Physics & Math Puzzles

Pearl Vault Puzzle

Get this puzzle here:

From Etsy: BUY NOW: Pearl Vault Puzzle

Pearl Vault Puzzle: a tetrahedron assembly of four identical pieces traps within a pearl. Three challenge aspects to this puzzle: 1) get the pearl out from the center, 2) explain the physics of how the disassembly occurs, and 3) reassemble- for which 3) might be the most challenging. Swipe for reveal and note the conservation of momentum aspect of the solution. Designed by Bruce Patterson and expertly produced by Pyrigan Puzzles. 

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 Threads

Available here:

From Crux: BUY NOW: Impossible Threads 

Impossible Threads: a classic project for learning machinist skills on a metal lathe where threads are made in the middle of a rod with solid ends- how then where the nuts placed on the threads? The ends are indeed the same piece of metal and where never detached. Swipe to reveal the method that takes advantage of how precisely metal can be machined. 

Flippe Puzzle Ball

Get this puzzle ball here:

From Etsy: BUY NOW: Flippe Puzzle Ball

Flippe Ball Puzzle: this ball is a puzzle that explodes and flies apart when spun. The puzzle is made of three identical pieces and a ball bearing which mysteriously locks the pieces together only to release them after a period of spinning. The main challenge is to fully explain why this spontaneous disassembly occurs. Swipe to see a slow motion boomerang loop of it coming apart- and how conservation of momentum has the three equal mass pieces on equally spaced trajectories (120°) with the ball bearing remaining stationary at the center. A product of puzzle master George Bell.

Bubble Trouble Puzzle

This hard to find puzzle is sometimes found here: 
From Bubble Puzzle

See more physics puzzles: featured physics puzzles

Bubble Trouble Puzzle: physics brain teaser- the trick here is to move all air bubbles to the center bulb. As with all puzzles featured here on @physicsfun, the solution relies on some fun basic physics principles- can you figure out which ones? Swipe to reveal solution.

Reverse Cartesian Diver

Glass divers available here: 
From Amazon: BUY NOW Glass Divers 

The reverse diver needs a bottle with a oval shaped cross section. I used the bottle from this product- it has the right shape and size and the label comes off easily: 
From Amazon: BUY NOW Oval Shaped Bottle Source 

Inexpensive and fun diver kits available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 

Wikipedia has the details on the Cartesian diver (and reverse diver)

Reverse Cartesian Diver: physics puzzle (swipe for hint). On the left is a Cartesian diver- pressing on the bottle forces water into the glass diver, which then compresses the bubble in diver’s head allowing it to sink. On the right is a reverse Cartesian diver- again the bottle is pinched but this time the diver ascends- why? 

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.

Ice Melt Demo

Get this similar demonstration kit here:
From Amazon: 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.

Rolling Uphill Illusion

Get the 3D print file here:

From Thingverse: Download Now: Uphill Illusion

Learn more: The amazing illusions of Kokichi Sugihara

See the many other Sugihara Illusions: in my collection

Rolling Uphill Illusion: the ball bearings seemingly roll uphill as if attracted by magnets of some kind. What’s going on? Swipe for reveal as it is truly a matter of perspective. A wonderful take on an illusion invented by Kokichi Sugihara of Meiji University. 3D printed by my good friend @zathras5 (Roger Key) from a file designed by Julian Hardy. 

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 Braid 

Get this nice example of mystery braid here:

From Art of Play: BUY NOW: Impossible Braid Key Fob

Here is a great video on how to make the mystery braid

See other Impossible Objects in my collection. 

Mystery Braid: challenge- how can three strands be braided if both sets of ends are connected? (swipe for reveal) A new addition to my collection of “impossible objects”, this leather key fob is braided from a single piece of leather, constructed by making two parallel slits but not cutting the ends. The solution is well known to those in the field of leatherwork- due to a twist of topology it’s possible to make this braid if the number of left strand over right crossings equals the times the right strand crosses over the left. Four strands braided this way is not mathematically possible, but 3, 5, or any odd number can be done!



Impossible Bolt

Only available from these aritist/craftsmen: 

From Art of Play: 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.

Doubly Impossible Bottle

Each constructed by hand, each a work of art-  get a personalized bottle here:

From The Bottleologist website: BUY NOW: Impossible Bottle with Frame

From his Etsy store: BUY NOW: Impossible Bottles

Doubly Impossible Bottle: the newest seemingly impossible object in my collection from craftsman/artist Grant Wicks @thebottleologist. An “impossible nail” object was somehow assembled within a Fannys Bay Whisky bottle- and personalized with my logo too! 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 inside. 

Pentominoes 3 Color Challenge

@physicsfun exclusive design- available only from STEMCell Science:

From Etsy: BUY NOW: 3 Color Pentominoes Puzzle

Pentominoes 3 Color Challenge: fit all 12 pentominoes into a 6x10 rectangle such that no two identically colored pieces touch. Pentominoes are the set of all 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 (there are 2339 ways to do this- yet even finding one solution is quite difficult). Adding the 3 color challenge reduces the number of possible solutions to just this one shown here! Made from laser cut acrylic and wood- and now available for the first time in a limited production run.

Mirror Vision Puzzle

More than three versions of this puzzle out there. Often available 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.