Budget physics

Photochromic Frisbee

Get this quality flying disk here:

From Amazon: BUY NOW: UV Chameleon by Discraft

You may also want a powerful UV flashlight:
From Amazon: BUY NOW: High Power UV Light

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Photochromic Frisbee: the plastic of the UV Chameleon by Discraft contains photochromic pigment molecules that actually change shape when struck by photons of UV light, and the new shape alters their absorption properties such that they reflect a deep purple color. The color is temporary- room temperature thermal energy bumps the molecules back into their original configuration, and the color fades back to white in about 3 minutes (shown here sped up x7). A long wave UV flashlight is used to “paint” the disk purple, and sunlight will do the same very quickly.

Rainbow Twirler

Get one here: 

From Amazon: BUY NOW: Rainbow Twirler

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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.

Rheoscopic Sworld

Get a Sworld ball (choose a color) here:

From Amazon: BUY NOW: Sworld Rheoscopic Ball

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Also- the best in rheoscopic kenitic art- see: the Vortex Dome

Rheoscopic Sworld: this nice example of fluid flow kinetic art uses rheoscopic fluid encased in flexible bubble of plastic to reveal the intricate motion of turbulence. A suspension of tiny flat mica crystals tend to align themselves at the boundaries where the fluid is moving comparatively faster or slower, making the typically invisible flow patterns visible. 


Sandscape Spontaneous Stratification 

Get this particular sand kinetic art here:

From Amazon: BUY NOW: Sandscape Kinetic Desk Toy

Click here for more amazing types of kinetic sand art. 

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Sandscape Spontaneous Stratification: a striking feature of this sand motion desk toy is the formation of striped layers. Typically pouring stuff together results in further mixing, yet here, when the sand mixture descends through a gap, the resulting pile is ordered into sorted layers. The larger rounded dark grains separate from the smaller sharp-edged white grains forming the layers you see here. The darker grains alone would stack into a steeper pile (larger angle of repose) than the white which would form a less steep pile. 

Balancing Dragon

The dragon version sometimes available here:

From Amazon: BUY NOW: Balance Dragon

Or get an extinct species here:

From Amazon: BUY NOW Balancing Pteranodon

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Balancing Dragon: weights in the wing tips create a center of mass below the dragon’s snout, making a system in stable equilibrium. Balanced here on the end of a bolt- no magnets used in this demo!

Moiré Kinetic Wheel

Get this device (and other variations) here:

From Amazon: BUY NOW: Moiré Fidget Device

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Moiré Kinetic Wheel: sold as a fidget toy this device has two plastic disks and each has a pattern of curved spokes that can rotate independently and produce interesting illusions of motion via moiré interference effects. Explore constructive and deconstructive interference patterns with this minimalist toy.


Missing Edge Piece Puzzle

Get this puzzle here:

From Etsy: BUY NOW: Missing Edge Puzzle Card

See the simiar and amazing: Matsuyama's Puzzle

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Missing Edge Piece Puzzle: fun math involved in the design of this puzzle, which illustrates how the concept of area can challenge our intuitions. Swipe to see the similar and amazing Matsuyama’s Paradox puzzle. A precision crafted puzzle by Jeux Efcé game shop. 

Happy/Sad Spheres

Get a set here: 

From Educational Innovations: BUY NOW: Happy/Sad Balls

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Happy/Sad Spheres: one ball bounces the other stops dead. The bouncy ball is made of neoprene rubber and exhibits high elasticity. The "sad" ball is made of polynorbornene and converts almost all kinetic energy into heat and sound- approximating/demonstrating the case of a completely inelastic collision. Polynorbrene is used in vehicle bumpers, for soundproofing, vibration damping, and other applications where recoil motion is unwanted.

Triple Pendulum Chaotic Fidget 

Get this chaotic fidget spinner here:

From Amazon: BUY NOW: Triple Pendulum Spinner

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Triple Pendulum Chaotic Fidget: This interesting spinner is made from stainless steel and features three physical pendulums each mounted with their own low friction bearing. In slow motion one can see the kinetic energy and angular momentum is transferred from one pendulum to another as the entire device rotates, with some spinning rapidly and others rotationally at rest- the intricacies chaotic motion, characterized by extreme sensitivity to initial starting conditions, tiny differences in how the system is released leads to dramatically different outcomes each time.


Floating Yen

Aluminium 1 Yen coins are the perfect denisty to float as shown in the video:

From Etsy: BUY NOW: 1-Yen Coins

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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.

Centripetal Kinetic Toy

This "iBall" desk toy is no longer in producltion. Howerver, a similar version of this toy can be made from these components:

From Amazon: BUY NOW: two piece acrylic shell

From Amazon: BUY NOW: 1/4 inch ball bearings

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Centripetal Kinetic Toy: seven rolling steel balls hug to the inside of the acrylic sphere given sufficient velocity. Here the balls are launched such that their orbits are in the same plane, and due to their angular momentum (and a torque due to gravity) the plane of rotation precesses like the axis of a spinning top until friction slows them down. This toy was made in 2007 (sadly no longer in production) and marketed under the name "iBall". 

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

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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.


Spinnobi Springy Spinner 

Get one here! 

From Amazon: BUY NOW: Spinnobi Spinner

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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 improved take on the spinner.

Drinking Dino Heat Engine

This dinosaur themed heat engine available here:

From Amazon: BUY NOW: Drinking T-rex Desk Toy

Get also: the related Drinking Bird Heat Engine 

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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! 

Animallusions Zebra

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.

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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

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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.

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

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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. 

Sphere Sticks Geometric Puzzle

Get this affordable and amazing puzzle here:

From Etsy: BUY NOW: Sphere Sticks

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Sphere Sticks Puzzle: 30 identical wood pieces, each with two notches as shown, can create 12 interlocking pentagons in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 4 others that connect with it. Precision cut notches on the rods allow them to interlock with elastic tension such that vector sum of the 4 forces sum to zero in this tensegrity type equilibrium. The dodecahedron, with its 30 edges and 12 sides, is the basis of this puzzle sculpture.