All physicsfun toys

Fluorescence and Birefringence in Calcite

Get a sample here: 

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

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.

spYke Ferrofluid Display Cell

Check out the Etsy page of CZFerro: imaginative and quality ferrofluid display cells 
On Etsy: BUY NOW Magnetic Fluid Sculptures 

spYke Ferrofluid Display Cell: another spectacular display cell by czferro featuring a colloidal ferromagnetic liquid in a specially prepared water-alcohol suspension. The orange background highlights the curious spiking behavior of the black ferrofluid- a result of the interplay between magnetic force and surface tension between the liquids. 

Kinetic Sandscape

This version is a bit pricy, but very well made and shows the phenomena of spontaneous stratification better than any other versions I've seen: 
From Amazon: BUY NOW 
Kinetic Sandscape 

Kinetic Sandscape: the phenomenon of spontaneous stratification is a striking feature of this sand motion desk toy. Typically pouring stuff together results in further mixing, yet here, when the sand mixture descends through a gap in the air bubbles, the resulting pile is ordered into sorted layers. The larger rounded dark grains separate from the smaller sharp-edged white grains forming the layers you see here. The darker grains alone would stack into a steeper pile (larger angle of repose) than the white which would form a less steep pile. The stratification process is a slow one in this device, here about 30 minutes have been condensed to the 60 second IG format. 

Heat Pipe

The heat pipe kit includes the pipe and a copper rod: 
From Educational Innovations: BUY NOW Heat Pipe Demo Kit 

Here is the liquid crystal sheet used in the video (range 20-25C): 
From Educational Innovations: BUY NOW liquid crystal thermometer sheet 

Heat Pipe: a device that transfers heat with great efficiency- as demonstrated by this fantastic kit from @educational_innovations . Here a liquid crystal goes from green (room temp) to black (near freezing) showing the heat transfer to a piece of ice through a heat pipe (top) and a similar sized piece of solid copper rod (bottom). As you can see the heat pipe cools much faster than the copper rod even though copper is an excellent conductor of heat. The heat pipe is a thin shell of copper that surrounds a tube of sponge like material filled with some water vapor and sealed with a low pressure inside. The heat is transferred from one end to the other by the phase transition of water- at the warm end water in the sponge evaporates into vapor absorbing heat energy, the vapor travels down the hollow core to the cold end where it condenses into liquid releasing heat energy. The water is wicked by the sponge to the warm end and the process repeats. Heat pipes like this one pull heat away from the CPUs in modern computers preventing them from melting. The amazing heat transfer ability is clearly felt in the fingertips if one places the copper rod and heat pipe into a glass of ice water-the heat pipe immediately gets cold! 

Infinity Mirror Lamp

Inexpensive and a few models to choose from: 
From eBay: BUY NOW Infinity Mirror Sphere Lamp 

Also sold as a lightbulb: 
From Amazon: BUY NOW Infinity Mirror Firework Bulb 

Infinity Mirror Lamp: illusion of depth from multiple refections. This glass bulb sphere is partially coated inside and out with a thin metal layer. The metal layer is made thinner in a pattern of small circles to produce iridescent colors through thin-film interference effects. When lit from within by white LEDs, multiple reflections on the curved contour create the firework like spray of light and color. So much physics going on in this inexpensive novelty lamp!

Aqua Drop Puzzle

Three models/colors to choose from: 
From Amazon: BUY NOW Aqua Drop Puzzles 

From eBay: BUY NOW: Aqua Drop Puzzle

Aqua Drop Puzzle: a superhydrophobic coating allows this dexterity puzzle to use a drop of water as the "pinball". The white surface is a silica nano-coating that makes water roll off- a condition sometimes referred to as the Lotus effect because leaves of the Lotus plant have this property. 

Precision Tippe Top

Get a flip over tippe-top here:   

STEMcell Science Shop: BUY NOW Tippe-Tops 

Precision Tippe-Top: spinning things often have surprising physics! This aluminum version of the famous flip-over top works better than any I’ve seen. Friction with the desk surface provides a torque that acts on the existing angular momentum of the top to flip it over. The top will stay flipped until the spin rate slows down enough to where its center of mass pulls it back to the resting position.

Reaction Rocket

The essence of a great physics toy: simple design showing comlex physics 
From Educational Innovations: BUY NOW Reaction Rocket 

Reaction Rocket: projectile launch via momentum transfer in slow motion. The superball/straw base bounces off the table top and then immediately collides with the bottom of the rocket sending it off with a velocity slightly less than 3 times the velocity of the rising ball (true if the ball is more than three times the mass of the rocket). Newton's third law in action! Note that the rocket rises much higher than the drop height (up to 9 times higher).

Pythagorean Puzzle

Available here: 
From Creative Crafthouse: BUY NOW Pythagorean Puzzle

Pythagorean Puzzle: a proof, in physical form, of one of the most famous equations concerning the sides of any right triangle. The area of a square with side c of the hypotenuse is indeed equal to the sum of the areas of the squares of side a and b. This kit also allows at least two other ways to prove this theorem named after the famous Greek mathematician from 500 BC. One of the most used formulas when calculating vectors in physics classes ?

Hydrophobic Water Maze

Wonderfully well crafted and available from this shop :
From Etsy store TheSmallestWorkshop:

BUY NOW Hydrophobic Water Maze

Hydrophobic Water Maze: a superhydrophobic coating allows this dynamic puzzle to use a drop of water as the "pinball", which can split into multiple smaller drops and recombine along the way. The wood surface is treated with silica nano-coating that makes water roll off- a condition sometimes referred to as the Lotus effect because leaves of the Lotus plant have this property.

Twist-o Gear Sphere

Hoberman Twist-O Spheres are no longer in production but are sometimes found on eBay.

From eBay: Search Now: Hoberman Twist-o

Here is a small version with the same geometry but with no gears:

From eBay: BUY NOW: Expand a Ball

Twist-O Gear Sphere: with 26 solid moving components connected by 48 rotating geared hinges this complex toy is a lesser known invention of the famous Chuck Hoberman. Like the regular Hoberman Sphere this engineered assembly of foldable linkages consists of rigid bars and geared hinges and is kinematically over constrained- the rotation of any hinge creates motion in all the joints and allows the sphere to collapse to a fraction of its extended size. On the market in 2003 but sadly no longer in production.

This toy inspired scientific research to create a new kind of engineered capsule called a “buckliball” that utlizes the phenomenon of buckling.

Penrose Tiling Puzzle

This puzzle was produced and sold in the 1990s. 
The individual tiles can be found on eBay (and sometimes the whole puzzle): 

From eBay: Search NOW Penrose Pentaplex Puzzle 
Wikipedia has the details on Penrose Tilings and their inventor Sir Roger Penrose 
A nice basic version of Penrose Tilings is available here: 
From Etsy: BUY NOW Penrose Tiles 

Penrose Tiling Puzzle: a challenging puzzle with pieces that come in only two shapes. The physicist and mathematician, Sir Roger Penrose, famous for his contributions to General Relativity, also discovered tessellations (tilings) that are aperiodic even though the two tile types are regularly shaped polygons. If one tries to shift a part of a Penrose tiling, the shifted part will not align or match up with any other part of the same tiling- all the way out to infinity! This puzzle, entitled “Perplexing Poultry”, uses polygons modified into crazy looking birds such that the tiles can only connect in specific ways to ensure the non-repetitive nature of the Penrose tiling structure. Shown here is one way these two tile types will fill the plane.

Sand Paperweight Toy

Available from these fine sources: 

From Amazon: BUY NOW Sand Globe Toys 

From Amazon: BUY NOW Sand Globe Toys: Winter Theme

A common version of this toy is for football fans: 
From eBay: BUY NOW Sand Football Paperweight Toy 

Wikipedia has a nice introduction to the amazing world of granular material science 

Sand Paperweight Toy: physics of granular materials- matter with unique properties between those of solids and liquids- as demonstrated with this simple toy. Granular materials, such as the sand in this toy, flow but also stack with a characteristic “angle of repose” as can be seen here as pyramid like ridges that form over the images of penguins.