Recent Posts

Rhombic Blocks Mathematical Puzzle

This beautifully made puzzle available here:: 
From Etsy: BUY NOW Rhombic Blocks 

Rhombic Blocks Mathematical Puzzle: There are 9 possible ways three rhombuses can be joined together along a common edge, and similar to pentominoes, these 9 tri-rhombs can tile a polyhedron, in this case a hexagon. There are 14 solutions to this puzzle, and one where no same-colored pieces touch. A beautiful math discovery by puzzle master Stuart Coffin.

Memory Spring

Available here: 
From Mindsets: BUY NOW 
Memory Springs 

Affordable samples and kits here:
From Educational Innovations: BUY NOW: Energy Wire 

Similar produces featuring Nitinol Memory Wire: 
From Amazon: BUY NOW 
Nitinol Memory Wire Kits 

Memory Spring: some special alloys of brass can be made to have a shape memory triggered by temperature. These springs quickly change their length from 1 cm to 2.5cm when heated above 90 C (done here with hot water) and just as quickly shrink back to original size when cooled (immersed in cold water). Useful in many applications, especially things like automatic fire sprinkler valves and thermostats in car engines. This amazing property is related to a solid state phase transition similar to that of Nitinol wire called a Martensitic transformation.


Holoscopes

Order a holoscope from the artist's gallery here: 
The artwork of Gary Allison: BUY NOW Holoscopeworld.com 

6 and 12 Faced Holoscopes: a cube and dodecahedron of mirrors. A type of kaleidoscope based on truncated Platonic solids by artist Gary Allison @holoscope2000. These holoscopes are in the form of two famous Platonic solids- each with all the corners cut off to allow light to enter through triangular holes. Through the symmetry of the reflections, these triangles appear as an infinite array of tetrahedron shapes in the dodecahedron, and as beautiful repeating stellated octahedrons in the cube. Each holoscope has stained glass on the exterior and front surface mirrors on the inside which create the amazing and seemingly impossible spaces within. 

Corner Cube Prism

Retroreflectors available here: 
From eBay: BUY NOW 
Corner Cube Reflector


-and a inexpensive UV laser pointer here: 
From eBay: BUY NOW 
405nm Laser Pointer

Corner Cube Prism: a light ray entering a mirrored retro-reflecting prism always exits along a parallel path. The complete path in the prism can be seen with a 405nm UV laser beam which is made visible via fluorescence of dopant chemicals (such as Pb, Mn, and Zn) often added to create optical glass. The geometry of a trihedral retroreflector is simply the corner of a cube! Arrays of corner-cubes like this one were placed on the Moon by Apollo astronauts to allowing precise measurement of the Earth-Moon distance by bouncing powerful laser pulses back to Earth observatories.

The ΦTop

Professor Brecher has a limited supply of these "golden" (brass) versions of this top available on Etsy 
From Etsy: BUY NOW PhiTOP in Brass 

Aluminum version available here:
From Amazon: BUY NOW phiTOP 

The ΦTop - Golden Version: spinning things have surprising physics! This unique top is made of solid brass in the shape of a prolate elIipsoid- and the name of the top is derived from the following design requirement: the ratio of the semi minor (short) axis to the semi major (long) axis is made equal to the mathematical constant the golden ratio φ (phi). Invented by astrophysicist Kenneth Brecher, this top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top. The concave mirror keeps the top from wandering off and the glass surface has minimal friction allowing the top to spin for a long time- this video shows various stages of 8 minutes of total spin time.


Primed Siphon

Available here: 
From Shapeways: BUY NOW 
Primed Siphon Arch

Primed Siphon: liquid moves until the water levels are equal- curious combination of the effects of gravity, molecular cohesion, and atmospheric pressure. The tube is hollow and pre-filled with water, and the spherical shells on each end are cups also full of water. With each end of the tube submerged into each cup, atmospheric pressure holds the water in the tube until the siphon can be placed to connect the glasses.