DIY

Fluorescein v. Laser Frequency

Need a laser pointer? Incredibly, you can get 3 (one of each color) for under $20 (including S&H): 
From Amazon: BUY NOW Red+Green+Purple Laser Pointer

Make you own fluorescent solution with this powder: 
From Etsy/STEMCell Science: BUY NOW: Fluorescein Powder

Fluorescein v. Laser Frequency: exploring how this famous fluorescent dye reacts to three frequencies of laser pointer using this unique liquid filled paperweight. Under Green (532 nm) we see some mild yellow fluorescence as the beam transmits through the liquid, under Red (635 nm) the beam transmits with no reaction, but under near UV Blue (450 nm) the beam is completely absorbed near the liquid surface and re-emitted in bright green with a peak at 515nm. A fun home experiment to explore quantum physics phenomena with inexpensive apparatus.

Electromagnetic Levitation Module

Get this kit here (comes complete as shown in my video):
From engineDIY: BUY NOW: Magnetic Levitation Module

The featured sculture is by Bathsheba Grossman, affordable and beautiful math art available here:
From Etsy: BUY NOW: Soliton Sculpture

Electromagnetic Levitation Module: this engineered control system uses adjustable electromagnets (four copper coils) and and two Hall effect magnetic field sensors (held firm embedded in white silicone) to levitate an 5cm diameter neodymium magnet platform about 3 cm in mid-air. A feedback loop informed by the Hall effect sensors allows fine tuning of the magnetic field to exactly balance the pull of gravity, and is powered by a standard USB connection. The platform also rotates, perfect for showcasing one of my metal 3D printed mathematical sculptures by Bathsheba Grossman.

Magentic Dandelion 

Here is a very powerful NdFeB neodymium magnet that will work withlarger nails: 

From Amazon: BUY NOW: Neodymium Disk Magnet

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. 

Magnetic Dandelion: through ferromagnetic interaction these iron rich nails temporarily become dipole magnets in the presence of an intense magnetic field from a 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 becomes 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. 


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!

 

 

Ferromagnetic Interaction

Here is the NdFeB neodymium magnet used in this video:

From Amazon: BUY NOW: Neodymium Disk Magnet

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.

Electric Motor

Get this easy to assemble kit here: 
From Educational Innovations: BUY NOW Simplest Motor Kit 

Electric Motor: in its simplest form!- coil, magnet, and battery. The wire of the coil has an insulating coating- and this coating is carefully scrapped off one side on each end. When current passes through the coil it becomes an electromagnet and the permanent magnet repels it making it spin- as it turns the currents goes on and off depending if the copper posts are in contact with the bare wire (current on) or the still insulated wire (current off). I have motors with fewer parts- but they operate on more complex principles.


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.

Volta’s Hailstorm and Electrophorus

This inexpensive electrophorus set works great! 
From Amazon: BUY NOW Electrophorus Demonstration Set 
From eBay: 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 

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. 

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 

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.


Glow Trace Chaotic Pendulum Kit

This kit (usually part of a subscription) often available here:
From eBay: 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. 

 

PDLC Electric Field Induced Transparancy

Get this device here:

From Amazon: BUY NOW: PDLC Smartwindow Sample

and click here for the balancing dragon toy

PDLC Electric Field Induced Transparency: when a voltage is placed across Polymer-Dispersed Liquid-Crystal film, long skinny molecules align with the electric field allowing light to pass through without scattering- with the field off the molecules thermally randomize and then do scatter the light passing through, producing a milky white translucent appearance. This sample of a “smart window” is powered by a 1.5 Volt AA battery and has very thin metallic coating on the front and back. A fun demonstration of electrochromic materials.