DIY

Diamagnetic Racetrack

Simiar diamagnetic levitation kits are available here: 
From eBay: BUY NOW Diamagnetic Levitation Kit

Diamagnetic Racetrack: thin pyrolytic graphite sheets levitate above powerful magnets. A set of five concentric neodymium magnets, alternating N-S-N-S-N comprise the racetrack and form the trapping field. Diamagnetic substances develop temporary repulsive magnetic fields only when they are in the presence of a magnetic field from some other source. Graphite of this sort is the most diamagnetic substance known.

Volta’s Hailstorm and Electrophorus

This inexpensive electrophorus set works great! 
From Amazon: BUY NOW Electrophorus Demonstration Set 
From eBay: BUY NOW: Electrophorus Demonstration Set

The container is just the middle part cut from a plastic water bottle, and the "hail" stones are Styrofoam craft beads: 
From Amazon: BUY NOW Styrofoam Craft Beads 

For Volta's Hailstorm to work, the beads must be coated with a conducting spray (here is what I used): 
From Amazon: BUY NOW Staticide Spray 

Wikipedia has a very nice description of the physics of the Electrophorus and how it is used to transfer electric charge. 

Volta’s Hailstorm and Electrophorus: electrical forces due to electrostatic charge send foam beads flying in this version of the historic demonstration by physicist Alessandro Volta. The beads are covered with an electrically conductive coating allowing them to transfer charge from the environment to the plate of the electrophorus. The acrylic platform becomes negatively charged when rubbed with a paper napkin, but it is also an insulator so the charge on it can not flow on to the aluminum plate of the electrophorus. Instead the charge on the platform pushes electrons to the top of the plate (like signs repel) and touching the plate results in a spark that removes the electrons giving the plate a significant positive charge that will then attract the beads. 

Popsicle Stick Bomb

Craft sticke work great:

From Amazon: BUY NOW: Stick Bomb Supplies

Amazingly: There is a Wikipedia entry on Stick Bombs and their physics

Popsicle Stick Bomb: a form of simple tensegrity, the elastic potential energy of the bent sticks is dramatically released under application of a slight concussive force such as an impact with a table top- shown here in forward and backward slow motion (swipe to see three more explosions). Shown here is one of the simplest constructions with 5 flat sticks woven into a spring-loaded configuration held in place by friction and tension induced by the bending of the wood. A nice demonstration of energy conversion- potential to kinetic.


Hoberman Actuator with Sphere

The Actuator mechanism is out of production but can still be found on eBay, comes with power supply, Expandagon kit, and connecotors that snap on to a Hoberman Spjere. 
From eBay: BUY NOW: Hoberman Actuator

The spheres are still in production and come in various sizes and colors: 
From Amazon: BUY NOW Hoberman Spheres 

Hoberman Actuator with Sphere: This actuator mechanism creates kinetic art out of a Hoberman sphere, designed to smoothly expand and contract the isokinentic structure. The Hoberman sphere itself is a special assembly of foldable linkages consisting of rigid bars and simple hinges is kinematically over constrained- motion can only occur along the radial direction and the movement of any hinge creates motion in all the joints. The engineering and physics behind deployable space structures!

The Orb Drop IV

A new KickStarter campaign from engineer and maker extraordinaire Rian Suiter. Rian has delivered on each all 11 (eleven!) of his creative physics toy related KickStarter campaigns to date. Check out his latest here: 
From KickStarter: Order NOW Orb Drop IV marble run track 

The Orb Drop IV: @orbdrop has created another fun DIY marble run- this one uses an Archimedean screw mechanism to bring the marbles continuously back to the top where they are launched along one of three paths- including a vortex funnel. Gravitational potential energy is transformed to the kinetic energy of the orbs as they loop and negotiate the banked turns of the snaking tracks. Three AA batteries and a small motor power the transport assembly. 

Super Absorbent Polymer

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

Super Absorbent Polymer: poly-acrylamide polymer crystals are able to absorb up to 200 times their volume of water. Here seven small spheres, approximately 4mm in diameter, were immersed in water for three hours, after which they were slightly more than 23mm across. The final gel sphere is more than 99.5% water- and they bounce! 


Frabjous Geometric Sculpture Puzzle

Get one here- five colors to choose from:

From MoMath: BUY NOW: Frabjous Sculpture Puzzle

Frabjous Geometric Sculpture Puzzle: 30 identical laser cut acrylic pieces interlock into 12 interconnected five point stars (each with a spiral vortex center) in this puzzle based of the Frabjous sculpture by artist and professor of mathematics George Hart (Prof. Hart is now on Instagram, follow him at @george.hart.sculptor to see more of his amazing work.) Note that if one connects the tips of the stars one gets the outline of a dodecahedron, with its 30 edges and 12 sides, and if one considers the face planes of the linked pentagrams the underlying shape is a polyhedron called the “great rhombic triacontahedron”. A year or so ago I got to visit the National Museum of Mathematics in NYC where I bought this puzzle in the @momath1 museum shop. This puzzle was great fun to assemble- buy one to support this inspirational museum, and make a great sculpture for your bookshelf! 

Vibration Unthreading

Get inexpensive small motors and accesories for DIY projects here:
From Amazon: BUY NOW DC Motors Kit

A DIY project to see if just shaking a bolt at the right frequency could make a standard nut rotate and fall off. Similar physics to the phase locking propeller toy featured in my last post. Motivated by videos seen on Instagram where a brass bolt is placed in magnetic putty and the nut mysteriously rotates up and off- now convinced that vibration is how that effect is produced. Here a small DC motor spins an offset mass to produce the vibrations.

3D Print Planetary Gearset

Similar 3D prints available as fidget toys here:

From Etsy: BUY NOW: Gear Spinner Fidget Toy

Or print it yourself! (.stl files are available here):
From Thingverse:
Emmett Lalish Download: Gear Bearing 
Refined version featured here by Don Stewart Download: Honeycomb Gear Bearing 

3D Print Planetary Gearset: amazingly this gear set is printed assembled, with interlocking herringbone teeth. The gears will not come apart, in fact this design can only be accomplished by 3D printing the gears interlocked with each other. Designed and first printed by Emmett Lalish in 2013, and this version with refined precision and honeycomb by Don Stewart. 


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.

Floating Rings Illusion: Dr. Manhattan Booth

Created in my shop with these parts:

From Amazon: plastic rings, plastic sphere, blue paint

Inspired by the Phone Booths in the new Watchmen series.

Calling Dr. Manhattan: floating rings illusion device inspired by the recent Watchmen series. Two attached rings appear to roll in an impossible way around an orb, featured in a number of scenes on top of blue interplanetary phone booths in the new Watchmen series. Created in my shop with plastic rings and some blue spray paint.