DIY

Curie Point Heat Engine

This DIY project is pretty easy to build. One half of one of these inexpensive magnetic necklace clasps will work well for the heated magnet. 
From Amazon: BUY NOW: magnets for curie point engine

A full engine is available from my friends at Grand Illusions Ltd: 
From GI LTD: BUY NOW: Curie Engine 

Curie Point Heat Engine: when the magnet on the end of the wire heats up to a particular temperature (the Curie point) its magnetic field is temporarily lost until it cools. This engine design uses a second magnet to pull the swinging magnet back into the heat source once the magnetic field is reestablished. Repetition of this process creates mechanical motion as long as the heat source is fueled.

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. 

Hyperbolic Holes

This inexpensive kit available here:

From Amazon: BUY NOW: Hyperbolic Holes Kit

Hyperbolic Holes: a straight rod, in this case a pencil, glides through a symmetrical pair of curved holes. The design is based on the hyperboloid, the 3D ruled surface traced by an offset rotating diagonal line. This device is sold as an inexpensive kit to assemble yourself, and includes a motor with geared drive and pre-cut pieces. The pencil is my addition- sharpened to just the right size to clear the curved openings.


Self Propelled Homopolar Motor

Here are disk magnets I used for the "wheels": 
From eBay: BUY NOW Neodymium Disk Magnets 
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 

Self Propelled Homopolar Motor: cylindrical neodymium magnets supply the static magnetic field for this motor and become the wheels of a very simple vehicle with an AA battery as the energy source. As soon as both ends of the copper wire make contact, an electric current will flow which in turn induces a magnetic field around the wire. This induced field around the copper wire will then interact with the neodymium magnets on each end causing them to spin- a wonderful example of a motor with minimal components.

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!

Centripetal Spheres

Just thread a rubber band through two of these drilled steel balls and you are ready to go! 
From Amazon: BUY NOW 
Drilled Spheres 

Centripetal Spheres: two ball bearings connected by a rubber band orbit each other as energy oscillates between elastic potential energy and rotation kinetic energy. Just wind up the rubber band and let go. When the rubber band has unwound the rotational inertia of the bearings winds it back up until it changes direction. The process repeats until the initial energy is dissipated through friction.


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!

Glow Trace Chaotic Pendulum Kit

Get this super nice, affordable, and fun to assemble kit here:
From KiwiCo: BUY NOW: Glow Pendulum Kit

Get amazing quatilty science kits delievered to your home- this glow pendulum is part of the Tinker Crate subscription. 
From KiwiCo: LEARN MORE: Tinker Crate Subscription

Glow Trace Chaotic Pendulum: this fun and amazing DIY kit features a UV diode to trace the intricate path of this double pendulum system on to a phosphorescent screen, revealing the physics of chaotic motion. It’s amazing that such complex motion can arise from a simple assembly of two pendulums, one attached to the end of the other. Chaotic motion, such as that observed here, is characterized by extreme sensitivity to initial starting conditions, tiny differences in how the system is released leads to dramatically different outcomes each time. 

 

Electromagnetic Levitation Module

Get this kit here (comes complete as shown in my video):
From engineDIY: BUY NOW: Magnetic Levitation Module

The featured sculture is by Bathsheba Grossman, affordable and beautiful math art available here:
From Etsy: BUY NOW: Soliton Sculpture

Electromagnetic Levitation Module: this engineered control system uses adjustable electromagnets (four copper coils) and and two Hall effect magnetic field sensors (held firm embedded in white silicone) to levitate an 5cm diameter neodymium magnet platform about 3 cm in mid-air. A feedback loop informed by the Hall effect sensors allows fine tuning of the magnetic field to exactly balance the pull of gravity, and is powered by a standard USB connection. The platform also rotates, perfect for showcasing one of my metal 3D printed mathematical sculptures by Bathsheba Grossman.


The FluoroSphere

The kit includes the UV LED base, elegant glass sphere, and enough fluorescent gel for many repeat lights shows. 

From PyroFarms: BUY NOW: FluoroSphere

From Amazon: BUY NOW: FluoroSphere

The FluoroSphere: intricate and dynamic lights shows are produced within an elegant glass sphere as fluorescent dyes in mineral oil slowly mix into room temperature water. Ultraviolet LEDs (in the base on which the sphere rests) make the dyes glow brightly and reveal the initial nondiffusive mixing structure which includes the phenomena of drops, plumes, and other features of Rayleigh-Taylor instabilities. Shown here, slightly sped up, is the first 8 minutes or so of the process which takes up to half an hour to mix evenly. The green light is characteristic of the famous fluorescein dye.

 

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!