Budget physics

Magnetic Top and Snake

Available in a variety of styles: 
From eBay: 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. 

Oil Drop Timer

Get one here: 
From Amazon: BUY NOW Dolphin Timer 

Oil Drop Timer with Dolphins: immiscible fluids of different densities stay separate under gravity with the lightest density on top. The density of the plastic dolphins is greater than the density of the top fluid but less than the density of the bottom fluid, so they stay at the boundary in equilibrium. The dolphins have a metal weight in their tails so that the buoyant force will keep them upright even as the liquids trade places (2 minutes shown in time-lapse). Archimedes' Principal at work here at multiple levels. 

Pixelated Playing Cards

Available from these fine sources: 
From Amazon: BUY NOW Pixel Cards 
From eBay: BUY NOW Pixel Cards

Pixelated Playing Cards: what one sees is all about the lighting with this transparent deck of cards. When backlit these poker sized cards become simply a grid of dots- reminding us that what we see not only concerns the physical properties of the perceived object, but also the location of the light source and the frequency and intensity of its emissions.


Time's Up

Similar timers available from these sources: 
From eBay: BUY NOW 
Inverted Timer 


From Amazon: BUY NOW 
Inverted Timer 


Time's Up: inverse of the sandglass- tiny plastic beads are less dense than the water and thus ascend to the top of the container under the influence of a buoyant force in accordance with Archimedes' principle. This timer takes almost exactly 6 minutes to complete shown here at normal speed for the first half of this video, and the second half is condensed to 24 seconds in time-lapse. 

Van de Graaff Generator

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! 


Self-Propelled Homopolar Motor on Aluminum Foil Racetrack

I used neodymium disk magnets, small end = 1/2" diameter, Large end = 3/4" diameter. 
From eBay: BUY NOW Disk Magnets for Simple Motor 

Foil Runner Motor assembly diagram: 
Self-Propelled Homopolar Motor on Aluminum Foil Racetrack: A favorite DIY physics toy where disk shaped neodymium magnets supply the static magnetic field for this motor and become the wheels of a very simple vehicle with an AAA battery as the energy source. As soon as both ends make contact with the conducting aluminium foil an electric current will flow which in turn induces a magnetic field underneath the battery assembly. This induced field will then interact with the neodymium magnets on each end causing them to spin- a wonderful example of a motor with minimal components. The racetrack is a cardboard circle from a pizza box covered in kitchen foil.

Hydrophobic Water Maze

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.

Backflipping Wind-Up

Get a Back Flip wind-up toy here:

from eBay: BUY NOW: Uglydoll Backflipping Toy

from Amazon: BUY NOW: Backflipping Wind Up Toys

Backflipping Wind Up: an energy transfer toy- a wound coil spring transfers and stores energy through a set of gears to a straight spring which is suddenly released to create kinetic energy which is then converted to gravitational potential energy- sending the toy air bound into a back flip. Here the Uglydoll character Is made of clear plastic allowing the internal mechanism to be visible. In addition the feet of the character must push off with just the right rotation rate to allow for one full rotation in the air, and the tail has a foam pad to absorb the impact and stop the rotation. A lot of fun physics to consider in this toy.

 


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.

Magnetic Suspsension Sculpture

This DIY magneits sculpture can be assemebled with these parts.  Bring a magnet into a craft shop to find some necklace chain that is non-magnetic. 

From Amazon/eBay: BUY NOW: Quilting HoopNeodyumium Sphere Magnets

Magnetic Suspension Sculpture: two neodymium magnets on chains suspended by their mutual magnetic attraction in this prototype kinetic sculpture. These powerful magnets hold the chains taut with about a 2cm gap. Made from a quilting hoop where the magnets connect under their own force to steel nails soldered on to non-magnetic chain.

Mini Balance Pterosaur

Get similar prehistoric balance beasts here: 
From Amazon: BUY NOW Balance Pterosaur

Mini Balance Pterosaur: weights in the forward wing tips create a center of mass below this pterosaur's beak- making a system that can rotate and oscillate about a stable equilibrium condition. No magnets used or needed for this physics! Usually this toy is found in the form of a bird (direct dinosaur descendent). Pterosaurs are not dinosaurs, but are the largest animals to ever fly, and powered flight has only evolved four times: bats, birds, pterosaurs, and insects- in reverse order. 


Sphere Sticks Geometric Puzzle

Get this affordable and amazing puzzle here:

From Etsy: BUY NOW: Sphere Sticks

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. 

 

@physicsfun Rattleback

Availble from STEMCell Science:

From Etsy: BUY NOW: @physicsfun Rattleback

Wood Rattleback: spin reversing toy where a complicated combination of friction, precession, and instability induced vibrations transforms the rotational energy into into rattling (energy of oscillations) and then back into rotational energy in the opposite direction. The induced rattling is primarily due to the asymmetric shape of the bottom, like that of a propeller. Note the toy reverses almost immediately when spun clockwise, however, as demonstrated on the 3rd spin, this design will also reverse if spun counterclockwise! The reversal in this mode takes place after a while and only a 1/4 turn or so, but is predicted by theory yet rarely seen. @physicsfun exclusive! 

Micro Racer in a Glass

These micro racer cars are sold under many brand names, and most come with a clear sphere to demonstrate this centripetal acceleration phenomenon. 

From Amazon: BUY NOW: Micro Racer + Sphere

From eBay: BUY NOW: Micro Racer + Sphere

Micro Racer in a Glass: This tiny battery powered car overcomes gravity through centripetal acceleration and slight friction with the glass surface. With sufficient velocity the surface normal force supplies the centripetal acceleration. The car’s battery last for many minutes and is USB rechargeable.


Skew Dice (d6 and d12)

Get these skew dice here:

From Amazon: BUY NOW: Skew d6 set
From Amazon: BUY NOW: Skew d12 set

Click here for other amazing dice.

Skew Dice (d6 and d12): these dice are skewed- but their odds aren’t! These unusually shaped dice are completely fair- roll them and the probability of outcomes are identical to a standard set of dice. The odd shapes of the skew d6s are a special type of polyhedra called asymmetric trigonal trapezohedra, and these d12s are tetrahedic pentagon dodecahedrons (swipe). These skew forms come in right and left handed versions(swipe twice) and these sets come with one of each mirror image. What allows these shapes to be fair like a cube has to do with their property of being isohedral, where each face of an object will map onto all other faces via a symmetry of the object. Manufactured by The Dice Lab team of Robert Fathauer and Henry Segerman.

Sp!n Top

Get a Sp!n Top here:

From Art of Play: BUY NOW:  Sp!n Top

Sp!n Top: once set into motion the eye only perceives the punctuation mark ! in the center of a ring, with the vertical line seemingly suspended in space above the dot. The rate of spin is above the flicker fusion threshold of human vision, and the crossbars become blurred out and invisible- the effect is even more pronounced in person (hard to capture on video). Physics and psychophysics combine to produce this wonderful illusion!