Get the print files here:
From Thangs: Download Now: Gear Ball
Or get one printed in the color(s) of your choice:
From Etsy: BUY NOW: Gear Ball
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Gear Ball: another amazing gear assembly with an abstract geometry that would be very hard to make without 3D printing with four large and four small conical cogs. A super fun creation by maker/designer Ruven Bals.
Get this nice spritl level here:
From Amazon: BUY NOW: Bubble Spirit Level
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Spirit Level in Accelerated Frame: rotation always involves acceleration as demonstrated by this beautiful sprit level. The level can correctly determine the direction of gravitational pull only when it is not undergoing acceleration.
Amazingly this motor is available for less than $10 US.
From Amazon: BUY NOW: Brushless Motor/Generator with LED
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Electric Motor/Generator: this inexpensive and common motor can also serve as a generator of AC electricity- here lightning an LED when the shaft of the rotor is spun by hand. Most electrical energy we use today is produced by moving a magnet near a coil of wire (known as Faraday’s law of induction) to produce an electric current. Removing the permanent magnet casing reveals this design to use 9 separate copper windings. I made a transparent second rotor with six neodymium magnets- and when these magnets are made to move near the windings the LED again lights with the flow of current.
Availabel here:
From Etsy: BUY NOW: Uphill Ramp Illusion
or get the 3D print file here:
From Thingverse: Download Now: Uphill Illusion
Learn more: The amazing illusions of Kokichi Sugihara
See the many other Sugihara Illusions: in my collection
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Rolling Uphill Illusion: the ball bearings seemingly roll uphill as if attracted by magnets of some kind. What’s going on? Swipe for reveal as it is truly a matter of perspective. A wonderful take on an illusion invented by Kokichi Sugihara of Meiji University. 3D printed by my good friend @zathras5 (Roger Key) from a file designed by Julian Hardy.
The illusion pen is available here:
From Amazon: BUY NOW: Spiral Illusion Pen
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The pen holder came to me from my friend Tim Rowett a few years back- I will post again if I can find some for sale.
Unstable Equilibrium Pen Holder: the “pen plank” stand is of simple construction, sliced and drilled at an angle. When combined with a pen the center of mass of pen + stand is directly above base of stand- allowing the assembly to defy gravity. A perfect stand to display my spiral barber pole illusion pen!
Get this well designed kit here:
From Kontax: BUY NOW: Tensegrity Stand
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Tensegrity Mobile Stand: thin cables levitate and support a smartphone at an angle in this high tech precision machined version of the tensegrity concept, invented by Kenneth Snelson and made famous by the architect Buckminster Fuller in 1949. This stand by Kontax Engineering Ltd came as a kit and was a lot of fun to assemble.
Get magical table centerpiece kits here- many themes for the floating items available:
From Amazon: BUY NOW: invisible polymer centerpiece kits
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Holiday Decor Physics Magic: sparkling ornaments seem to defy gravity within this glass vase table centerpiece. The snowflakes and shiny baubles are immersed in spheres of hydrophilic poly-acrylamide polymer which have an almost identical index of refraction as that of water- thus when submersed they become practically invisible. Note the elasticity of these spheres from the way they bounce, while at the same time they refract their surroundings as a spherical lens. These super absorbent spheres start as hard crystals with a radius of about 1mm and grow to 7mm when immersed in water for an hour or so.
Get this well designed kit here:
From Amazon: BUY NOW: Tensegrity Stand
Note: this site contains affiliate links for which I may be compensated
Mini Tensegrity Table: thin but strong cables provide the support in this precision machined version of the tensegrity concept, where flexible tethers under tension are placed in balance and create an illusion of levitation. The first tensegrity structure was invented by Kenneth Snelson in 1949 and the concept was later made famous by the architect Buckminster Fuller. This stand by Kontax Engineering Ltd came as a kit and was a lot of fun to assemble.
Similar spinning scupture available here:
From Art of Play: BUY NOW: Mezmoglobe Kinetic Object
Get this easy to assemble kit here:
From Amazon: BUY NOW Simplest Motor Kit
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Electric Motor: in its simplest form!- coil, magnet, and battery. The wire of the coil has an insulating coating- and this coating is carefully scrapped off one side on each end. When current passes through the coil it becomes an electromagnet and the permanent magnet repels it making it spin- as it turns the currents goes on and off depending if the copper posts are in contact with the bare wire (current on) or the still insulated wire (current off). I have motors with fewer parts- but they operate on more complex principles.
The 3D Print files are available here:
From Printables: Download Now: Snowflake Inversion Fidget
Snowflake Inversion Fidget: For a given shape of elastic ribbon, what would it look like if flipped inside-out? Surprising results often follow- in this case a much differently shaped snowflake appears. This 3D print can switch back and forth but the six fold symmetry remains. Designed by Thomas Draper and expertly printed by Jason Veatch.
The needed snowflake decoratons and polarizing film are affordably priced here:
From Amazon: BUY NOW: acrylic snowflake decorations
From Amazon: BUY NOW: Polarizing film
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Polariscope Holiday Decor: while wearing my polarizing sunglasses I happened to notice psychedelic and fractal like colors appearing within these snowflake decorations, inspiring further exploration and production of this display. What’s going on? Polarized light revealing the hidden rainbows due to internal stresses imposed on polymer materials such as these snowflake ornaments of polystyrene, a technique used to model stress distribution patterns in engineering. Place the polymer samples between two linear polarizer filters and the internal stresses created by the molding process during manufacturing produce colors through birefringence due to photoelasticity.
Fairly simple to make- here are the inexpensive supplies needed to make a few of these motors.
AA batteries have a diameter of 14.5 mm, so a bottom magnet with a diameter of 15 mm is just right:
From Amazon: BUY NOW Neodymium Disk Magnet
Wire that looks and works well is just 10 gauge ground wire. Inexpensive and available at any local hardware store-- or order a small quantity here:
From Amazon: BUY NOW 10 gauge Copper Wire
Note: this site contains affiliate links for which I may be compensated
Wikipedia has some good details on the physics of homopolar motors
Homopolar Motor: a minimalist electric motor- battery, wire, and magnet. This type of motor does not need a commutator- the polarity of the electromagnetic coil does not need to reverse. The challenge with this design is balancing the coil to center on the battery as it rotates. A favorite DIY physics toy!
Get a sample to make your own display here:
From Amazon: BUY NOW: Heavy Water
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Heavy Water: D2O is H2O with every H (regular hydrogen, main isotope nucleus=proton) with a D (rare isotope hydrogen nucleus=proton+neutron). So D, deuterium, has close to twice the mass of hydrogen. Each vial has exactly 10 grams of each liquid- note there is less D2O because it has more neutrons which makes it 11% more dense than regular water.
Get a similar device here:
From Educational Innovations: BUY NOW Fire Piston Demonstration
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Antique Fire Syringe Demo: rapid adiabatic compression creates enough heat to ignite and incinerate a small ball of cotton. This antique device has a cylinder of thick glass and a piston made of hard wood. The seal is accomplished with a thin gasket of oiled leather. The cotton ignition source is attached to the end of the piston with a loop of thin wire. Similar to the physics of how Diesel engines ignite fuel without a sparkplug. Adiabatic processes are those in which heat does not flow from the system to the environment, achieved here by the short duration of the compression- to get a flame the compression has to be done quickly with some force.
Many nice specimens can be found here:
From Etsy: BUY NOW: Fluorescent Mineral Specimens
The UV lamp used in this video is available here:
From WayTooCool LLC: BUY NOW: UV Lamps
Super nice 365 nm UV flashlights available here:
From Amazon: BUY NOW: Convoy UB Flashlight
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All-Wave Triple UV LED Torch: a favorite new toy to explore mineral fluorescence and phosphorescence- this hand held device delivers three different frequencies in the ultraviolet spectrum: 255nm from UVC, 310nm from UVB and 365nm from the UVA range. UVC offers the most energetic photons and we get bright orange fluorescence in calcite, bright green from willemite, and phosphorescent after glow, including a ghostly blue in a calcite rhomboid that fades after the lamp is switched off. Under UVB we get a bright red from another form of calcite (with trace percent Manganese activator). And under the long wave UVA scapolite glows bright yellow, fluorite glows purple, and the calcite rhomboid glows pink instead of blue. Such ordinary looking rocks, yet with complex reactions that are revealed depending on the frequency of the illumination. Made by Way Too Cool LLC
Just thread a rubber band through two of these drilled steel balls and you are ready to go!
From Amazon: BUY NOW: Drilled Spheres
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Centripetal Spheres: two ball bearings connected by a rubber band orbit each other as energy oscillates between elastic potential energy and rotation kinetic energy. Just wind up the rubber band and let go. When the rubber band has unwound the rotational inertia of the bearings winds it back up until it changes direction. The process repeats until the initial energy is dissipated through friction.
Get this device here:
From Amazon: BUY NOW: PDLC Smartwindow Sample
Note: this site contains affiliate links for which I may be compensated
and click here for the balancing dragon toy
PDLC Electric Field Induced Transparency: when a voltage is placed across Polymer-Dispersed Liquid-Crystal film, long skinny molecules align with the electric field allowing light to pass through without scattering- with the field off the molecules thermally randomize and then do scatter the light passing through, producing a milky white translucent appearance. This sample of a “smart window” is powered by a 1.5 Volt AA battery and has very thin metallic coating on the front and back. A fun demonstration of electrochromic materials.
Gallimum metal and a silicone mold to produce the spoon- available here:
From Amazon: BUY NOW: Gallium Mold Spoon Kit
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Disappearing Spoon: the metal gallium has a melting point of 30°C (86°F) and will melt quickly when exposed to tea temperature hot water- or melt in one’s hand if handled too long. This spoon was made with a silicone mold (swipe to see process), and feels and sounds just like a regular spoon, except solid gallium is brittle and the spoon can shatter like glass if dropped. An amazing parlor trick as well as a classic and historical class demonstration.
