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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

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.

UFO Mirascope

Similar devices available here:

From Curiosity Box: BUY NOW: Mirascope with tiny Orange Octopus
From Educational Innovations: BUY NOW Mirascope 
From Amazon: BUY NOW Mirascope 

UFO Mirascope: two parabolic mirrors create a 3D image above the actual object. The image of the tiny alien made here is not a hologram and is produced solely by reflection of light rays between special concave mirrors. Love the space saucer theme on this version. The mirascope design principle was discovered circa 1969 by Landry and Elings at UC Santa Barbara.

Dual Phosphorescence

The UVA and UVC lamps used in this video are available here (well made and reasonably priced professional tools):
From WayTooCool LLC: BUY NOW: UV Lamps

Similar bowls of Mexican onyx can be found here:
From Etsy: BUY NOW: Stone Onyx Bowls

Get amazing phosphorescent calcite crystal samples here (those with a slight pink color will exhibit the glow): 
From Etsy: BUY NOW Optical Calcite Crystal
From Amazon: BUY NOW Optical Calcite Crystal 

Dual Phosphorescence: this stunning “Mexican onyx” bowl is carved out of natural rock that contains phosphorescent calcite that glows in the dark after exposure to ultraviolet light. If exposed to longwave (lower energy) UV-A it glows green, but if exposed to shortwave (higher energy) UV-C it glows a ghostly blue. Phosphorescence is a quantum mechanical phenomenon where high energy UV photons are absorbed by electrons which are then boosted to higher energy levels. The glow comes from these electrons emitting lower energy photons (green or blue in this case) as they jump down through a series of energy levels back towards their ground state. These minerals also fluoresce and look strikingly different under UV illumination. 



Deja Vu II: KInetic Art

Get this amazing work of art and craftsmenship from this source:

From Etsy: BUY NOW: Deja Vu II Kinetic Art

See this other amazing device from this creator: Impossible Marble Machine 

Deja Vu II: astonishing spring powered kinetic art. Crafted from wood this device has two disks (swipe to see partly disassembled) and each has a pattern of curved spokes that can rotate at different rates and direction to produce interesting illusions of motion via moiré interference effects. A ribbon spring drives an ingenious mechanism that uses ratchets (and the rotational momentum of the disks) to create the various visual modes- a half rotation of the disks will result in 20+ minutes of motion. With a full loading of the spring hours of motion will ensue. Another amazing creation by artist and designer William Le. 

Hoptimist Desk Toy

Available in many designs here:

From Amazon: BUY NOW: Hoptimist Sping Toys

Hoptimist Desk Toy: this jovial little guy displays damped harmonic motion- mostly up and down with a slight coupling to horizontal motion- such that his eyes and nose trace out ellipses. A very silly application of Hooke’s law of springs brings this famous Danish design to life. The toy featured is a Bumble Hoptimist created by Hans Gustav Ehrenreich and sold and manufactured since 1968.

3D Phonotrope Spinner

Get this and other amazing phonotrope spinners here:

From Etsy: BUY NOW: Phototrope Animation Spinners 

3D Phonotrope Spinner: spiders on a treadmill! When the rate of rotation matches the rate of the smartphone video process (wait for it) six animated 3D-printed spiders spring into motion. The laser cut acrylic, with precisely placed spiders, is specifically 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. Another fantastic design by Travis at aPyroDesign. 


Ooze Tube Viscosity Contrast

Many colors (and two sizes) to choose from: 

From Amazon: BUY NOW  Ooze Tube 3 Colors 
From Educational Innovations: BUY NOW Ooze Tubes 

Ooze Tube Viscosity Contrast: this set of ooze tube timers comes with 3 mixtures of polyisobutene fluid, each with a different viscosity where green always wins the race: green (thin), yellow (medium), and red (thickest). A curious periodicity in the rate of flow is related to the formation of non-spherical bubbles as the air and fluid trade places (an hour shown in time-lapse). The fluid also displays the “liquid rope-coil effect” where the fluid thread coils and stacks as it lands on the pooling surface.The physics of the liquid rope-coil effect is pretty complex. Here is a recent scientific paper on the topic with nice illustrations. 
Journal of Fluid Mechanics: Multiple coexisting states of liquid rope coiling 


Coupled Oscillator Giraffes

These are mostly available in the Demark Hoptimist shop, but can be ordered internationally here:

From eBay: BUY NOW: Hoptimist Giraffes Art Toy

Coupled Oscillator Giraffes: set one giraffe into motion and the others will join, trading the kinetic energy between each other in an intricate dance. Three identical leaf springs comprise the necks, and the eyes of each giraffe are neodymium magnets. The magnetic repulsion between the heads allows each giraffe to slightly influence its neighbors, hence these oscillating springs are coupled via this magnetic influence which leads to complex patterns of energy transfer with each taking a turn to stand still while the others move dramatically. From the Danish toy maker Ehrenreich (Hoptimist) originally produced in 1972 and recently reissued in the form seen here.


The Planets of Our Solar System to Scale

Made by Jay Fisher- Buy the Solar System! 
From Shapeways: BUY NOW Scale Model Solar System 

See also: this 2D scale model of our Solar System

The Planets of Our Solar System to Scale: 3D printed accurate scale model of 8 planets and Earth’s moon. Wonderful detail allowed by the 3D printing process reproduces the belting on the gas giants. In this model: Earth (diameter = 0.80 cm) and Jupiter (diameter = 9.0 cm)- swipe to see a comparison of the Earth to the Great Red Spot on Jupiter (a hurricane type storm in the Jovian clouds that is more than 500 years old). The ring system of Saturn is color printed on transparency film- swipe twice and note that the inner ring edge to the outermost ring measures 73000 kilometers and could fit almost 7 Earths side by side. The rings around the actual planet are very thin, about 1 kilometer thick, so the transparency film is 250 times too thick to be to scale, and even just the thin 0.010 mm ink layer on the film is 20 times thicker that the actual rings would be at this scale! Made by artist/maker Jay Fisher using images from NASA. 

Glass Hydro-Top

Available in four colors and designs: 
BUY NOW: Glass Water Tops

Glass Hydro-Top: under centripetal acceleration a liquid will flow to create a cylindrical surface parallel to the axis of rotation. This blown glass dreidel contains a small amount of colored water that when spun resembles a blue gemstone banded around the rim. A unique design with fun physics!

Matsuyama's Paradox

Get this and other amazing math puzzles here:

From Etsy: BUY NOW: Missing Square Puzzle

Matsuyama’s Paradox: dissect a large square in to four equal quadrilaterals, rotate and reassemble- to find a small square is missing! Where did the additional area come from? Fun math involved in the design of this puzzle, which illustrates how the concept of area can often challenge our intuitions. Swipe to compare the two assemblies. A precision crafted puzzle by Jeux Efcé game shop. Wikipedia has good details: Missing square puzzle

Rainbow Obsidian

Available here:

From Etsy: BUY NOW: Rainbow Obsidian Carvings 

Rainbow Obsidian: natural volcanic glass with multicolored iridescent layers. When cut and polished at just the right angle with respect to the layers, a pattern of concentric hearts is revealed! The color and iridescent sparkle is due to light interacting with different concentrations of nanoparticle crystals of the mineral hedenbergite in the glass. This carved piece is from a famous quarry near Jalisco Mexico. 

Libyan Desert Glass

Get a sample of desert glass here: 
From Etsy: BUY NOW Desert Glass Specimen 

Get the nice display stand here: 
From Etsy: BUY NOW Caliper Display Stand 

Libyan Desert Glass: mysterious ancient natural glass found throughout the Sahara desert of Egypt and Libya. Current best hypothesis is that the glass was created by a very large meteor that exploded in the atmosphere with so much energy that the earth underneath the blast melted into glass. The glass formation happened about 26 million years ago, but a scientific consensus on how exactly this happened has not been achieved. 

Floating on Mercury

See my other posts: cautious fun with mercury

Here is a discription of the artwork by the artist Calder himself.

Floating on Mercury: metal mercury (Hg) is liquid at room temperature, and it is 13.5 times more dense than water- more dense than many other metals. US coins float on its surface! This demonstration was inspired by the Mercury Fountain of Calder (swipe to see in action) that I posted about a few days ago. In one historical account it was mentioned that visitors at the 1937 World’s Fair would toss coins into the fountain (as folks like to do) and were then astonished that the coins did not sink into the liquid- and hundreds of French francs were skimmed off the surface each day. Caution: contact with the skin and breathing vapors are to be avoided with mercury- make sure to have proper training when investigating this hazardous material. 

Mercury Maze

These vintage items from the 1980s can be found on eBay and Etsy quite often (two available as of this posting): 
From eBay: BUY NOW: Mercury Maze 

Mercury Maze: metal mercury (Hg) is liquid at room temperature, and small blobs of it roll in a peculiar way. The curious properties of elemental mercury are showcased in this vintage toy from the 1970s. Mercury is very toxic and toys like this are now banned in most countries. Mostly dangerous if the toy were to break open- contact with the skin and breathing vapors are to be avoided with mercury. 

Fluorescence of Lapis Lazuli 

Get a sphere and other polished samples of Lapis Lazili here:
From Etsy: BUY NOW: Lapis Lazuli

You will also want an awesome UV flashlight like this one:
From WayTooCool: BUY NOW: High Power UV Light (best UV products and service available)

Fluorescence of Lapis Lazuli: A polished sphere of lapis lazuli, blue with the mineral lazurite, evokes the form of a banded planet with swaths and speckles of other minerals such as calcite, pyrite, sodalite, and hauynite. The beam of a long wave UV flashlight reveals an astonishing transformation of appearance where the banding on the sphere glows bright yellow via fluorescence of the hauynite inclusions. The colorful glow comes from complex quantum mechanical behavior where molecules of some of the minerals absorb high energy UV photons and then emit this energy out in the form of lower energy photons- the physics of fluorescence. 

Mercury Fountain of Calder

This fountain is on display here:

Visit: Fundació Joan Miró

Here is a discription of the artwork by the artist Calder himself.

See my other posts: cautious fun with mercury

Mercury Fountain: Some amazing physics fun from my January holiday in Barcelona- a fountain of flowing metal with 150 liters of mercury filling a two meter in diameter reflecting pool. This fountain is kinetic art created for the 1937 World’s Fair in Paris by the famous artist of mobiles, Alexander Calder, and features aspects of his trademark design. Given the density of mercury at 13.5 g/ml, the liquid in the fountain weighs in at roughly 2000 kg (4500 lbs), and at the bottom of the fountain Calder utilizes the small but massive droplets to impact a paddle which keeps the mobile components in motion. This work also has important historical significance as a political statement against injustice. Note that the top of the mobile includes, in cursive, Almaden, in remembrance of the mercury mining town that suffered under Franko’s siege during the Spanish Civil War in 1936. The fountain now sits behind thick sealed glass on display in the Joan Miró Foundation museum atop Montjuïc in Barcelona.

Heart Gears

Get a nice 3D print made here:
From Etsy: BUY NOW: Heart Gears

Or print it yourself:
From Thingverse: Download Free: Heart Gears Print Files

Heart Gears: This 3D print is guaranteed to put your heart in a twist- comprised of eight bevel gears attached to an octahedron center block, with the axis of each gear oriented to the center of each face of the octahedron. Rotate any one gear 360 degrees and the heart shape will reform. Another amazing design by Emmett Lalish, first printed in 2014.