Tumbler Lock: simple and accurate model of how a basic lock works. The pins (orange/green) are held in place with springs and keep the tumbler from sliding and releasing the chain. The contour cut into the edge of the key must match the lengths of the green parts of the pins. When the key is inserted, the edges of the green pins line up allowing the tumbler to slide, unlocking the chain. In most locks the tumbler rotates instead of sliding, but the principle is the same. One of many “Transparently Obvious” models in the Mechanical Gifs series created by Theodore Gray.
Cartesian Diver
Get one here!
From Amazon: BUY NOW Cartesian Divers
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Cartesian Diver: increasing pressure on the water compresses the air bubble in the small plastic vial (here in the shape of an octopus' head) filling it further with water and making the diver sink. Pascal's principle states that any change in pressure on an enclosed fluid (such as squeezing the plastic bottle) is transmitted evenly to every part of the fluid- the physics of hydraulic brakes! The physics here is great- but the biology is questionable: it's not clear why an octopus would need mask and snorkel!
Surface Tension Bar Bet
Further details on the physics of surface tension:
Wikipedia: Surface Tension
The science writer Martin Gardner has published many books of physics tricks and simple but amazing science experiments like the one in this video. Highly recommended.
From Amazon: BUY NOW Martin Gardner's Science Magic: Tricks and Puzzles
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Thanks to Mark Setteducati for sending me this Eureka Cup, part of his Wow Science series of toys from the 1990s.
Surface Tension Bar Bet: How many marbles can be added to a full glass of water without spilling a drop? Surface tension allows a surprisingly large volume of water to rise above the rim of the glass without flowing over. This physics demonstration also works well with a shot glass and coins, and glassware types that are wider at the top enhance the dramatic effect. Many thanks to Mark Setteducati for sending me this version of his Eureka Cup.
Digital Sundial
Invented in 1994 and designed and built in Germany, the microlouver masks are precision engineered to give 10 minute accuracy to the digital sundial. Learn more about the inventors and how to buy a digital sundial for your specific latitude here:
From Digital Sundials International: Digital Sundial
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Digital Sundial: a complex array of thinly layered microlouvers allows the control of transmitted sunlight depending on angle. Time is read by looking at the reflection of the filter in the bottom mirror. 11:30 AM to 2:00 PM shown here in 15 seconds of time lapse- note the movement of the shadow cast by the sun as the Earth turns underneath during this 2.5 hour interval. Astonishing engineering.
Strandbeest Mini
Get one here! Make sure to get the Jr. Scientist version of this kit for best results.
From Amazon: BUY NOW Strandbeest Model Kit
Read about Theo Jansen and his novel leg linkage mechanism for the Strandbeests via these Wiki pages.
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Strandbeest Mini: A fully working model of artist Theo Jansen's Strandbeest kinetic sculpture which features Jansen's linkage- a unique leg mechanism which converts rotary motion of a crackshaft into smooth walking motion. Jansen's creations are usually a couple meters high and walk the beaches of the Netherlands powered by the wind. This version comes as a model kit that snaps together with no glue- a really fun project!
Planetary Gear Train
From Rail and Oak: the Esty shop of Logan Needham
From Etsy: BUY NOW Planetary Gear System
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Planetary Gear Train: with non-circular gears! This piece of kinetic art features a 6-sided Sun Gear, six 3-sided Planetary Gears, all held within the 12-sided space of the Annular Gear. The video captures three of the many interesting modes of these epicylic gear systems: 1) holding the sun gear fixed while rotating the annular gear allows the planetary gears to orbit, 2) pinning the planetary gears such that they can spin (but not orbit) allows the sun gear to go in the reverse direction of the annular gear, 3) holding one planetary gear fixed produces curious motion- note that although the other planetary gears move they do not spin about their axes! Situation 2) is how reverse gear is accomplished in the transmissions of many vehicles. Thanks to Logan Needham (@pillagethenburn) for the ingenuous display stand that allows full demonstration of this work of physics and engineering art.
RIZE Spinning Ferrofluid Display
Ferrofluid display cells available in a variety of colors:
From Amazon: BUY NOW RIZE Ferrofluid Interactive Scuplture
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RIZE Spinning Ferrofluid Display: by @mtrdesigns - a colloidal ferromagnetic liquid forms a spiked helix around the threads of a steel bolt in this kinetic sculpture. The bolt contains ferromagnetic iron which channels the field from the strong neodymium magnet in the base and focuses it into the spiral configuration. The curious spiking behavior results from the interplay between magnetic force and surface tension between the liquids.?Special thanks to Matt of MTR Designs studio for this beautiful interactive display.
Jacob’s Ladder Image Flip
Available from this shop in Spain:
From Punto Verna: Reproduction Jacob's Ladder
Classic versions of this toy available here:
Amazon: BUY NOW Jacob's Ladder Toys
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The same ribbon hinge mechanism is used to make the "magic" wallet click here
Jacob’s Ladder Image Flip: with a twist of the wrist this reproduction flips back and forth between an image of Queen Victoria and that of Prince Albert with a satisfying click-clack sound. The earliest description of the ribbon hinge mechanism that creates this kinetic illusion of cascading blocks comes from a magazine article in Scientific American in 1889.
Center of Mass Spinning Top
Available here
From DaWanda: Magneto Gyro by Kreisel
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Center of Mass Spinning Top: any 2D shape will spin nicely if spun about an axis through its center of mass. Careful placement of stem (held in place by neodymium magnets) allows the half disk of this acrylic protractor to spin evenly. If the placement is off by even a millimeter the top will not balance. Thanks to Tim Rowett for sending me this unusual top.
Colored Ferrofluid Display Cells
Available on Etsy: BUY NOW Motion Ferrofluid Sculpture
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Colored Ferrofluid Display Cells: spectacular metallic blue, gold, and black display cells by czferro - colloidal ferromagnetic liquids in a specially prepared water-alcohol suspension. Curious behavior results from the interplay between magnetic force and surface tension. The gold and blue coloring appears to be from a thin coating at the boundary between the ferrofluid and the suspension liquid. Still exploring the details of the coloring and the specific makeup of the clear suspension fluid - both trade secrets it seems.
Magswitch
The smallest Magswitch in this product line, yet it can lift 17 lbs! The Magjig 60:
From Amazon: BUY NOW Magswitch 60
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Magswitch: switchable permanent magnet- a twist of a knob turns on a magnetic field strong enough to lift this 5.2 kilogram (11 pound) chunk of railroad rail. Magnetic fields, when combined, can be either additive or subtractive. This Magswitch model, the Magjig 60, works by aligning and counter-aligning two strong neodymium dipole magnets within a field channeling ferromagnetic casing.
Lenz's Law
Get a similar kit here:
From Amazon: BUY NOW Eddy Current tubes
Get some magnetic viewing film here:
From Educational Innovations: BUY NOW Magnetic Viewing Film
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Lenz's Law: a strong neodymium magnet falls slowly down a copper bus bar as though passing through a viscous liquid. Since magnetic fields pass through copper, magneview film reveals the location of the falling dipole magnet. Moving magnetic fields from the falling magnet produce electric currents in the copper. These currents then produce magnetic fields that have the opposite polarity to the initial field. So a falling magnet makes the copper pipe briefly into an electromagnet that repels the magnet. The rectangular copper “pipe” is from a water-cooled electromagnet power supply line, 1.5 x 2 in (4 x 5 cm) in cross-section, designed to supply a steady DC current of 5000 amps. This 40cm long piece weighs in at 6kg and has a 1.5cm diameter hole for cooling water to flow down its center. From a decommissioned particle accelerator magnet.
Viewing the Feel Flux Magnetic Field
Get this device here:
From feelflux.com: BUY NOW Feel Flux
Get some magnetic viewing film here:
From Educational Innovations: BUY NOW Magnetic Viewing Film
From Amazon: BUY NOW Magnetic Viewing Film
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Viewing the Feel Flux Magnetic Field: Magneview film reveals the powerful field of the neodymium magnet as it falls with terminal velocity through the copper tube of the Feel Flux toy.
Ambiguous Object
These type of objects were invented by mathematician Kokichi Sugihara, and you can buy his other books here:
From Amazon: BUY NOW Ambiguous Objects by Kokichi Sugihara
Also available from Amazon (Japan): BUY NOW set of four ambiguous objects with booklet
Similar objects available here- from Etsy: BUY NOW: Ambiguous Objects
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Another illusion design by Kokichi Sugihara of Meiji University in Japan, the inventor of this illusion and art form. A mathematically calculated combination of perspective and the physics of reflection produce this striking illusion that works in many configurations.