This inexpensive kit available here: From eBay: 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- just the right size to clear the curved openings.
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.
These inexpensive test cards are available here:
From eBay: BUY NOW
Polarization Test Cards
Get some polarizing filter sheets here:
From Amazon: BUY NOW Polarizing Sheets
Explore many aspects of polarization with this kit:
From Educational Innovations: BUY NOW Polarizing Filter Demo Kit
See this short introduction to linear polarizing filters on Hyperphysics, and many more details on polarization from Wikipedia.
Polarization Test Card: light has features that are invisible to the human eye, such as the orientation of its electric field (denoted as polarization), but can be revealed to us by a polarizing filter, used to block light with specific polarization orientations. Inexpensive test cards like this are often found in shops selling polarized sunglasses. The molecular structure of plastics can rotate the polarization of any light that passes through, and this card has such thin layers added to the top of the photo to create the hidden silhouettes seen here.
Available in a variety of styles:
From eBay: BUY NOW Magnetic Top and Snake
From Amazon: BUY NOW Magnetic Top and Snake
Magnetic Top and Snake: the magnetic tipped top stays on the perimeter of the steel snake (or is it a planarian?)- but since the top has much more mass, the snake moves the most slithering to and fro. This kinetic art toy has been around for decades and takes advantage of Newton's 3rd law and rotational kinetic energy.
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.
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 illusion here:
from Amazon: BUY NOW: Animallusions Zebra
or here: Illusion Animals
The original DIY dragon from G4G 3: Dragon.pdf
Animallusions Zebra: an amazing version of the hollow face illusion where the zebra’s head appears animated, and gives the impression that it’s always looking in the direction of the viewer. This zebra seems inspired by the dragon illusion created for the 1998 Gathering for Gardner by the Binary Arts Corporation of Bill Ritchie et al. Some fun physics of perspective and psychophysics for your shelf.
From Amazon: BUY NOW
Metal Balance Bird and Stand
From eBay: BUY NOW
Metal Balance Bird and Stand
Metal Balance Bird: weights in the wing tips create a center of mass below the bird's beak- making a system in stable equilibrium. No magnets! This is the nicest version of this toy I’ve seen- with bird and iconic stand cast in zinc alloy metal.
Get a set here:
From eBay: BUY NOW Tornado Spheres
Get a concave mirror like the one in the video for less than $3 here:
From Amazon: BUY NOW Concave Mirror
And get a set of inexpensive colored lights here:
From eBay: BUY NOW Color LED lights
Tornado Spheres: two ball bearings welded together can be made to spin up to 2000+ rpm by the Magnus Effect using a stream of air. Shining three colored LEDs on the spinning pair produces an illusion of floating rings along with a second illusion that these rings are rotating and changing direction due to aliasing with the frame rate of the video camera (like the famous wagon-wheel effect).
This dinosaur themed heat engine available here:
From Amazon: BUY NOW: Drinking Trex Desk Toy
Get also: the related Drinking Bird Heat Engine
Drinking Dino Heat Engine: So what physics presents did you get this year? I got this Dippy Dino heat engine- where cooling by evaporation at the head leads to lower pressure in the top bulb such that the dichloromethane fluid (colored green) rises up the neck making the T-Rex top heavy and the dino tips over dipping its face in the water and letting the fluid return to the bottom bulb. The process repeats as long as the top stays wet. A fun and silly variation on the famous drinking bird physics toy- and the T-Rex was a closely related ancestor to the dinosaurs that live today- birds!
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.
Similar devices available here:
From Educational Innovations: BUY NOW Mirascope
From Amazon: BUY NOW Mirascope
Mirascope: two parabolic mirrors create a 3D image above the actual object. A repost of one of my favorite physics toys ever. The image of the dice made here is not a hologram and is produced solely by reflection of light rays between special concave mirrors. Discovered circa 1969 by Landry and Elings at UC Santa Barbara.
Get one here!
From Amazon: BUY NOW: Spinnobi Spinner
Spinnobi: a spinner with bounce! With springs mounted along the axis on both sides of the dense rotating silicone disk, this spinner demonstrates gyroscopic stability- keeping its orientation as it falls and bounces. Conservation of angular momentum on display with this new take on the spinner.
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.
These aluminium 1 Yen coins are the perfect denisty to float as shown in the video:
From Etsy: BUY NOW: 1-Yen Coins (20)
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.
This device is sold as the "Static Shocker" hands on lab. Get one here for $8.95! :
From Educational Innovations: BUY NOW Static Shocker Mini Van de Graaff
The device can use an empty aluminum can for the top electrode which works- but this $9 hollow steel sphere looks and works even better- I used the 80mm sphere:
From eBay: BUY NOW Hollow Steel Sphere
Van de Graaff Generator: this miniature electrostatic generator can create potentials of more than 50,000 volts allowing sparks to jump a couple centimeters through dry air. Similar physics to the sparks created when shoes scuff on carpet, a moving rubber dielectric belt carries electrons away from the top sphere leaving it positive charged- as can be seen by the electrostatic repulsion of some Mylar strands. A small battery powered 3V motor drives the belt via the bottom pulley in this unit that costs less than $10 US.?With appreciation to @educational_innovations for sending me this device!
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 mirror-image pair here:
From curiositybox.com: BUY NOW: Enantiomorphic Rattlebacks
Enantiomorphic Rattleback Pair: one reverses to always spin clockwise, the other reverses to spin counter-clockwise. This behavior is related to the asymmetric shape of the bottom of this kind of rattleback, each is somewhat propeller shaped with an "S" curve along the bottom ridge. This pair are mirror images of each other (enantiomorphs) in terms of shape. When set to spin a reversal can take place due to a complicated combination of friction, precession, and instability induced vibrations which will transform the rotational energy into into rattling (energy of oscillations) and then into rotational energy in the opposite direction! Thanks to team Vsauce for bringing this set into existence.