Volta’s Hailstorm and Electrophorus
This inexpensive electrophorus set works great!
From Amazon: BUY NOW Electrophorus Demonstration Set
The container is just the middle part cut from a plastic water bottle, and the "hail" stones are Styrofoam craft beads:
From Amazon: BUY NOW Styrofoam Craft Beads
For Volta's Hailstorm to work, the beads must be coated with a conducting spray (here is what I used):
From Amazon: BUY NOW Staticide Spray
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Wikipedia has a very nice description of the physics of the Electrophorus and how it is used to transfer electric charge.
Volta’s Hailstorm and Electrophorus: electrical forces due to electrostatic charge send foam beads flying in this version of the historic demonstration by physicist Alessandro Volta. The beads are covered with an electrically conductive coating allowing them to transfer charge from the environment to the plate of the electrophorus. The acrylic platform becomes negatively charged when rubbed with a paper napkin, but it is also an insulator so the charge on it can not flow on to the aluminum plate of the electrophorus. Instead the charge on the platform pushes electrons to the top of the plate (like signs repel) and touching the plate results in a spark that removes the electrons giving the plate a significant positive charge that will then attract the beads.
Bottle, Hoop, and Nail Trick
The hoop used is just the inner circle of an embroidery hoop. Get one for a couple dollars here:
From Amazon: BUY NOW Wooden Hoop
The science writer Martin Gardner has published many books of physics tricks and simple but amazing science experiments like the one in this video. Highly recommended.
From Amazon: BUY NOW Martin Gardner's Science Magic: Tricks and Puzzles
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Bottle, Hoop, and Nail Trick: with some practice, a snap of the wrist removes the hoop and the nail falls straight into the bottle. Newton's 1st Law as seen in slow motion- a mass at rest tends to stay at rest. (Best to watch with sound/audio) Balancing the nail on the hoop ensures the nail is directly over the top of the bottle. The hoop is removed so quickly that it does not interact significantly with the sufficiently massive nail, and thus the nail remains over the mouth of the bottle so that gravity pulls it in. G4G Week repost- a favorite from Martin Gardner’s collections of physics tricks.
Faraday Train
The wire used for the Faraday Train has to be bare- so make sure it does not have any kind of clear coating on it. The solid grounding wire sold at hardware stores works great.
Here is a nice description of the Faraday Train and the physics of its propulsion.
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Faraday Train: two magnets, one battery, and a coil of bare copper wire are the simple essence of this self propelled craft. The magnets conduct electricity, thus when put in contact with the coil current will flow creating a solenoidal magnetic field in the vicinity of the battery, which in turn pushes on the magnets at each end of the battery moving the craft along. The spherical neodymium magnets used allows the craft to slide along the coil with minimal friction.
Super Absorbent Polymer
Get some of these grow-spheres here:
From Educational Innovations: BUY NOW Growing Spheres
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Super Absorbent Polymer: poly-acrylamide polymer crystals are able to absorb up to 200 times their volume of water. Here seven small spheres, approximately 4mm in diameter, were immersed in water for three hours, after which they were slightly more than 23mm across. The final gel sphere is more than 99.5% water- and they bounce!
Micro Hoverboard
Micro-Hoverboard: diamagnetic levitation technology- although Marty McFly would have to be three inches tall to ride this hoverboard. Made from printed paper and pyrolytic graphite with concentric circular neodymium magnet array. The magnetic rings alternate between north and south magnetic poles in just the right way to trap this special type of graphite. Pyrolytic graphite has strong diamagnetic properties such that it develops an opposite (but weak)magnetic field when in the presence of a magnetic field from another source. Swipe to see the graphite pieces levitating individually.
Polarizing Filter Black Wall Illusion
Amazon lists acrylic tubing at a reasonable price: get a 2 foot long tube with an inner diameter of 1.5 inches for about $17 US. This will accommodate a large marble for the demonstration.
From Amazon: BUY NOW Acrylic Tubing
For a 1.5 inch inner diameter (3.8 cm) tube you will need a 10 inch (25.4 cm) wide sheet to complete a cylinder inside the tube.
From Educational Innovations: BUY NOW Polarizing Film
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Polarizing Filter Black Wall Illusion: two sheets of polarizing film (with polarization axes oriented at 90 degrees to each other) create this illusion inside an acrylic tube. Physics magic!
Self-Propelled Homopolar Motor on Aluminum Foil Racetrack
I used neodymium disk magnets, small end = 1/2" diameter, Large end = 3/4" diameter.
From Amazon: BUY NOW Disk Magnets for Simple Motor
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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.
Sucrose Crystals
Edible and pretty sugar crystal clusters available here:
From Etsy: BUY NOW: Sucrose Crystal Clusters on a Stick
and here is a fun page describing how to grow large clear sugar crystals at home.
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Sucrose Crystals: so I recently found, in the back corner of my kitchen panty, this bottle of fancy maple syrup I bought a long time ago. Apparently the conditions in my pantry were just right to allow the sugar to form these large prismatic clear crystals. Sucrose is a complex molecule (C12H22O11) but forms crystals of elongated polyhedra often with irregular hexagonal forms as seen here. I soaked the label off this bottle to better view the crystals- and I put it back in the cupboard it to see if the crystals will grow further- accidental kitchen physics experiment in progress!
Pickagram Puzzle
Get this well made puzzle here:
From Art of Play: BUY NOW: PIckagram Puzzle
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Pickagram: an innovative update on the classic Tangram puzzle- magnets added! With pieces that cling together with a satisfying snap, the 2D puzzle formations become 3D abstract sculptures that can stand on their own. From the mind of designer and architect Gilryong Song, with inspiration from the golden ratio in its proportions and angles.
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
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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.
Ferromagnetic Interaction
Here is the NdFeB neodymium magnet used in this video:
From Amazon: BUY NOW: Neodymium Disk Magnet
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Please use extreme caution when handeling strong magnets like this one. Small nails, paperclips, staples and other houlshold object made with iron will interact interestingly with the magnetic field.
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.
Natural Mineral Fluorescence
Get ruby in matrix stones and jewelry here:
From Etsy: BUY NOW: Ruby Glow Stones
and find the sodalite bright orange fluorescent syenite here:
From Etsy: BUY NOW: Orange Glow Stones
You will also want an awesome UV flashlight like this one:
From Amazon: BUY NOW: High Power UV Light
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Natural Mineral Fluorescence: Four mineral specimens that emit a surprising bright glow under long wave ultraviolet light (from left to right): a clear calcite crystal glows pink, a carved obelisk of grey syenite with grains of sodalite(bright orange), a carved piece of green fuchsite with red ruby inclusions(red glow) and veins of white calcite(bright white), and a polished slab of lapis lazuli with speckles of the mineral hauynite (yellow glow). The colorful glow comes from complex quantum mechanical behavior where high energy UV photons are absorbed and then lower energy photons are emitted- the physics of fluorescence.
"Impossible" Domino
Get the 3D print files here:
From Cults3D.com: Download Now: Impossible Domino
This video from The Action Lab has a good decription of rhe physics.
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“Impossible” Domino: a pair of specially engineered domino type objects where the right domino knocks over the left one, but then stands back up! When seen in slow motion the process becomes more clear. The main factor here is that the center of mass of the left domino is higher than that of the right one, giving it much more potential energy so when the left one topples over it can transfer some energy back to the right one. Created by the folks at viralvideolab and 3D printed by my friend Roger Key (thanks!)
In Defiance of Gravity
Neodymium magnets will produce the largest gap when suspending a nail or other iron rich objects.
Please use exterme caution when handling these magnets.
From Amazon: BUY NOW: Neodymium Super Magnet
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In Defiance of Gravity: a 3 oz plumb bob in suspension 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. Sculpture: oak, stainless steel chain and hardware, neodymium super magnet, standard plumb bob tool. Iron filings in oil align and chain together to reveal the magnetic field lines of the equilibrium configuration.
Wringing Guage Blocks
Guage block sets can be a bit pricy, but some fairly inexpensive pieces and small sets can be found for demonstrations and such:
From Amazon: BUY NOW: Gauge Blocks
Wikipedia has a nice description of Gauge Blocks and the Phenomenon of Wringing
Note: this site contains affiliate links for which I may be compensated
Wringing Gauge Blocks: two blocks of metal (not magnets!) will stick together by a process called wringing if their surfaces are flat to high precision- such as these gauge blocks found in most machine shops. Here two blocks are forced apart with a snap, and then wrung back together with the characteristic sliding motion technique. Gauge blocks are flat to less that one millionth of a meter and are used by machinists for precision length measurements and calibration. The science of the wring force remains somewhat a mystery and no one has yet found a fully excepted physics description- but we do know that blocks will wring in a vacuum and that the force can be up to 30 times that of weight of the blocks. Fun physics from the shop!
Gosper Fractal Fidget
The 3D Print files are available here:
From Printables: Download Now: Gosper Fractal Fidget
Gosper Fractal Fidget: exploring geometry and elasticity. For any given shape of elastic ribbon what would it look like if flipped inside-out? Surprising results often follow. I received this amazing item in the G4G gift exchange at the Gathering for Gardner conference back in February. Designed and printed by Thomas Draper
Vortex Pyramid Fidget
Get this kinetic object here:
From ETSY: BUY NOW: Vortex Pyramid Passthrough Fidget
or use these files to print it uourself:
From Printables: Download Now: Pyramid Passthrough Fidget
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Vortex Pyramid Fidget: a four sided pyramid is dissected by a spiral cut in the shape of an eight petal flower (as seen from the bottom) in this math inspired kinetic toy. The interesting behavior stems from the connection between translational motion and rotational motion and the precision manufacturing allowed by the 3D printing process. An amazing creation by RJ Design and expertly printed by my friend Jason Veatch.