Budget physics

Rainbow Twirler

Get one here: 

From Amazon: BUY NOW: Rainbow Twirler

Rainbow Twirler: shaped by angular momentum and centripetal acceleration- when the speed of the ribbon is faster than the flicker fusion frequency of human vision it looks like a bubble. As the rotation speed increases the shape flattens- similar to the way the Earth bulges due to its rotation. Found this fun motorized base for this item in a toy store last week.

Acrylic Rattleback

These acrylic versions work great and are inexpensive: 

From STEMCell Science: BUY NOW: Rattlebacks  

Acrylic Rattleback: a favorite from my collection- prefers to spin counter clockwise. If spun clockwise, a complicated combination of friction, precession, and instability induced vibrations transforms the rotational energy into into rattling (energy of oscillations) and then into rotational energy in the opposite direction! This behavior is related to the asymmetric shape of the bottom of this kind of rattleback, it's somewhat propeller shaped with an "S" curve along the bottom ridge

Electric Motor/Generator

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.


Pop Pop Boat

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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.

Floating Rings Illusion

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.


Dudeney's Dissection 3D Print

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.

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.


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!

Sprial Oil Drop Timer

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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. 

 


Thermochromic Liquid Crystal Mood Necklace

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. 

Pearlescent Metallic Lava Lamp

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. 

Mini Waving Tube Guy

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.


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. 

 

Elastic Equilibrium Puzzle

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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. 

Simple Stirling Engine

Get this amazing model engine here:

From EngineDIY: BUY NOW: Simple Stilring Engine

See other featured DYI devices here: EngineDIY Models

Simple Stirling Engine: Perhaps the simplest piston engine ever devised- a single piston powered by a tiny alcohol lamp. Glass components allow a view of the internal workings of this design, and the interesting startup behavior from oscillation to full rotation. Heat engines produce mechanical motion from a difference in temperature- here the piston side is near room temperature (the central aluminum post is an excellent conductor and acts as a heat sink as the gas flows through), and the test tube is kept at high temperature via the flame, with metal fibers to help conduct the heat into the air (this component is called the regenerator). Swipe to see the elegant assembly of this model, and swipe again to see the engine power down. This external combustion design is attributed to Scottish engineer Robert Stirling back in 1816.