Recent Posts

Fiber Optic Spray Lamp

A wide variety of similar lamps can be found on Etsy: 
From Etsy: BUY NOW Fiber Optic Lamps

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Fiber Optic Spray Lamp: a vintage fiber optic lamp sold by RadioShack back in the 1980s. The fiber bundle is illuminated by a lamp in the base and the color shifting patterns are generated by a rotating color wheel placed between the light source and the fiber optic bundle. Physics of internal reflection and refractive index to channel light through a fiber.

Electric Motor/Generator Demo

Kits with these motors and other accesories available here:

From Amazon: BUY NOW: DIY Motor kits 

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Electric Motor/Generator Demo: fun physics fact- motors can be used as generators (and vice versa) as shown here with two identical inexpensive 3V motors each with a mounted pulley and connected by a belt. One motor converts the electricity of the batteries to rotational motion, the other converts rotation back to electricity to light the bulb. Note the speed of rotation slows when the load of the lightbulb is connected (change in pitch can be heard).

Tumble Rings

I made this set of tumble rings from reading Martin Gardner's description in his famous mathematical recreations books- highly recommended: 
From Amazon: BUY NOW Knots and Borromean Rings by Martin GardnerDescribes the Tumble Rings 
and Donald Simanek has a great and short tutorial here: on his Toys and Tricks page
or get one preassembled here: From eBay: Tumble Rings

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Tumble Rings: the links in this chain are connected in a special way such that the top ring appears to tumble to the bottom- a topological curiosity, and compelling illusion! The math and details of construction are thoughtfully presented by Martin Gardner in his Scientific American column from 1988. 


Holographic Apple Pendant

This new hologram often available here:

From Etsy: BUY NOW: Apple Pendant Hologram

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

Hologram Apple Pendant: another new holographic image on the market. When lighted from a specific angle an apple appears- in 3D and looking real enough to eat. Astonishing physics of constructive and deconstructive interference of light from a film thinner than a sheet of paper. 

Rheoscopic Fluid Lamp

Get this affordable lamp here:

From Amazon: BUY NOW: Crystal Fluid Lamp

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Rheoscopic Fluid Lamp: a fun novelty lamp in the shape of a crystal featuring illuminated rheoscopic fluid in turbulent flow. The mesmerizing swirls and flow are made visible with tiny flake crystals of mica catching the colorful LED light in the special fluid. Rheoscopic fluids were developed by Paul Matisse in the 1970s to allow visualization of fluid motion. This affordable lamp is produced by EnhanceGaming 

 

Color Flame Candle Spectrum

Color Flame candles available here:
From Amazon: BUY NOW: Color Flame Birthday Candles

Get the diffraction grating used in the video here:
From Amazon: BUY NOW: Diffraction Grating

or paper glasses version as party favors!
From Amazon: BUY NOW: Diffraction Glasses

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Color Flame Birthday Candle Physics: the colored parts of these candle flames are due to excitation of specific chemical elements mixed into the wax. When viewed through a diffraction grating some of the prominent emission frequencies (electrons jumping between quantum energy levels) can be seen as “ghost” images to the side as the grating separates the light into the spectrum emitted by each flame. Most notably the yellow candle has a strong yellow/orange emission line from sodium, the red candle has similarly strong red and orange lines from strontium, and the blue and green candles have a bunch of overlapping violet/blue/green lines from copper and probably potassium. Note that glowing tip of the wick creates a thin line of the full continuous spectrum. 


Caustic Projection Optical Element

This optical element is a component of this affordable Laser show device:
From Amazon: BUY NOW: Aurora Laser Show Projector

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Caustic Projection Optical Element: the intricate geometries of light due to refraction through various curved surfaces of transparent plastic. A 488 nm cyan laser pointer is refracted through an optical element with lumpy surface features which create this aurora/nebula effect. When light rays refract through a curved surface they concentrate into bright patches called caustics, often with cusp singularities (sharp points) and intricate threads of shadow. 

Pixeluxe Pixel Crystal

Get this exact device here:
From Amazon: BUY NOW: Pixel Crystal

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Pixeluxe Pixel Crystal: pixelate anything as you view the world through this hand held optical device. Made of optical quality glass, the geometry is that of two concave cylindrical lenses, one on each side, and set at 90 degrees to each other- this shrinks the image as any concave lens would do. Pixelation is achieved by constructing the curves out of 16 long skinny facets across the 36 mm width, producing the 16-bit resolution effect. My color lithophane of a famous physicist serves as my first object to pixelate. 

Holographic Optical Top

Vintage versions available on Etsy: 
From Etsy: BUY NOW Laser Disk Top 

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Holographic Optical Top: a vintage sheet metal disk top spins with patterns created from reflective diffraction gratings- seen here illuminated by a light panel and flashlight- each producing illusions of depth and curious motions. Produced in the 1990s as “Laser Dazer” spinning disks. 


Paradox Inverse Flow Timer

Available here:
From MoMA: BUY NOW: Paradox Inverse Timer

Get similar inverse timers here:
From Amazon: BUY NOW: Inverse Sand Timer

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Paradox Inverse Flow Timer: inverse of the sandglass- tiny plastic beads are less dense than the water and thus ascend to the top of the container under the influence of a buoyant force in accordance with Archimedes' principle. This timer takes about 5 minutes to complete shown here at normal speed for the first part of this video, and the second half is condensed in time-lapse.

Magnetic Chaotic UFO Pendulum

These chaotic UFO pendula are still available on eBay: The Visitor UFO 

Click here for similar chaotic systems

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Magnetic Chaotic UFO Pendulum: The ufo in this vintage 1997 toy is a pendulum bob with an attached magnet and the base has a battery and simple coil circuit that gives the bob a tiny push each time it swings through the center. An array of 5 permanent magnets are also hidden in the wood base and these magnets produce the chaotic motion- not random, but very sensitive to slight differences in initial launch conditions. A clever design feature connects the pendulum to the top mount with yet another magnet, and this sharp contact point greatly reduces friction such that a fresh 9V battery in the base will keep the pendulum in motion for many days. Sold as “The Visitor” by DaMert Company out of Berkeley CA 1997. 

Tesla's Egg of Columbus

Get this amazing (and affordable) reproduction here:
From engineDIY: BUY NOW: Tesla's Egg of Columbus
This version comes with a 35mm solid aluminum sphere. 

Get the aluminum phiTOP "egg"  here: BUY NOW phiTOP 

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Tesla’s Egg of Columbus: an aluminum ellipsoid egg (PhiTOP) mysteriously spins and stands upright in this modern version of Tesla’s famous demonstration from the 1893 World’s Fair in Chicago that first showcased the principles behind wireless power transfer and his AC induction motor. The base has no moving parts- instead special copper windings (very similar to Tesla’s original design) form four electromagnet coils on a circular steel core, and a special circuit supplies each with AC currents in such a way that a rotating magnetic field is created. This rotating magnetic field from the coils under the concave glass induces electric eddy currents to flow in the aluminum ellipsoid- these currents then create their own magnetic field which oppose the initial fields underneath and pushes the ellipsoid to spin. Finally, the ellipsoid top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top. 

 

 


Simple Stirling Engine

Get a simple yet amazing model engine here:

From EngineDIY: BUY NOW: Simple Stilring Engine

See other featured DYI devices here: EngineDIY Models

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Simple Stirling Engine: Perhaps the simplest piston engine ever devised- a single piston powered by a tiny alcohol lamp. Glass components allow a view of the internal workings of this design, and the interesting startup behavior from oscillation to full rotation. Heat engines produce mechanical motion from a difference in temperature- here the piston side is near room temperature (the central aluminum post is an excellent conductor and acts as a heat sink as the gas flows through), and the test tube is kept at high temperature via the flame, with metal fibers to help conduct the heat into the air (this component is called the regenerator). Swipe to see the elegant assembly of this model, and swipe again to see the engine power down. This external combustion design is attributed to Scottish engineer Robert Stirling back in 1816.

Thermochromic Tea Set

Get this affordable set here:
From Amazon: BUY NOW: Color Chaging Dragon/Pheonix Tea Set

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Thermochromic Tea Service: pour in hot water and watch a dragon and a phoenix materialize in vivid color. This set is the most colorful I’ve seen and is a new addition to my collection of thermochromic ceramics. The color change employs leuco dyes, thermochromic chemicals that have two reversible forms, one colorless when warmed above a threshold temperature. 


Rainbow Twirler

Get one here: 

From Amazon: BUY NOW: Rainbow Twirler

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Rainbow Twirler: shaped by angular momentum and centripetal acceleration- when the speed of the ribbon is faster than the flicker fusion frequency of human vision it looks like a bubble. As the rotation speed increases the shape flattens- similar to the way the Earth bulges due to its rotation. Found this fun motorized base for this item in a toy store last week.

Precession of a Gyroscope 

Inexpensive ones work fine- get one here: 
From Amazon: BUY NOW Gyroscopes 

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Precession of a Gyroscope: in defiance of gravity this gyroscope hangs attached only at one end. The physics and vector nature of angular momentum! Notice that as the disk of gyroscope slows down, its axis begins to tilt downward, but interestingly its speed of precession around the vertical increases. Timed my catch just before it fell. 

Lenticular Invisibility Sheet

This item came to me in my Curiosity Box subsciption:
Get (or give!) a Curiosity Box subscription here: JOIN NOW: The Curiosity Box

Inexpesive "lenses" showing this effect available here: 
From Amazon: BUY NOW: Lubor's Lens

Giant versions availabe here:
From Etsy: BUY NOW: Invisibility Lens

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Lenticular Invisibility: this thin acrylic sheet is comprised of tiny cylindrical lenses which can allow images to be out of focus along one dimension which blurs thin images and hides them. This 70 lens per inch sheet is part of a lenticular optics kit that came as part of my Curiosity Box subscription- amazing and fun!