Magnetic Toys

Iron Filings in Silicone Oil Suspension

Available from these fine sources: 

From Amazon: BUY NOW Magnetic Field Viewer Set (get the demo set)

Similar device here:
From Educational Innovations: BUY NOW Magnetic Field Viewer with Magnet 

Iron Filings in Silicone Oil Suspension ( Iron filing field detector ): visualizing the invisible- the magnetic field lines around a horseshoe magnet. In the presence of a magnetic field, ferromagnetic materials (such as iron) temporarily become magnets. Here the iron filings become dipole magnets and link up and align like tiny compass needles to follow and reveal the magnetic field lines associated with the permanent magnet underneath. Viscous silicone oil temporarily keeps the iron particles suspended yet allows for rotation and repositioning under the influence of the magnetic field.

 

Magneview Flim

Get some magnetic viewing film here: 
From Educational Innovations: BUY NOW Magnetic Viewing Film 

Magneview Flim: making the invisible visible and revealing the hidden physics of our everyday world. Microscopic cavities in this green film are filled with oil and tiny flakes of Nickel metal- like compass needles, the flakes align with the magnetic fields revealing the complexity of the north and south pole domains of these magnets. Two of the disk magnets have multiple north and south poles and look like gears with teeth- these are rotors from small motors. 

Vertical Mendocino Motor

Get this device for a great price here:

From EngineDIY: BUY NOW: Vertical Mendocino Motor

Vertical Mendocino Motor: each face of solar cell is connected to a coil of copper wire. Spins fast and quite in a sunny window. As the rotor turns each solar cell takes a turn in the brightest light, which provides electric current to one of the coils which becomes a temporary electromagnet that pushes against the permanent magnet configuration in the center- propelling the rotor to rotate. The rotor assembly is nicely symmetric and balances on a sharp point for minimal friction. Invented in the 1960s by Daryl Chapin of Bell Labs and popularized by Larry Springs of Mendocino CA 


The Levitron

Levitron Tops were produced in the 1990s and are out of production and getting harder to find. Some models are still available here: 
From eBay: BUY NOW 
Levitron Top 

The Levitron: spin stabilized magnetic levitation- will fly for about 3 minutes or more per launch. The spin rate of the magnetic top must be just right for flight, not too fast or too slow. Air resistance and dissipative interactions between the magnets gradually slow the spin rate and the top falls. Interestingly trapping the top requires precision - the weight of the top must be adjusted to within 1 gram to achieve equilibrium between the pull of gravity and the magnetic repulsion from the large donut shaped magnet in the wood base. Repost of my favorite physics toy in my collection.

spYke Ferrofluid Display Cell

Check out the Etsy page of CZFerro: imaginative and quality ferrofluid display cells 
On Etsy: BUY NOW Magnetic Fluid Sculptures 

spYke Ferrofluid Display Cell: another spectacular display cell by czferro featuring a colloidal ferromagnetic liquid in a specially prepared water-alcohol suspension. The orange background highlights the curious spiking behavior of the black ferrofluid- a result of the interplay between magnetic force and surface tension between the liquids. 

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.


Gravity Defying Nail and Magnet

Neodymium magnets will produce the largest gap when suspending a nail.
Please use exterme caution when handling these magnets. 

From Amazon: BUY NOW: Neodymium Super Magnet

Magnetic Defiance of Gravity: a nail suspended between a chain and a powerful neodymium magnet. Ferromagnetic attraction over a distance of many millimeters, and a reminder of the presence of the typically invisible electromagnetic forces all around us. Make your own with a paperclip, string, and a refrigerator magnet- or get a neodymium magnet and see how massive an object you can suspend in air. 

Chaotic magnetic Pendulum

These chaotic pendula are still available on eBay!

From eBay: BUY NOW: Krazy Leg Pendulum

Chaotic Magnet Pendulum: adding magnetic forces to gravity gives this pendulum chaotic motion- not random, but very sensitive to slight differences in initial launch conditions. Swipe to see a particular launch path that begins with a semi-stable orbit but then goes chaotic, captured with an attached LED and recorded with a slow shutter app. Arranging the dipoles magnets on the base leads to different patterns of motion- here white attracts and black repels. This vintage device is from the 1970s and was sold by the name “Krazy Leg” by Rathcon Inc.

Ferromagnetic Interaction

Here is the NdFeB neodymium magnet used in this video:

From Amazon: BUY NOW: Neodymium Disk Magnet

Please use cuation when handeling strong magnets like this one. Small nails, paperclips, staples and other houlshold object made with iron will interact interestingly with the magnetic feild. 

Ferromagnetic Interaction: iron rich nails temporarily become dipole magnets in the presence of an intense magnetic field from a large neodymium super magnet. Here the neodymium disk magnet is set with its north pole pointing up, so the point of each nail becomes a south pole (repelling each other) and the head of each a north pole. Imbued with these temporary induced fields, the nails will try to align themselves with the neodymium dipole’s field like compass needles, and the nails will interact with each other in interesting ways.


Revolution

This vintage toy can sometimes be found on eBay. 
Quality models of the modern version of this physics toy are still available 
From Educational Innovations: BUY NOW Magnetic Levitator 
From Amazon: BUY NOW Magnetic Levitator 

Revolution: vintage 2D magnetic levitation- permanent magnets can only produce static equilibrium along two dimensions- here a glass mirror constrains the third dimension, and makes for a nice bearing surface for rotation. This item was sold in the 1990s in mall shops such as Natural Wonders. 

Paperclip Magnetic Top

These tops will work with a paperclip too: 
From Amazon: BUY NOW Magnetic Tipped Top 
From eBay: BUY NOW  Magnetic Tipped Top

Paperclip Magnetic Top: the magnetic tipped top attaches to the perimeter of the paperclip- but since the top has much more mass, the paperclip is put into curious motion due to Newton's 3rd law and the top's rotational inertia. This transparent version allows full view of the moving clip. Patented in 1946 under the name Hoy-Poy Top, this antique kinetic art toy made it into my collection as a gift from the folks at @shirepostmint- thanks! 

Magnetic Newton's Cradle

This magnetic version fo Newton's cradle is no lomnger in production, but somtimes found on ebay:
From eBay: Search NOW: Magnetic Newon's Cradle

Here are some nice versions of the classic Newton's Cradle 
and here is a nice Magnetic Replusion Demonstration

Magnetic Newton's Cradle: the famous collision demonstration reimagined with opposing magnets as the pendulum weights- shown here in two modes of operation. Initially the collision pattern looks similar to the traditional colliding spheres version but quickly goes chaotic- the magnetic field of each weight interacts with all the other magnets simultaneously making the system nonlinear. A 1990s desk toy by Fascinations- sadly no longer in production. 


Toy Car with Magnetic Suspension Wheels

Available from these shops in Germany: 
From experimentis-shop.de: BUY NOW 
Mabrino Car 

From mabro.com: BUY NOW 
Mabrino Car 


Similar toys available here: 
From eBay: BUY NOW 
Tegu Cars 

From Amazon: BUY NOW 
Tegu Car Sets

Toy Car with Magnetic Suspension Wheels: Simple block car with clever wheel design. Small neodymium magnets embedded in the block lock on to steel balls, which raise the vehicle and become free to rotate providing the wheels for this simple toy.

The Levimoon

Get a levitating moon globe lamp here! 
FromAmazon: BUY NOW Levitating Moon Globe Lamp

The Levimoon: this detailed moon globe is an adjustable lamp that levitates! Charged through wireless induction via the base, the moon floats above the Earth while illuminated from the inside to reveal the major features of the lunar surface, and will rotate when given a slight push. This kind of levitation uses a control system with an adjustable electromagnet in a feedback loop with Hall effect sensors which allows for fine tuning of the magnetic field to exactly balance the pull of gravity. 


Ferrofluid Interactive Lava Lamp

Available here:
From Amazon: BUY NOW Ferrofluid Lava Lamp

Ferrofluid Interactive Lava Lamp: special ferrofluid infused wax allows manipulation of the blobs of “lava” with a weak magnet, adding an interactive element to the already mesmerizing physics of convective heat flow, Archimedes principle, and immiscible liquids. Love the atomic rocket theme on this updated version of the 1960s classic physics toy. 

Electric Motor/Generator

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.

Lenz's Law

Get a similar kit here: 
From Educational Innovations: BUY NOW Eddy Current tubes

Get some magnetic viewing film here: 
From Educational Innovations: BUY NOW Magnetic Viewing Film 

Lenz's Law: a strong neodymium magnet falls slowly down a copper bus bar as though passing through a viscous liquid. Since magnetic fields pass through copper, magneview film reveals the location of the falling dipole magnet. Moving magnetic fields from the falling magnet produce electric currents in the copper. These currents then produce magnetic fields that have the opposite polarity to the initial field. So a falling magnet makes the copper pipe briefly into an electromagnet that repels the magnet. The rectangular copper “pipe” is from a water-cooled electromagnet power supply line, 1.5 x 2 in (4 x 5 cm) in cross-section, designed to supply a steady DC current of 5000 amps. This 15” long piece weighs in at 12 lbs and has a 1/2” diameter hole for coolIng water to flow down its center. From a decommissioned particle accelerator magnet.