Amazingly this motor is available for less than $10 US.
From Amazon: BUY NOW: Brushless Motor/Generator with LED
Electric Motor/Generator: this inexpensive and common motor can also serve as a generator of AC electricity- here lightning an LED when the shaft of the rotor is spun by hand. Most electrical energy we use today is produced by moving a magnet near a coil of wire (known as Faraday’s law of induction) to produce an electric current. Removing the permanent magnet casing reveals this design to use 9 separate copper windings. I made a transparent second rotor with six neodymium magnets- and when these magnets are made to move near the windings the LED again lights with the flow of current. Swipe to see the beautiful magnetic field pattern of the rotor design using magneview film.
Get this high quality balancing bird here:
From Amazon: BUY NOW: Tipsy Metal Balance Bird
Brass Balance Bird: weighted wing tips create a center of mass below the bird's beak- making a system in stable equilibrium. No magnets! This bird and stand are made of steel with a polished brass finish- a work of art really- and useful too! (swipe to see)
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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.
Some assembley required and very inexpensively made- think "happy meal" type toy- available here:
From Amazon: BUY NOW: Solar Powered Ring Illusion
Floating Rings Illusion: powered by a photovoltaic (solar) cell and small motor the connected rings appear to be rolling in an improbable way. This version of this hard to find illusion is sold as an air freshener for the dashboard of your vehicle (seems a bit too distracting though)- perhaps better for a sunny window sill in the home. Fun physics and psychophysics in a very inexpensive plastic toy.
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.
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From Amazon: BUY NOW
Vortex II Coin Bank
Vortex II Coin Bank: interplay of potential energy of gravity and conservation of angular momentum- a simulation of a decaying orbit. Fun with every coin saved!
Get this fun cactus lamp here:
From Amazon: BUY NOW: Infinity Cactus Lamp
Infinity Cactus Lamp: parallel partially mirrored panes with green LEDs create the illusion of depth through the physics of reflection and refraction- in the shape of a saguaro!
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.
Get a set here:
From Educational Innovations: BUY NOW Newton's Yoyo
Newton Yo Yo: Newton's 3rd Law states that action force equals opposite reaction force- the the green and yellow spheres have equal mass, so the forces of the collision provide accelerations that are equal and opposite such that the spheres trade places.
Get this device here (in your choice of color):
From Etsy: BUY NOW: Dual Threaded Bolt Print
Dual Threaded Bolt: this 3D printed fidget toy illustrates an interesting design that may have important engineering applications in preventing loosening of fasteners. Here one nut threads on clockwise as normal- the other threads on counterclockwise on the same bolt.
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!
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From Amazon: BUY NOW: Oil Drop Timers
Spiral Oil Drop Timer: when this drop timer achieves its steady state the drops form with amazing regularity in terms of both the size of the drop and the spacing between drops. The physics of immiscible liquids, surface tension, viscosity, and gravity combine to produce these interesting patterns.
Similar mood jewelry available here:
From Etsy: BUY NOW Liquid crystal jewelry
Thermochromic Liquid Crystal “Mood” Necklace: heat from a hand brings out the temperature dependent color change of the liquid crystal. The molecules of the liquid crystal change orientation and spacing during the phase transition from liquid (warm) to crystal (cool). The molecular configuration shift allows for different diffraction effects producing the color shift.
Get this metallic lava version here:
From Amazon: BUY NOW: Metallic Lava Lamp
From explOratorium store: BUY NOW: Metallic Lava Lamp
See aslo: Magnetic Ferrofluid Lava Lamp
The Lava Lamp: with new pearlescent metallic “lava”- kinetic art with an amazing amount of physics on display: convective heat flow, Archimedes principle, surface tension (note how the smaller blobs form into spheres), and immiscible liquids to name just some of the science behind this famous device. In this loop one can see shock waves ripple through the blobs as they detach, and as they recombine at the bottom. Manufactured by Mathmos and invented in 1963 by Edward Walker of Dorset, England.
Get this inexpensive and silly toy here:
From Amazon: BUY NOW: Wacky Waving Inflatable Tube Guy
This power supply reccomended: BUY NOW: 9V power supply
Mini Waving Tube Guy: the physics of fluid dynamics describes the flopping behavior of the famous dancing tube guy. Bernoulli’s principle tells us that when air is moving with a velocity, the pressure in the region of the moving airmass is reduced. When the tube guy stands strait, air escapes through his head and arms allowing a temporary steady velocity of flow which reduces pressure inside and he collapses and bends. When the tube is bent, airflow is cut off, and the tube inflates like a balloon building pressure until air can again escape through the top- and the process cycles back and forth between these two states creating the iconic dance moves. This desktop version uses a 9V battery to power the fan.
Get one here!
From Educational Innovations: BUY NOW: WindGyro
WindGyro: Spin this top up with a puff of air! Small magnets keep the top secured to the base so that a stream of air will induce rotation as the air flows through the engineered turbine blades of the elegant spiral structure.
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.
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.