Budget physics

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.

Mini Balance Pterosaur

Get similar prehistoric balance beasts here: 
From Amazon: BUY NOW Balance Pterosaur

Mini Balance Pterosaur: weights in the forward wing tips create a center of mass below this pterosaur's beak- making a system that can rotate and oscillate about a stable equilibrium condition. No magnets used or needed for this physics! Usually this toy is found in the form of a bird (direct dinosaur descendent). Pterosaurs are not dinosaurs, but are the largest animals to ever fly, and powered flight has only evolved four times: bats, birds, pterosaurs, and insects- in reverse order. 

Sphere Sticks Geometric Puzzle

Get this affordable and amazing puzzle here:

From Etsy: BUY NOW: Sphere Sticks

Sphere Sticks Puzzle: 30 identical wood pieces, each with two notches as shown, can create 12 interlocking pentagons in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 4 others that connect with it. Precision cut notches on the rods allow them to interlock with elastic tension such that vector sum of the 4 forces sum to zero in this tensegrity type equilibrium. The dodecahedron, with its 30 edges and 12 sides, is the basis of this puzzle sculpture. 

 


Photochromic UV Bracelets

Get this set here:
From eBay: BUY NOW: UV Color Change Bracelets

You may also want an awesome UV flashlight like this one:
From Amazon: BUY NOW: High Power UV Light

Check out this: Photochromic Frisbee

UV Color Changing Beads: the photochromic pigment molecules in the white beads actually change shape when struck by UV light, and the new shape alters their absorption properties such that they reflect brilliant colors. The color is temporary- when removed from UV exposure, room temperature thermal energy bumps the molecules back into their original configuration, and the color fades back to white in a few minutes. Here a UV flashlight reveals that each bracelet transforms to a different color. 

Cartesian Diver

Glass divers available here: 
From Amazon: BUY NOW Glass Divers or this complete set Cartesian Diver Kit

Inexpensive and fun diver kits to make in a bottle available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 
 

Cartesian Divers: increasing pressure on the water compresses the air bubbles in the small glass vials filling them further with water making them sink. Pascal's principle states that any change in pressure on an enclosed fluid (such as pushing on the rubber cover) is transmitted evenly to every part of the fluid- the physics of hydraulic brakes! Named after the physicist and philosopher Rene Descartes.

MaBoRun Minis

Many styles to choose from- get a MaBoRun here: 

From eBay: BUY NOW: MaBoRun Mini

Similar devices here:
From Amazon: BUY NOW MaBoRun Marble Run 

MaBoRun Minis: rolling marbles doing tricks as gravitational potential energy is converted to kinetic energy. Three mini marble runs each with a battery powered means of lifting the marbles: 1) a belt driven gear, 2) a scissor linkage that translates the rotation of the motor into linear motion to lift the marbles to the top and 3) an Archimedean Screw conveyer. Two of these runs incorporate a simulation of decaying orbits with conservation of angular momentum as the marbles whirl down funnel shaped tracks.


Pop Pop Boat

Get one here: 
From Educational Innovations: BUY NOW Pop-Pop Boat 
From Amazon: BUY NOW Pop-Pop Boats 

Wikipedia has the details on the physics and history of this little steamboat toy 

Pop-Pop Boat: birthday candle powered, super simple steam engine named after the sound it makes when operating. The engine is just a metal box, heated by the candle, with two pipes coming out of it. Steam builds up pushing water out with an explosive pop- which then creates a vacuum sucking more water in to repeat the process. Patented in 1915 these were very popular in the 1940's.


Homopolar Motor

Fairly simple to make- here are the inexpensive supplies needed to make a few of these motors. 
AA batteries have a diameter of 14.5 mm, so a bottom magnet with a diameter of 15 mm is just right: 
From eBay: BUY NOW Neodymium Disk Magnet 

Wire that looks and works well is just 10 gauge ground wire. Inexpensive and available at any local hardware store-- or order a small quantity here: 
From eBay: BUY NOW 10 gauge Copper Wire 

Wikipedia has some good details on the physics of homopolar motors 

Homopolar Motor: a minimalist electric motor- battery, wire, and magnet. This type of motor does not need a commutator- the polarity of the electromagnetic coil does not need to reverse. The challenge with this design is balancing the coil to center on the battery as it rotates. A favorite DIY physics toy!

Elastic Equilibrium Puzzle

Get this puzzle here:

From Amazon: BUY NOW: Atomic Cherry Puzzle

Elastic Equilibrium Puzzle: six spheres held together by three plastic springs. When assembled each sphere exerts the same force on its four neighboring spheres, producing this equilibrium state only if all six spheres are used to balance all the forces. A fun configuration to analyze in a 1st year physics course- the Atomic Cherry by Brainwright puzzles. 

Lissajous Roller 

Available from Pyrigan & Co.

From Etsy: BUY NOW: Lissajous Roller Illusion

Lissajous Roller: when viewing this 3D printed object from the side one sees a projection of a 3:2 Lissajous curve, but the object is actually cylindrical in frame and can roll towards or away from the viewer. When in motion a “dual axis illusion” is produced where the object appears to be rotating about a vertical axis. Invented by Bill Gosper and produced by Pyrigan & Co. 


Floating Yen

Aluminium 1 Yen coins are the perfect denisty to float as shown in the video:

From Etsy: BUY NOW: 1-Yen Coins

Floating Yen: the surface tension of water is strong enough to suspend the aluminum coin, and a trapped column of air in a second glass can submerge a portion of the surface with the coin. The 1-Yen coin has just the right mass and density for this demonstration. One of my favorite DIY physics demonstrations.


Magnetic Suspsension Sculpture

This DIY magneits sculpture can be assemebled with these parts.  Bring a magnet into a craft shop to find some necklace chain that is non-magnetic. 
From Amazon/eBay: BUY NOW: Quilting HoopNeodyumium Sphere Magnets

Magnetic Flux Gyroscope art and other amazing science inspired jewelry available here:
From Foxtail Jewelry: BUY NOW: Kinetic Magnetic Pendants
From Foxtail Jewelry: BUY NOW: Tabletop Magnetic Kinetic Art

Magnetic Suspension Sculpture: two neodymium magnets on chains suspended by their mutual magnetic attraction in this prototype kinetic sculpture (swipe to see scaled fine jewelry version by foxtailjewelry). These powerful magnets hold the chains taut with about a 2cm gap. Made from a quilting hoop where the magnets connect under their own force to steel nails soldered on to non-magnetic chain.

Wireframe Ambiguous Cube

Get the files (or order one printed) here:
From MakeAnything's MyMiniFactory: BUY NOW: Illusion Cube 3D Print Files
From Shapeways: BUY NOW: Ambiguous Cube Illusion

See the other illusions my collection: Ambiguous Objects

Wireframe Ambiguous Cube: another innovation of the ambiguous object illusion invented by mathematician Kokichi Sugihara of Meiji University- this time a 3D frame of a cube transforms to a cylinder! A new 3D print design from @make.anything

Poly acrylamide Polymer Vanishing Act

Get some of these grow-spheres here: 
From Educational Innovations: BUY NOW Growing Spheres 

Poly-acrylamide Polymer Vanishing Act: these spheres of hydrophilic polymer have an almost identical index of refraction as that of water- thus when submersed they become invisible. Note the elasticity of these spheres from the way they bounce, while at the same time they refract their surroundings as a spherical lens. The super absorbent spheres start as hard crystals with a radius of 2mm and grow to 11mm when immersed in water. So much physics going on here!