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Exothermic Crystallization Heat Pack

Available in many sizes and colors: 
From Educational Innovations: BUY NOW Click Activated Resuable Heat Pack 
From Amazon: BUY NOW Click Activated Reusable Heat Pack 

Exothermic Crystallization Heat Pack: real-time instant crystallization of a supercooled solution. Solid sodium acetate melts at 137F (58C), but it will stay in liquid form as it cools to room temperature creating a supersaturated and supercooled state- the solution stays in the liquid form until a seed crystal, provided by clicking the metal disk, initiates the solidification. The resulting white crystal is actually quite hot; solid states have lower energy than liquid states and thus the difference in energy is given up as heat that raises the temperature back up to the melting temp, and you can see in the few seconds of the video that the temperature rises from 26C to 34C. This pack is reusable many times- just boil the pack until all the crystal is melted to reset. 

Fluorescence and Birefringence in Calcite

Get a sample here: 

From eBay: BUY NOW Optical Calcite Crystal 
From Amazon: BUY NOW Optical Calcite Crystal 

Get inexpensive polarizing filters here: 
From Educational Innovations: BUY NOW Polarizing Filter Sheets

Need a UV laser pointer? Get 3 lasers (one of each color) for under $10 (including S&H): 
From eBay: BUY NOW red+green+blue(UV) laser pointers

Fluorescence and Birefringence in Calcite: two samples of calcite- each with different impurities that produce blue fluorescence for the small crystal and red fluorescence for the larger one under a 405nm violet laser. Also one can clearly see that the single laser beam takes two paths through the crystals- the speed of light in a calcite crystal depends on polarization because the refractive index is different depending on the polarization orientation of the light transmitted through it (swipe for demonstration). As a polarizing filter is rotated 90 degrees, one image appears and the other vanishes, showing that the polarization orientation of the light of the two images is indeed perpendicular. In addition the elegant rhombohedral nature of calcite crystals is obvious in this sample.

Scale Saturn with Ring System and Earth

Made by Jay Fisher and available here! 
From Shapeways: BUY NOW Saturn 
Buy the whole Solar System! 
From Shapeways: BUY NOW Scale Model Solar System 

Saturn with Ring System and Earth: 3D printed accurate scale model of the Earth (diameter = 0.80 cm) and Saturn (diameter = 7.6 cm). The ring system is color printed on transparency film- 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.


Satisfying Hexagons

Get this 3D print here (your choice of colors):

From Etsy: BUY NOW: Satifying Hexagons

Satisfying Hexagons: this delightful kinetic art manipulation toy features 19 nested hexagons within a hexagonal frame. Embedded magnets allows one to move the central hexagon from behind creating interesting visual effects. A 3D print created by @i.am.the.lazy.engineer- indeed oddly satisfying!

Element 10: Neon 

Luciteria (highly recommended) sells this cube and 80 other elements in many formats- start your collection today! 

From Luciteria: BUY NOW: Lucite Cube Element 10 Neon

Need a mini Tesla Coil? Click here for details: Mini Tesla Coil 

Element 10, Neon: a pure sample of the famous noble gas in a glass ampule encased within a lucite cube. But how can we know that the glass tube is actually filled with neon gas? If the sample is brought near the 50,000 Volt high frequency electric field of a miniature Tesla coil, the gas will glow with the characteristic orange light from the electron energy transitions specific only to neon. Note that the glow deceases as the sample is moved away from the coil in proportion to the electric field intensity- and that there is an excitation threshold, the gas needs a higher intensity (closer to coil) to initiate the glow discharge but will still glow when moved further away. 

Popsicle Stick Bomb

Craft sticke work great:

From Amazon: BUY NOW: Stick Bomb Supplies

Amazingly: There is a Wikipedia entry on Stick Bombs and their physics

Popsicle Stick Bomb: a form of simple tensegrity, the elastic potential energy of the bent sticks is dramatically released under application of a slight concussive force such as an impact with a table top- shown here in forward and backward slow motion (swipe to see three more explosions). Shown here is one of the simplest constructions with 5 flat sticks woven into a spring-loaded configuration held in place by friction and tension induced by the bending of the wood. A nice demonstration of energy conversion- potential to kinetic.


Micro Racer in a Glass

These micro racer cars are sold under many brand names, and most come with a clear sphere to demonstrate this centripetal acceleration phenomenon. 

From Amazon: BUY NOW: Micro Racer + Sphere

Micro Racer in a Glass: This tiny battery powered car overcomes gravity through centripetal acceleration and slight friction with the glass surface. With sufficient velocity the surface normal force supplies the centripetal acceleration. The car’s battery last for many minutes and is USB rechargeable.

Coins and Eddy Currents

I found this apparatus at American Science and Surplus many years ago. Follow the link below to find similar demonstrations of eddy currents and other electromagnetic toys and demos: 
 
physicsfun shop: 
Magnetic Toys and Demos 
Coins and Eddy Currents: coins interacting with powerful neodymium magnets. Eddy currents are generated when conductors move near magneticfields- these currents then produce opposing magnetic fields. Coins that are made of good conductors fall slowly through the magnets (quarters, dimes, and pennies) and those made from poor conductors fall faster (nickels).

Tesla’s Egg of Columbus

PhiTOPs are available in Aluminum, Brass, and Copper (most conductive!): 
From Etsy: BUY NOW PhiTOP in Copper 
From Etsy: BUY NOW PhiTOP in Brass 
From EI: BUY NOW PhiTOP in Aluminum 

Click here for more on the PhiTOP and using magnetic induction to spin it up. 

Tesla’s Egg of Columbus: a copper 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. Rotating magnetic fields from under the wooden platform induce electric eddy currents to flow in the copper PhiTOP- these currents then create their own magnetic field which oppose the initial fields underneath and pushes the PhiTOP to spin. This version differs from Tesla’s in that the rotating magnetic fields are created by, well, a pair of rotating neodymium magnets (revealed by lifting the top platform in this model). Credit to astrophysicist Kenneth Brecher, the creator of the PhiTOP, and this unique means of using a common lab magnetic stirrer to create the induced currents. Finally, the ellipsoid top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top. 


Impossible Bolt

Only available from these aritist/craftsmen: 

From Etsy: BUY NOW: Impossible Bolt & Nuts

Impossible Bolt: one nut threads on clockwise as normal- the other threads on counterclockwise on the same bolt! Not impossible- but carefully engineered and machined. Swipe for partial hint on mechanism. This puzzling curiosity was inverted by Scott Eliott and machined in solid brass by puzzle crafters Steve Nicholls and Ali Morris of TwoBrassMonkeys.

Faraday Train

Here's the parts to make your own: 
From eBay: BUY NOW Neodymium Spheres 15mm 
From Amazon: BUY NOW Bare Copper Wire 10 gauge 

The wire used for the Faraday Train has to be bare- so make sure it does not have any kind of clear coating on it. The solid grounding wire sold at hardware stores works great. 

Here is a nice description of the Faraday Train and the physics of its propulsion

Faraday Train: two magnets, one battery, and a coil of bare copper wire are the simple essence of this self propelled craft. The magnets conduct electricity, thus when put in contact with the coil current will flow creating a solenoidal magnetic field in the vicinity of the battery, which in turn pushes on the magnets at each end of the battery moving the craft along. The spherical neodymium magnets used allows the craft to slide along the coil with minimal friction. 

How a Slinky Falls

Get the classic here: 
From Amazon: BUY NOW Mini Slinky 

Get a giant version of the slinky here! 
From Educational Innovations: BUY NOW Giant Slinky: Super Wave Spring 

How a Slinky Falls: amazing physics demonstration with this classic toy. The center of mass of the slinky spring falls with an acceleration of g- note in this slow motion video that the bottom of the slinky does not move until the spring is fully collapsed. Hooke's law plus gravity! 


Universe Sphere

Created by Clemens & Christoph of CinkS labs: Available in a cube too! 
From CinkS Labs: BUY NOW Universe Sphere

Special offer for physicsfun folowers: Use code POCKETUS and get a free Pocket Universe with your order of a sphere. Just add the Pocket Universe to your cart and apply the code. 

Wikipedia has a good description of the distribution of galaxies on this scale 

Click here for Milky Way in a Sphere

Universe Sphere: 380000 laser etched dots, each dot representing a galaxy of stars, reveals the largest scale structure of our universe. This glass sphere contains a 3D mapping of galaxies in a volume of our universe spanning 800 million lightyears in diameter, and shows the clumping and distribution as seen by automated telescopic surveys such as that found in the Sloan Digital Sky Survey data. Hold a chunk of the universe in your hand!

Tesla's Plasma Mug

This plasma mug was sold in the 1990s but can be found on eBay often:
From eBay: BUY NOW: Plasma Mug

An improved and beautiful version sold here:
From Etsy: BUY NOW: Plasma Mug

Tesla’s Plasma Mug: this double walled glass mug glows orange from the excitation spectrum of neon gas at low pressure. The base contains a high frequency transformer that generates high voltage electric fields (but at very low current) from 8 AA batteries- which excites the neon to glow, and also serves as a coaster. This crazy item was produced by Can You Imagine Toys in the 1990s- perhaps Tesla himself would have served a good beer in this mug! 

Vibration Unthreading

Get inexpensive small motors and accesories for DIY projects here:
From Amazon: BUY NOW DC Motors Kit

A DIY project to see if just shaking a bolt at the right frequency could make a standard nut rotate and fall off. Similar physics to the phase locking propeller toy featured in my last post. Motivated by videos seen on Instagram where a brass bolt is placed in magnetic putty and the nut mysteriously rotates up and off- now convinced that vibration is how that effect is produced. Here a small DC motor spins an offset mass to produce the vibrations.


Time's Up

Similar timers available from these sources: 
From eBay: BUY NOW 
Inverted Timer 


From Amazon: BUY NOW 
Inverted Timer 


Time's Up: 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 almost exactly 6 minutes to complete shown here at normal speed for the first half of this video, and the second half is condensed to 24 seconds in time-lapse. 

Tension Suspension: Tensegrity Scuplture

I made this device from these components:

From Amazon: BUY NOW:  heavy guage copper wire (for frame), inexpensive necklace chain (for connections), and hobby wire (to fasten chain to copper frames).

Check out these other Tensegity toys I've posted. 

Tension Suspension: an interesting take on tensegrity where one heavy wire frame seems mysteriously suspended above another. This sculpture features strings (chains used here to make it look more dramatic) in tension equilibrium, with the top wire frame hanging from the bottom frame by the strand in the center, and the other three strands in tension to keep it from tipping over. This configuration is related to the concept of tensegrity invented by Kenneth Snelson and made famous by the architect Buckminster Fuller in 1949.

Aquarius Fountain Lamp

These fountains are individually made by the artist hence they are priced as art reflecting the labor involved: 
From Etsy store of Stephen Co : BUY NOW 
Aquarius Fountain Lamp

Aquarius Fountain Lamp: an oscillating stream of water is illuminated by strobe lights to reveal underlying structures and forms typically hidden from our vision. With the help of programmable micro-controllers, strips of addressable RBG LEDs are made to flash in sequences that make the water stream appear to move upwards, change colors, and split into multiple braided streams. Art meets physics and clever technology in this wonderful creation by computer engineer Stephen Co. With sincere appreciation to Stephen @northerncircuits for sending me one of his hand crafted high tech fountains.