Budget physics

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.

Magnetic Sand Hourglass

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From Educational Innovations: BUY NOW Magnetic Sand Timer 
From Amazon: BUY NOW Magnetic Hourglass 

Magnetic Sand Hourglass: ferromagnetic sand collects above a neodymium magnet in the wood base. Each particulate of ferromagnetic iron becomes a temporary dipole magnet in the presence of the magnetic field in the base. The tiny dipoles link up north ends to south ends, creating interesting patterns that reveal the magnetic field lines. 

Tensegrity for the Desk

Get this affordable physics tensegrity sculpture here:

From Etsy: BUY NOW: Tensegrity Sculpture

Tensegrity for the Desk: an elegant, and stackable, desk toy version of this popular tensegrity configuration by maker/designer Micah Murdoch. Constructed from poplar wood, the design assembles easily with clever ball and socket connectors at the ends of the nylon support lines (3 long, 1 short). Stacking them seems to only increase the illusion of floating with the subtle way these structures defy gravity. Another fun configuration of tensegrity concept, invented by Kenneth Snelson and made famous by the architect Buckminster Fuller in 1949.


Cartesian Diver

Glass divers available here: 
From Amazon: BUY NOW Glass Divers or this complete set Cartesian Diver Kit

Inexpensive and fun diver kits to make in a bottle available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 
 

Cartesian Divers: increasing pressure on the water compresses the air bubbles in the small glass vials filling them further with water making them sink. Pascal's principle states that any change in pressure on an enclosed fluid (such as pushing on the rubber cover) is transmitted evenly to every part of the fluid- the physics of hydraulic brakes! Named after the physicist and philosopher Rene Descartes.

Switch Pitch Ball

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From Edicational Innovations: BUY NOW: Switch Pitch Ball

Switch Pitch Ball: this spherical assembly changes color by turning inside out when tossed into the air. A favorite of my mechanical toys with surprising physics. Interestingly the advertisements for this toy incorrectly claim air drag is involved in the transformation. To understand why the ball inverts first note that the ball is made of multiple components hinged together. In launching the ball from the hand an upward acceleration results in a torque that pivots each component around its center of mass, causing the rotation of these components in an organized way leading to the transformation. Imagine tossing a stick straight up. If the stick is perfectly vertical upon launch it will move straight up- but if it is initially slanted at all it will also begin to rotate upon launch. Similar physics underlies the motion of each component of the ball- shown here in 240 fps slow motion. The Switch Pitch is produced by the makers of the Hoberman Sphere. 

Triple Pendulum Chaotic Fidget 

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From Amazon: BUY NOW: Triple Pendulum Spinner

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.


TrueBalance

Get the full version (8 disks made of wood) or the mini (6 disks, blue or red plastic): 
From Amazon: BUY NOW TrueBalance Coordination Puzzle 

TrueBalance: coordination challenge puzzle- get the six disks, connected by bearing swivels, into a vertical stack by only tilting the handle. Harder than it looks to get each disk’s center of mass above the one below at the same time into the unstable equilibrium final state. The swivels constrain the system, limiting the degrees of freedom, and allowing strange and interesting motion. Kinetic art as a toy! 

Happy/Sad Spheres

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From Educational Innovations: BUY NOW: Happy/Sad Balls

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.


Moiré Kinetic Wheel

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From Amazon: BUY NOW: Moiré Fidget Device

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.

Balance Pteranodon

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From Amazon: BUY NOW Balance Pteranodon 
From eBay: BUY NOW Balancing Pteranodon

Balance Pteranodon: 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. 


Sandscape Spontaneous Stratification 

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From Amazon: BUY NOW: Sandscape Kinetic Desk Toy

Click here for more amazing types of kinetic sand art. 

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. 

Precession of a Gyroscope

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From eBay: BUY NOW Gyroscopes 

Precession of a Gyroscope: in defiance of gravity this gyroscope is supported only at one end. The physics and vector nature of angular momentum! Note that as friction slows the rotor of the gyroscope down, the precession rotation rate gets faster and faster. After some energy loss the gyroscope contacts the table and vibrations move the unit around while the angular momentum maintains its orientation. 


Sphere Sticks Geometric Puzzle

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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. 

 

The Physics of Tippe-Top Inversion

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From Art of Play: BUY NOW Flip Over Tops

The Physics of Tippe-Top Inversion: spinning things often have surprising physics! From a talk I gave about this time last year at PhysicsCon 2020 held in Caltech’s Feynman Lecture Hall where I described the physics behind flip-over tops and other physics toys. In brief: friction with the surface provides a torque that acts on the existing angular momentum of the top to flip it over. The top will stay flipped until the spin rate slows down enough to where its center of mass pulls it back to the resting position. Inversion phase shown at 240fps- note the little hop the top takes as it goes on to its stem!

Static Spheres

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From Educational Innovations: BUY NOW: Static Spheres

Click here for other static electricity devices

Static Spheres: triboelectric effect toy. The red acetate spheres are given an acquired net negative charge, and their mutual repulsion allows them to jump a centimeter or more as charge is manipulated on the PET plastic container. Bringing an object near the container momentarily moves electrons (charge) around creating repulsive forces (sphere v. sphere) and attractive forces (spheres and container) resulting in the observed motions. The red spheres interact with each other without coming into physical contact (as shown in 240 fps slow motion) as like charges repel. Shaking the system a bit allows the red spheres to pick up charge in the first place by colliding with the container.