DIY

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 

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. 

Impossible Braid 

Get this nice example of mystery braid here:

From Art of Play: BUY NOW: Impossible Braid Key Fob

Here is a great video on how to make the mystery braid

See other Impossible Objects in my collection. 

Mystery Braid: challenge- how can three strands be braided if both sets of ends are connected? (swipe for reveal) A new addition to my collection of “impossible objects”, this leather key fob is braided from a single piece of leather, constructed by making two parallel slits but not cutting the ends. The solution is well known to those in the field of leatherwork- due to a twist of topology it’s possible to make this braid if the number of left strand over right crossings equals the times the right strand crosses over the left. Four strands braided this way is not mathematically possible, but 3, 5, or any odd number can be done!

 

 

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. 


Glow Trace Chaotic Pendulum Kit

Get this super nice, affordable, and fun to assemble kit here:
From KiwiCo: BUY NOW: Glow Pendulum Kit

Get amazing quatilty science kits delievered to your home- this glow pendulum is part of the Tinker Crate subscription. 
From KiwiCo: LEARN MORE: Tinker Crate Subscription

Glow Trace Chaotic Pendulum: this fun and amazing DIY kit features a UV diode to trace the intricate path of this double pendulum system on to a phosphorescent screen, revealing the physics of chaotic motion. It’s amazing that such complex motion can arise from a simple assembly of two pendulums, one attached to the end of the other. Chaotic motion, such as that observed here, is characterized by extreme sensitivity to initial starting conditions, tiny differences in how the system is released leads to dramatically different outcomes each time. 

 

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. 

Salt Fractionation

All the ingredients are available from your local market/drugstore. The trick is to find a dye that works for acetone, but will not color water- believe it on not blue glitter will color the acetone nicely and not change the salt water. Follow this link for details: 
ChemEd X: Blog of Prof. Tom Kuntzleman 

Of course Amazon has what you will need:

From Amazon: BUY NOW 
acetoneblue glitterfood coloring, cool bottle 

Salt Fractionation: two liquids that won’t stay mixed! Acetone (dyed blue) floats on top of the higher density salt water (dyed orange). Acetone usually dissolves in water through hydrogen bonding interactions, but solubility can be altered. In a process called “salting out” a sufficient amount of salt is dissolved such that the water molecules, which are much more attracted to the resulting Na+ and Cl- ions (through ion-dipole bonds), will then ignore the weaker acetone hydrogen bonds. This results in the spontaneous separation (shown here in real time) of the liquids no matter how well shaken up. 


Tumble Rings

I made this set of tumble rings from reading Martin Gardner's description in his famous mathematical recreations books- highly recommended: 
From Amazon: BUY NOW Knots and Borromean Rings by Martin GardnerDescribes the Tumble Rings 

From Amazon: BUY NOW Books on recreational math and puzzles by Martin Gardner Lots of physics and math toys in these pages! 

Tumble Rings: the links in this chain are connected in a special way such that the top ring appears to tumble to the bottom- a compelling illusion! 

Faraday Train

Here's the parts to make your own: 
From eBay: BUY NOW Neodymium Spheres 15mm 
From Amazon: BUY NOW Bare Copper Wire 10 gauge 

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

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. 

Unmixing Density Column

The bottle used here is from Voss Water: a nice cylinder and the labels come off easily. Amazon has the ingedients:

From Amazon: BUY NOW 
acetoneblue glitterfood coloring, Voss Water

The density column I made for this video is based on blend of two ideas: this "science snack" from the exploratorium: Klutz-Proof Density Column and this ChemED X post: Blog of Prof. Tom Kuntzleman  

See my Salt Fractionation post for details. 

Unmixing Density Column: three liquids that won’t stay mixed! Acetone (dyed blue) floats on top of the higher density vegetable oil, which in turn floats atop salt water (dyed orange) which is more dense than oil. Acetone usually dissolves in water through hydrogen bonding interactions, but solubility can be altered. In a process called “salting out” a sufficient amount of salt is dissolved such that the water molecules, which are much more attracted to the resulting Na+ and Cl- ions (through ion-dipole bonds), will then ignore the weaker acetone hydrogen bonds. This results in the spontaneous separation of these three liquids no matter how well shaken up. 


Centripetal Spheres

Just thread a rubber band through two of these drilled steel balls and you are ready to go! 
From Amazon: BUY NOW 
Drilled Spheres 

Centripetal Spheres: two ball bearings connected by a rubber band orbit each other as energy oscillates between elastic potential energy and rotation kinetic energy. Just wind up the rubber band and let go. When the rubber band has unwound the rotational inertia of the bearings winds it back up until it changes direction. The process repeats until the initial energy is dissipated through friction.

Self Propelled Homopolar Motor

Here are disk magnets I used for the "wheels": 
From eBay: BUY NOW Neodymium Disk Magnets 
From eBay: BUY NOW Neodymium Disk Magnet 

Wire that looks and works well is just 10 gauge ground wire. Inexpensive and available at any local hardware store-- or order a small quantity here: 
From eBay: BUY NOW 10 gauge Copper Wire 

Wikipedia has some good details on the physics of homopolar motors 

Self Propelled Homopolar Motor: cylindrical neodymium magnets supply the static magnetic field for this motor and become the wheels of a very simple vehicle with an AA battery as the energy source. As soon as both ends of the copper wire make contact, an electric current will flow which in turn induces a magnetic field around the wire. This induced field around the copper wire will then interact with the neodymium magnets on each end causing them to spin- a wonderful example of a motor with minimal components.

Mobius Zipper

If you like this kind of math exploration I highly recommend this book by Matt Parker: 
From Amazon: BUY NOW 
Things to Make and Do in the Fourth Dimension 


... and any of the books by Martin Gardner 
 
From Amazon: BUY NOW 
Recreational Math Books 

The parts to make this are inexpensive- a great craft for kids. Sew on the velcro dots for best results:

From Amazon: BUY NOW: Nylon Zippers, Velcro Dots

Möbius Zipper: exploring topology with a bisecting strip (a zipper with velcro ends). 0 twists creates a cylinder which simply gives two cylinders when split, ½ twist creates a Möbius strip- splitting down the center produces one long loop with with two full twists, 1 twist in a loop-splitting in half produces two interlocked Möbius loops! Just some of the curious properties concerning the Möbius strip, an unorientable, one sided surface, with only one boundary. 


Magnetic Suspension Sculpture

The DIY version can be assemebled with these parts. Steel wire of guage 10 or 12 should work well. 

From Amazon: BUY NOW: Quilting Hoop, Neodyumium Magnet, Steel Wire

Magnetic Hoops Suspension Sculpture: Steel circles are suspended by a magnet (black sphere) and held down to the base by a thin thread. The tops of the steel hoops, being ferromagnetic, become a north pole in the presence of the south pole end of the black magnet, so they are attracted to the black magnet, but repel each other. Made by Rathcon Inc. in 1970. Swipe to see my DIY version made from a quilting hoop, neodymium magnets, and some bailing wire. 

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Floating Yen

These aluminium 1 Yen coins are the perfect denisty to float as shown in the video:

From Etsy: BUY NOW: 1-Yen Coins (20)

Floating Yen: the surface tension of water is strong enough to suspend the aluminum coin, and a trapped column of air in a second glass can submerge a portion of the surface with the coin. The 1-Yen coin has just the right mass and density for this demonstration. One of my favorite DIY physics demonstrations.


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

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!

Homopolar Motor

Fairly simple to make- here are the inexpensive supplies needed to make a few of these motors. 
AA batteries have a diameter of 14.5 mm, so a bottom magnet with a diameter of 15 mm is just right: 
From eBay: BUY NOW Neodymium Disk Magnet 

Wire that looks and works well is just 10 gauge ground wire. Inexpensive and available at any local hardware store-- or order a small quantity here: 
From eBay: BUY NOW 10 gauge Copper Wire 

Wikipedia has some good details on the physics of homopolar motors 

Homopolar Motor: a minimalist electric motor- battery, wire, and magnet. This type of motor does not need a commutator- the polarity of the electromagnetic coil does not need to reverse. The challenge with this design is balancing the coil to center on the battery as it rotates. A favorite DIY physics toy!

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

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!