Budget physics

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

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". 

Rheoscopic Sworld

Get a Sworld ball (choose a color) here:

From Amazon: BUY NOW: Sworld Rheoscopic Ball

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. 


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. 


Polarization Test Card

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. 

 

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! 


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.

 

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! 

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.


Ring Catch Chain Trick

Get a set here: 
From eBay:(best selecton) BUY NOW Ring Chain Catch
From Amazon: BUY NOW Ring and Chain Set 

The physics of this trick in great detail with more slow motion: Ring Falling into a Chain: No Magic — Just Physics 

Ring Catch Chain Trick: a solid ring will be caught by a loop of chain if it tumbles during its fall. By Newton's Third law, when the ring twists into and hits the chain, the impact transfers momentum to the end of the chain, which rises up and over the ring- seen here in 480 fps slow motion. 

Memory Spring

Available here: 
From Mindsets: BUY NOW 
Memory Springs 

Affordable samples and kits here:
From Educational Innovations: BUY NOW: Energy Wire 

Similar produces featuring Nitinol Memory Wire: 
From Amazon: BUY NOW 
Nitinol Memory Wire Kits 

Memory Spring: some special alloys of brass can be made to have a shape memory triggered by temperature. These springs quickly change their length from 1 cm to 2.5cm when heated above 90 C (done here with hot water) and just as quickly shrink back to original size when cooled (immersed in cold water). Useful in many applications, especially things like automatic fire sprinkler valves and thermostats in car engines. This amazing property is related to a solid state phase transition similar to that of Nitinol wire called a Martensitic transformation.

Top Secret

This physics toy top is available here: 

From Amazon: BUY NOW Mystery Spinning Top

From eBay: BUY NOW Mystery Spinning Top 


The amazing green magnetic viewing film is also available: 
From Educational Innovations: BUY NOW Magnetic Field Viewing Film 

Here is the 1974 patent showing the very simple circuit of this device. The spinning dipole (the top itself) induces a current in one of the coils, and this current is fed to the base of the transistor turning the electromagnet on when the top is near. 
 

"Top Secret": this top will stay spinning for more than a week- because it is actually a motor! The top is a dipole magnet (as revealed by Magneview film) and the base has an electromagnet that gives the dipole a push when the top comes near the center. An ingeniously simple circuit consisting of only a battery, a coil, and a transistor, is activated when the spinning magnet nears the coil turning on the electromagnet to give a boost to the spin of the magnetic top.