Physics & Math Puzzles

Impossible Knot

Follow the link below for full explanation and instructions. 
From mathematician/artist George Hart: Tying the Knot Puzzle 

Impossible Knot: how did this overhand knot get into this closed continuous band of rubber? It did not get there by cutting the loop, tying a knot, and rejoining it. Amazingly this band was once a rubber o-ring. How was it cut to produce a knot? An “impossible object” related to the Möbius strip by mathematician and artist George Hart- a brain teaser puzzle he calls “Tying the Knot”. 


Square Dissection Puzzles

Get these and other well made disection puzzles here:

From Etsy: BUY NOW: Square Dissection Puzzles

These puzzles are expertly laser cut and sold by GamesEfce. I spray-painted the pieces of mine to better show the shapes and relationships for the video. 

Square Dissection Puzzles: a square can be cut (dissected) into polygons and then reassembled into other regular polygons. Shown here: an equilateral triangle, a pentagon, and a hexagon. These are the record holders for smallest number of pieces needed: triangle (4 pieces by Henry Dudeney 1902), hexagon (5 pieces Paul Busschop 1870s) and pentagon (6 pieces Robert Brodie 1891). Fun fact- It is not known if any of these records are the smallest possible, no mathematical proofs yet exist on this question.

Anamorphic Harry Potter Puzzle

No longer in production but available on eBay: 

From eBay: BUY NOW: Harry Potter On Reflection Puzzle

Mirror Anamorphic Harry Potter: the conical mirror of the silver container reflects and reveals the distorted scenes in this 200 piece jigsaw puzzle of the famous wizard and school. The shape of the mirror allows for a mathematical operation, a type of affine transformation, to map the distorted image of the puzzle to the restored image reflected by the mirror. Real magic! 

Mirror Vision Puzzle

More than three versions of this puzzle out there. Get one here:

From eBay: BUY NOW: Mirror Vision Puzzle

Mirror Vision Puzzle: this Harry Potter themed puzzle has only 9 pieces but each supplies two parts of the final image- without the mirror one gets only half the picture. The top of each square is a corrugated lenticular composition of two images, and when viewed from the correct angle only one image can be seen directly, with the other reflected in the mirror, which combine in this case to reveal the famous phoenix bird of the HP stories. Flipping over the puzzle squares produces a second image to solve, this time a basilisk. An ingenious puzzle form from inventor/designer Mark Setteducati and sold by Mattel.

Nova Plexus Interlocking Puzzle

Precision machined and available in brass or stainless steel:

From Art of Play: BUY NOW: Nova Plexus Puzzle

Nova Plexus Puzzle: 12 identical brass rods can create 4 interlocking triangles in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 5 others that connect with it. Precision machined notches on the ends of the rods allow them to interlock with elastic tension such that vector sum of the 5 forces on each rod is zero- creating this astonishing geometry as the equilibrium state. Unlock the ends of any two rods and the system instantly disassembles (swipe to view process in slow motion). Invented/designed by artist and computer scientist Geoff Wyvill in 1978, this puzzle has just recently been made available for sale with a limited production run.

Impossible Dovetail

Inexpensive versions of this "impossible box" like that in the video avaiable here:

From Amazon: BUY NOW: Impossible Box Puzzle

Impossible Dovetail: this impossible object is pretty common, but it is a classic, and included in my collection. If one assumes a regular dovetail joint then this construction would indeed seem impossible without cutting and gluing, but what one sees from the sides makes for misleading assumptions as this box opens easily. Swipe for reveal once you’ve thought about about possible constructions. 

Impossible Bottle Sculpture Puzzle

Mr. Evans makes a variety of amazing impossible bottle sculptures: 
From Buy NOW Impossible Bottles by Philip Evans 

Nice Impossible bottles are often available on Etsy: 
From Etsy: 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. 

Impossible Nail

Nice versions are curretnly available from Etsy:

From Etsy: BUY NOW: Impossible Nail

Impossible Nail: An eighteen-penny nail driven through the inner notches of a solid piece of wood. The wood was notched and the nail added- no glue used or cuts made, and the nail is solid and in one piece. Not impossible, but creating this does depend on the use of some amazing physical properties of wood. I won’t reveal the method here but a quick search on YouTube produces a few how-to videos showing the process. 

Impossible Caged Golf Ball 

Some nice versions of this impossible object available here:

From Etsy: BUY NOW: Golf Ball in Wood Cage

See more of these thought puzzles in my collection here: Impossible Objects

Impossible Caged Golf Ball: Here a regular off-the-shelf golf ball is somehow trapped within a cage made from a solid piece of hardwood walnut. Neither the ball nor the wood were cut or glued in the fabrication process. The puzzle aspect is to consider how this object was produced (I have some theories- but I do not know the secrets of this artist).

Impossible Pipe Elbows

These are very hard to find- I had to make this one. Contact @physicsfun via DM if you really want one.

Many other types of impossible objects are avialable- see these links and videos: Impossible Objects

Impossible Pipe Elbows: made from standard pipe fittings held together only by their threads. No glue of any kind was used in its making. Design inspired by puzzle maker and artist Saul Bobroff.

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.

Dudeney's Dissection 3D Print

Get this set here!

From Etsy: BUY NOW: Dudeney's Dissection 3D Print

Dudeney's Dissection: an equilateral triangle canbe cut (dissected) into four pieces that will then assemble into a square. This 3D printed version comes as a puzzle- fit the pieces in each of two containers- a square and a triangle, which also makes it clear the two supplied shapes are of equal area. Fun fact: It is not known if a similar three piece dissection is possible. Also called Haberdasher's problem and described in 1907 by Henry Dudeney it is the only 4 piece solution known.

Trisected Cube

Get this puzzle here:
BUY NOW: Trisected Cube Puzzle

This puzzle came in my Curiosity Box subscrition. A great way to start collecting your own physics toys (and other brain food):
From the Vsauce team: BUY NOW: The Curiosity Box

Trisected Cube Puzzle: three identical pieces interlock to form a cube in this ingenious dissection puzzle. The cube is sliced following a helical path along a corner to corner diagonal, creating a smooth disassembly, and a smooth but surprisingly challenging initial reassembly. Invented by Robert Reid and designed by puzzle master Oskar van Deventer.


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! 

Uphill Roller

This set available here:

From Amazon: BUY NOW: Uphill Roller Double Cone

Uphill Roller: a double cone (like two funnels connect by their tops) will roll up a set of inclined rails. Although the bi-cone rolls toward the higher end, its center of mass descends due to the geometry of the rails. This curious construction was first published in 1694 by the noted surveyor William Leybourn to promote “recreation of diverse kinds” towards the “sublime sciences”. Physics fun from three centuries ago!

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).