Budget physics

Simple Stirling Engine

Get this amazing model engine here:

From EngineDIY: BUY NOW: Simple Stilring Engine

See other featured DYI devices here: EngineDIY Models

Simple Stirling Engine: Perhaps the simplest piston engine ever devised- a single piston powered by a tiny alcohol lamp. Glass components allow a view of the internal workings of this design, and the interesting startup behavior from oscillation to full rotation. Heat engines produce mechanical motion from a difference in temperature- here the piston side is near room temperature (the central aluminum post is an excellent conductor and acts as a heat sink as the gas flows through), and the test tube is kept at high temperature via the flame, with metal fibers to help conduct the heat into the air (this component is called the regenerator). Swipe to see the elegant assembly of this model, and swipe again to see the engine power down. This external combustion design is attributed to Scottish engineer Robert Stirling back in 1816.

Light Pipe Sculpture

Get an affordable pre-bent light pipe demo here:
From Amazon: BUY NOW: Light Pipe Demo

Blue laser pointers (445nm) available here:
From eBay: BUY NOW: Blue Laser
but any color laser will work. 

Make your own abstract light pipe sculpture, an inexpesive heat gun is the only needed tool:
Materials from eBay: BUY NOW: Acrylic Rod
Tool from Amazon: BUY NOW: Heat Gun

Light Pipe Sculpture: internal reflection constrains most of the laser light to propagate along the bent acrylic rod- the physics of fiber optics. This abstract sculpture was created by applying a heat gun to a 3/8” diameter acrylic rod. The laser pointer used here is blue at a wavelength of 445nm.

Vortex by Lava Lamp

A DIY kit by the makers of Lava Lamp, home experimentation set with booklet of ideas to try:

From Amazon: BUY NOW: Lava Lamp LED Vortex kit

From eBay: BUY NOW: Lava Lamp LED Vortex kit

Vortex Lamp: a simple whirlpool powered by a magnetic stirrer like those in a chemistry lab and lit by LEDs. A DIY kit by Lava Lamp brand- which comes with glitter and beads, but I found the water vortex alone was mesmerizing to watch. Note the intricately changing structure of the vortex in the slow motion close up. 


Centripetal Kinetic Toy

This "iBall" desk toy is no longer in producltion. Howerver, a similar version of this toy can be made from these components:

From Amazon: BUY NOW: two piece acrylic shell

From Amazon: BUY NOW: 1/4 inch ball bearings

Centripetal Kinetic Toy: seven rolling steel balls hug to the inside of the acrylic sphere given sufficient velocity. Here the balls are launched such that their orbits are in the same plane, and due to their angular momentum (and a torque due to gravity) the plane of rotation precesses like the axis of a spinning top until friction slows them down. This toy was made in 2007 (sadly no longer in production) and marketed under the name "iBall". 

Mini Acoustic Levitator

Get this inexpensive device here:

From EngineDIY: BUY NOW: Mini Acoustic Levitator

Mini Acoustic Levitator: small pieces of styrofoam become trapped between areas of higher pressure induced by high frequency sound waves. Ultrasonic transducers placed at the top and bottom are basically speakers that emit sound waves at a frequency of 43,000 Hz, which corresponds to a wavelength of 8mm for dry air. If the transducers are positioned just right standing waves are produce with nodes of low pressure at half wavelength intervals- and low mass objects like these foam pellets will be suspended against gravity when placed near one of these nodes. Here we see a stack of three pellets with a spacing of about 4mm which is the expected distribution of the nodes. To place the pellets into the sound stream without disrupting the standing waves this device comes with a small screen with a handle which allows the sound waves to flow through the holes in the mesh and trap piece of foam. Although the device uses sound it appears silent as the frequency used is way above that which humans can hear (20Hz to 20kHz).

 


Precession of a Gyroscope

Get one here: 
From Amazon: BUY NOW Gyroscopes 
From eBay: BUY NOW Gyroscopes 

Precession of a Gyroscope: in defiance of gravity this gyroscope is supported only at one end. The physics and vector nature of angular momentum! Note that as friction slows the rotor of the gyroscope down, the precession rotation rate gets faster and faster. After some energy loss the gyroscope contacts the table and vibrations move the unit around while the angular momentum maintains its orientation. 

Color Flame Candle Spectrum

Color Flame candles available here:
From Amazon: BUY NOW: Color Flame Birthday Candles

Get the diffraction grating used in the video here:
From Amazon: BUY NOW: Diffraction Grating

or paper glasses version as party favors!
From Amazon: BUY NOW: Diffraction Glasses

Color Flame Birthday Candle Physics: the colored parts of these candle flames are due to excitation of specific chemical elements mixed into the wax. When viewed through a diffraction grating some of the prominent emission frequencies (electrons jumping between quantum energy levels) can be seen as “ghost” images to the side as the grating separates the light into the spectrum emitted by each flame. Most notably the yellow candle has a strong yellow/orange emission line from sodium, the red candle has similarly strong red and orange lines from strontium, and the blue and green candles have a bunch of overlapping violet/blue/green lines from copper and probably potassium. Note that glowing tip of the wick creates a thin line of the full continuous spectrum. 

Spinnobi Springy Spinner 

Get one here! 

From Amazon: BUY NOW: Spinnobi Spinner

Spinnobi: a spinner with bounce! With springs mounted along the axis on both sides of the dense rotating silicone disk, this spinner demonstrates gyroscopic stability- keeping its orientation as it falls and bounces. Conservation of angular momentum on display with this improved take on the spinner.


Rheoscopic Sworld

Get a Sworld ball (choose a color) here:

From Amazon: BUY NOW: Sworld Rheoscopic Ball

Also- the best in rheoscopic kenitic art- see: the Vortex Dome

Rheoscopic Sworld: this nice example of fluid flow kinetic art uses rheoscopic fluid encased in flexible bubble of plastic to reveal the intricate motion of turbulence. A suspension of tiny flat mica crystals tend to align themselves at the boundaries where the fluid is moving comparatively faster or slower, making the typically invisible flow patterns visible. 

Well Balanced Cabernet

Similar wine racks available here: 
From Amazon: BUY NOW 
Balance Wine Rack 

Many well crafted versions avaulable here:
From Etsy: BUY NOW 
Wine Bottle Balance

Acrylic Wine Bottle Balance

Well Balanced Cabernet: a carefully engineered acrylic version of this famous demonstration- the center of mass of the rack/wine bottle system is directly over the base providing unstable equilibrium for this balancing act. Suspended here is Hypothesis by Roots Run Deep, an excellent Napa cabernet sauvignon. 

Magnetic Top and Snake

Available in a variety of styles: 
From eBay: BUY NOW Magnetic Top and Snake 

Magnetic Top and Snake: the magnetic tipped top stays on the perimeter of the steel snake (or is it a planarian?)- but since the top has much more mass, the snake moves the most slithering to and fro. This kinetic art toy has been around for decades and takes advantage of Newton's 3rd law and rotational kinetic energy. 


Oil Drop Timer

Get one here: 
From Amazon: BUY NOW Dolphin Timer 

Oil Drop Timer with Dolphins: immiscible fluids of different densities stay separate under gravity with the lightest density on top. The density of the plastic dolphins is greater than the density of the top fluid but less than the density of the bottom fluid, so they stay at the boundary in equilibrium. The dolphins have a metal weight in their tails so that the buoyant force will keep them upright even as the liquids trade places (2 minutes shown in time-lapse). Archimedes' Principal at work here at multiple levels. 

Pixelated Playing Cards

Available from these fine sources: 
From Amazon: BUY NOW Pixel Cards 
From eBay: BUY NOW Pixel Cards

Pixelated Playing Cards: what one sees is all about the lighting with this transparent deck of cards. When backlit these poker sized cards become simply a grid of dots- reminding us that what we see not only concerns the physical properties of the perceived object, but also the location of the light source and the frequency and intensity of its emissions.

Time's Up

Similar timers available from these sources: 
From eBay: BUY NOW 
Inverted Timer 


From Amazon: BUY NOW 
Inverted Timer 


Time's Up: inverse of the sandglass- tiny plastic beads are less dense than the water and thus ascend to the top of the container under the influence of a buoyant force in accordance with Archimedes' principle. This timer takes almost exactly 6 minutes to complete shown here at normal speed for the first half of this video, and the second half is condensed to 24 seconds in time-lapse. 


Van de Graaff Generator

This device is sold as the "Static Shocker" hands on lab. Get one here for $8.95! : 
From Educational Innovations: BUY NOW Static Shocker Mini Van de Graaff 

The device can use an empty aluminum can for the top electrode which works- but this $9 hollow steel sphere looks and works even better- I used the 80mm sphere: 
From eBay: BUY NOW Hollow Steel Sphere 

Van de Graaff Generator: this miniature electrostatic generator can create potentials of more than 50,000 volts allowing sparks to jump a couple centimeters through dry air. Similar physics to the sparks created when shoes scuff on carpet, a moving rubber dielectric belt carries electrons away from the top sphere leaving it positive charged- as can be seen by the electrostatic repulsion of some Mylar strands. A small battery powered 3V motor drives the belt via the bottom pulley in this unit that costs less than $10 US.?With appreciation to @educational_innovations for sending me this device! 

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.