All physicsfun toys

Reverse Cartesian Diver

Glass divers available here: 
From Amazon: BUY NOW Glass Divers 

The reverse diver needs a bottle with a oval shaped cross section. I used the bottle from this product- it has the right shape and size and the label comes off easily: 
 
From Amazon: BUY NOW Oval Shaped Bottle Source 

Inexpensive and fun diver kits available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 

Wikipedia has the details on the Cartesian diver (and reverse diver)

Reverse Cartesian Diver: physics puzzle (swipe for hint). On the left is a Cartesian diver- pressing on the bottle forces water into the glass diver, which then compresses the bubble in diver’s head allowing it to sink. On the right is a reverse Cartesian diver- again the bottle is pinched but this time the diver ascends- why? 

The iTOP

Well engineered brass spinning toys by SiriusEnigmas:

From Etsy: BUY NOW: The iTOP 

From Etsy: BUY NOW: The PhiTOP

From Etsy: BUY NOW: The eTOP

From Etsy: BUY NOW: The PiTOP

The iTOP: inverting spinning disk- the equilibrium state for a spinning thing is often different from that of the same object when stationary. When spun, the iTOP almost instantly inverts to raise its center of mass (shown in slow motion because it happens so fast). However, when the rotation speed decreases to a certain rate the system becomes unstable (shown again in slow motion) and flips again before going into a rolling/spinning motion like a coin. This top completes the set of four spin tops by astrophysicist Kenneth Brecher, all made of polished brass and themed on a mathematical constant. Swipe to see a demonstration of each: iTOP (square-root of -1), PhiTOP (golden ratio, φ), eTOP (base of the natural log), and the PiTOP (C/D of a circle, π). 

 


Magnetron Chaotic Rotors

Sometimes available on eBay: 
From eBay: Search NOW Magnetron Chaotic Rotator 

Click this link for another toy featuring the math of chaos theory! 

Chaotic Coupled Rotors: kinetic energy is passed back and forth chaotically due to magnets mounted on the the ends of the spines that repel. This toy was marketed under the name Magnetron and sold in the Natural Wonders shops in the 1990s-sometimes available on eBay.

The PiTOP

Well engineered brass spinning toys by SiriusEnigmas

From Etsy: BUY NOW: The PiTOP

From Etsy: BUY NOW: The PhiTOP 

The PiTOP: this beautiful brass cylinder has a radius of 1 inch, a height of 1/π inches, and displays the first 109 digits of π on its face. Spin this disk (best with sound on) and it will demonstrate some very interesting physics involving energy transfer and conservation of angular momentum. The edges of the cylinder are rounded and engineered to exhibit an optimum motion of a “spolling” coin, a motion that combines spinning and rolling (closeup shown in 240fps). As the disk’s angle of inclination decreases the speed of the rolling increases dramatically until the contact point with the mirror is moving in excess of 200mph. From the mind of physicist Ken Brecher, inventor of the PhiTOP (swipe for video). Note also that with the specified height, that the volume of this cylinder is exactly 1 cubic inch! 

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. 


Diamagnetic Racetrack

Simiar diamagnetic levitation kits are available here: 
From eBay: BUY NOW Diamagnetic Levitation Kit

Diamagnetic Racetrack: thin pyrolytic graphite sheets levitate above powerful magnets. A set of five concentric neodymium magnets, alternating N-S-N-S-N comprise the racetrack and form the trapping field. Diamagnetic substances develop temporary repulsive magnetic fields only when they are in the presence of a magnetic field from some other source. Graphite of this sort is the most diamagnetic substance known.

Magnetic Influence on Aluminum

For this demonstration stronger magnets work best:
From Amazon: BUY NOW: Neodymium Magnets

Here is a good small turntable with bearings: 
From Amazon: BUY NOW: Spinning Base

Magnetic Influence on Aluminum: physics puzzler- spin a magnet under a beer can suspended by a thread, and the can will turn. Why? Aluminum is not ferromagnetic, and as shown, magnets are not attracted to the can.  So how does a spinning magnet influence the can to spin? 

 

 

 

Answer: the can spins due to eddy currents induced in the conducting aluminum due to the moving magnetic fields underneath. The eddy currents make the can into a temporary electromagnet that then interacts with the magnets below according to the famous law by Lenz.

Sodalite Fluorescence 

Get sodalite-bearing syenite river stones here:

From Etsy: BUY NOW: Sodalite Glow Rocks

You will also want an awesome UV flashlight like this one:

From Amazon: BUY NOW: High Power UV Light

Sodalite Fluorescence: in daylight this rock looks like an ordinary river stone, but when illuminated with long wave ultraviolet light, patches of the mineral sodalite shine in bright orange glow. These stones are comprised of sodalite-bearing syenite, where syenite is a course grained igneous rock similar to granite but deficient in quartz. Found on the shores of Lake Superior- discovered in 2017 by Erik Rintamaki.

 


Corona Discharge Trajectories

Mini Tesla coil with wire end attachment- get one here: 
From engineDIY: BUY NOW: Mini Tesla Coil

Long exposure image captured using this Slow Shutter app: 
 
From App Store: BUY NOW: Slow Shutter Cam 

Corona Discharge Trajectories: the ejected electron stream propels the end of a thin wire connected to a miniature Tesla coil. The corona discharge creates a glowing plasma at the end of the wire, but also imparts momenta that pushes the wire’s end into a final state circular orbit. The more interesting behavior occurs during the initial transient orbits which seem to be hypotrochoid type curves beautifully captured here using the Slow Shutter app. Please see seven posts back for details about this mini Tesla coil. 

Moiré Kinetic Wheel

Get this device (and other variations) here:

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.

Impossible Nail

Nice versions are curretnly available from Etsy:

From Etsy: BUY NOW: Impossible Nail

Impossible Nail: An eighteen-penny nail driven through the inner notches of a solid piece of wood. The wood was notched and the nail added- no glue used or cuts made, and the nail is solid and in one piece. Not impossible, but creating this does depend on the use of some amazing physical properties of wood. I won’t reveal the method here but a quick search on YouTube produces a few how-to videos showing the process. 


Bismuth Diamagnetic Levitation

Get these 99.9% pure element Bi 83 cubes here:
From Luciteria: BUY NOW: Bismuth Element Cube

Many combinations of strong neodymium magnets will work, here are the versions I used:
From Amazon: BUY NOW: Cylindrical Neodymium Magnet
From eBay: BUY NOW: Tiny Neodymium Cube Magnets

See my video of other pure element cubes by Luciteria Science

Bismuth Diamagnetic Levitation: Element 83 (bismuth) is the most diamagnetic of the elements*. Here a small neodymium magnet is made to float between two 99% pure bismuth 10mm cubes which are held in precise configuration by friction with the parallel walls of the acrylic assembly I made. Diamagnetic substances only have magnetic fields of their own when placed in an external magnetic field from another source- here the tiny cube magnet supplies the field. Diamagnetic fields are pretty weak though so a powerful cylindrical neodymium magnet sits above the cubes and is adjusted to help lift the tiny cube magnet against gravity. *except for a special form of carbon known as pyrolytic graphite.

High Voltage Wood Burn Fractal

Beautiful wood fractal art available here:

From Etsy: BUY NOW: High Voltage Fractal Art

High Voltage Wood Burn Fractal: a classic Lichtenberg fractal created by electrical discharge- in this piece artist/maker Nic Ferretti applied cobalt blue epoxy resin to fill the cavities of the burn pattern and create the look of frozen lightning. Swipe to see my attempt at this process with an old neon sign high voltage transformer using 7500 V at 20 mA. I turned the power off right before the two sides connected to get the fern-like look. The wood is slightly wetted with baking soda dissolved in tap water. WARNING high voltage can kill- do not use a transformer like this unless you are fully trained in electrical high voltage safety. 

Slinky Treadmill

Learn more about the physics of the slinky here: Exploratorium Science Snack 
The slinky has been a popular toy since 1945! Read about the history and physics of the slinky, and the naval mechanical engineer that invented it on Wikipedia
Visit the Exploratorium 

Slinky Treadmill by @exploratorium: kinetic motion energy transfers to elastic potential energy and then back to kinetic energy in a cycling process as a slinky spring "walks" down an incline. Put the system on a treadmill, such as this one at the Exploratorium in San Francisco, and the walking behavior can be explored for many minutes. Note that after a while the slinky's walking becomes erratic.? With special thanks to the Exploratorium!


Ice Melt Demo

Get this similar demonstration kit here:
From Educational Innovations: BUY NOW
Ice Blocks Melt Demo

Ice Melt Demonstration: Wood or Aluminum- which will melt the ice fastest and why? Both blocks start at the same temperature (room temp) and have the same shape and volume. Swipe to reveal result shown in real time (not sped up!) Hint: Although both blocks are at the same temperature, the aluminum feels cool to the touch and the wood block feels warm. Those who have taken basic physics should have an advantage on this question- one block is an excellent insulator and the other a conductor.

The Milky Way in a Sphere

Created by Clemens & Christoph of CinkS labs: Available in a cube too! 
From CinkS Labs: BUY NOW: Milky Way in a Sphere

Special offer for physicsfun folowers: Use code POCKETUS and get a free Pocket Universe with your order of a sphere. Just add the Pocket Universe to your cart and apply the code. 

Click here for Universe Sphere

The Milky Way in a Sphere: the distribution of stars in our home galaxy, laser etched into a crystal sphere, according to the most recent telescopic surveys and mappings- including the stars in the Sagittarius Dwarf Galaxy (a small galaxy that is simultaneously orbiting and getting absorbed into the Milky Way) and the major globular clusters outside the main disk. Another beautiful object created by CinkS Labs.

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

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.