### Two Marble Puzzle

Another version of this puzzle available here:

From Etsy: **BUY NOW Two Marble Puzzle **

From Amazon:** BUY NOW: Two Marble Puzzle, **or get this** set of puzzles**

Two Marble Puzzle: physics brain teaser- move both marbles to their top locations on each side simultaneously. The solution to this puzzle relies on some fun basic physics principles- can you figure out which ones? Swipe to reveal solution. Found this well made version of this classic physics puzzle at a gift shop in San Francisco (note Golden Gate Bridge motif).

### Raketti Puzzle

Get one here:

From Amazon: **BUY NOW Raketti Physics Puzzle **

From eBay: **BUY NOW Raketti Physics Brain Teaser **

Raketti Puzzle: physics brain teaser- the challenge is to remove the cone topped cylinder from the hole without touching the bottom container. It can be done in a matter of seconds! The solution to this puzzle (like others featured here) relies on some fun physics principles. Answer below and swipe to reveal solution.

### 10 Hex Puzzle

This and other beautiful and well made puzzles are available on Etsy:

From Etsy: **BUY NOW 10 Hex Puzzle **

Two great resources about these polyhexs: polyform puzzler page and puzzleworld page

10 Hex Puzzle: this puzzle is comprised of pieces which are the set of all ways three and four hexagons can be joined with a common edge. There are 3 trihexs and 7 possible tetrahexs, and similar to pentominoes, these 10 polyhexs can assemble into a large hexagon. Amazingly there are exactly 12,290 solutions to this puzzle- but it’s still a challenge to find just one!

### 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 ?

### Four Marble Puzzle

Get this well crafted puzzle from Creative Crafthouse here:

From Amazon: **BUY NOW Crossroads Four Marble Puzzle **

From Etsy: **BUY NOW Four Marble Puzzle **

Four Marble Puzzle: physics brain teaser- move all four marbles to their corner locations simultaneously. Each slot slopes down towards the center such that the marbles tend to stay at the center- so, how would one get them to roll outward at the same time? The solution to this puzzle (like others featured here) relies on some fun basic physics principles. Answer below and swipe to reveal solution. A beautiful and well-made puzzle from Creative Crafthouse.

### 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.

### TrueBalance

Get the full version (8 disks made of wood) or the mini (6 disks, blue or red plastic):

From Amazon: **BUY NOW TrueBalance Coordination Puzzle **

TrueBalance: coordination challenge puzzle- get the six disks, connected by bearing swivels, into a vertical stack by only tilting the handle. Harder than it looks to get each disk’s center of mass above the one below at the same time into the unstable equilibrium final state. The swivels constrain the system, limiting the degrees of freedom, and allowing strange and interesting motion. Kinetic art as a toy!

### Shashibo: Cube to Rhombic Docecahedron

**ORDER HERE : **Shashibo Geometric Art

Shashibo Transformations: a rhombic dodecahedron transforms into a cube- two possible configurations of this amazing dissection puzzle. The Shashibo is a cube cut into 12 equal irregular tetrahedra- these pieces are connected symmetrically with hinges, and 36 hidden magnets then allow more that 70 stable and geometrically interesting configurations to be discovered- swipe to see few more.

### Impossible Bottle Sculpture Puzzle

Mr. Evans makes a variety of amazing impossible bottle sculptures:

From impossiblebottle.co.uk: **Buy NOW Impossible Bottles by Philip Evans **

Impossible bottles are often available on eBay:

From eBay:** BUY NOW Impossible Bottles**

Impossible Bottle Sculpture Puzzle: seemingly impossible, but created with clever engineering, this “impossible” bottle contains a padlock and full deck of cards still in the wrapper (a cut out in the side of the box reveals that all the cards are inside). The puzzle aspect is to consider how the bottle was produced (I personally have some theories- but I do not know the secrets of this artist). I can tell you with high certainty that the bottle was never cut or altered in anyway, and it was not somehow formed around the objects. This bottle by Phil Evans is one of the best I’ve seen.

### 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.

### Pentominoes

Get this set here:

From Etsy: **BUY NOW Hardwood Pentominoes **

Many versions available here:

From Amazon:** BUY NOW Pentominoes **

Pentominoes: the 12 possible arrangements of five identical squares joined edge to edge. Since 5x12=60, the pentominoes can tile a 6 x 10 rectangle with no gaps (2339 ways to do this- yet even finding one solution is a challenge). I love this beautiful set from artist/woodworker Ron Moore where each pentomino is made from a different kind of hard wood.

### Poly Density Puzzle

Get the kit here:

From Educational Innovations: **BUY NOW Polydensity Bottle Kit **

Poly Density Puzzle: my favorite science brain teaser- white beads and blue beads "float" oddly separated beneath the surface of a clear liquid. If the contents are mixed by shaking the container, the white beads gather at the top and the blue sink to bottom! Adding to the mystery; after about 30 seconds the two layers of beads will have slowly moved back to the middle. What is your guess as to the physics behind this behavior?

### Cylindrical Lens Puzzle

A similar puzzle (but taking advantage of horizontal symmetry) available here:

From Educational Innovations: **BUY NOW Cylindrical Lens Puzzle **

Cylindrical Lens Puzzle: this cylinder of acrylic acts as lens that focuses light along a line rather than a point- and thus it can invert an image along its symmetry axis. Puzzle question: the word "GREEN" is flipped by this lens but the word "TOMATO" seems unaffected. Is the physics significantly different for red wavelengths as compare to green? Or is there another explanation/trick? Answer below.

### Magic Sand Wand Puzzle

This puzzle was purchased in the 1990s, check back in a week or so as I hope to provide a source for these sand wand puzzles. Meanwhile, please see the next links and videos for other amazing physics puzzles you can own.

Wikipedia has a good introduction to the possible mechanisms of the Brazil nut effect

Magic Sand Wand Puzzle: this week’s physics brain teaser- move the steel ball through the sand to the other end of the tube. Amazingly it can be done in less than 6 seconds! Hint: spinning won’t help this time. The solution to this vintage puzzle relies on some interesting physics concerning granular convection. Answer below and swipe to reveal solution.

### Ice Melt Demo

Get this similar demonstration kit here:

From Educational Innovations: ** BUY NOW**

Ice Blocks Melt Demo

Ice Melt Demonstration: Wood or Aluminum- which will melt the ice fastest and why? Both blocks start at the same temperature (room temp) and have the same shape and volume. Swipe to reveal result shown in real time (not sped up!) Hint: Although both blocks are at the same temperature, the aluminum feels cool to the touch and the wood block feels warm. Those who have taken basic physics should have an advantage on this question- one block is an excellent insulator and the other a conductor.

### Tessellating Geckos

These laser cut hardwood geckos are available here:

From Etsy:** BUY NOW Tessellating Geckos **

Tessellating Geckos: MC Escher inspired lizard cutouts interlock precisely to tile a surface with no overlaps or gaps. Laser cut from maple, walnut, and cherry wood by maker/artist Craig Caesar and inspired by MC Escher’s “Study of Regular Division of a Plane with Reptiles” 1939. G4G week: Martin Gardner wrote about the art and math of Escher in 1961- which helped create the popularity that his work has experienced ever since.