Horizontal Hand Boiler
This device available here:
From Edicational Innovations: BUY NOW: Horizontal Hand Boiler
Horizontal Hand Boiler: liquid-gas phase transition. The boiling point of dichloromethane is slightly below body temperature and heat from a hand will induce vaporization of the liquid which increases pressure in one bulb pushing the red (dyed) liquid through the glass pipe to the other bulb. The process can repeat by switching the hand to the other side, but as both sides heat up the transfer is less vigorous. An inexpensive toy demonstrating phase changes and other thermodynamic physics.
Spring/Latch Polymagnets
Avilable here:
From Polymagnet.com: BUY NOW
Spring/Latch Pair Demo
Get some magnetic viewing film here:
From Educational Innovations: BUY NOW
Magnetic Viewing Film
From Amazon: BUY NOW
Magnetic Viewing Film
Spring Latch Polymagnets: this pair of coded magnets attract but don’t touch in a state of stable equilibrium at a distance of 1/2 cm- but if one magnet is turned a half twist they latch together. Magnetic viewing film reveals the specific and complex arrangement of N and S poles that allow for this set to act like a spring or a latch (although only if constrained to an axis along their centers).
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?
Birefringence in Calcite
Get a sample here:
From Amazon: BUY NOW Optical Calcite Crystal
From eBay: BUY NOW Optical Calcite Crystal
Get inexpensive polarizing filters here:
From Educational Innovations: BUY NOW Polarizing Filter Sheets
Birefringence in Calcite: the speed of light in a calcite crystal depends on polarization- the refractive index is different depending on the polarization orientation of the light transmitted through it. As a polarizing filter is rotated 90 degrees, one image appears and the other vanishes, showing that the polarization orientation of the light of the two images is indeed perpendicular. In addition the elegant rhombohedral nature of calcite crystals is obvious in this sample.
US Patriotic Radiometer
Radiometers are available from these sources:
From Educational Innovations: BUY NOW Radiometer
A wide variety available here, including some nice blown glass displays:
From Amazon: BUY NOW Radiometers
Hundreds of options on eBay:
From eBay: BUY NOW Radiometers
US Patriotic Radiometer: 4th of July physics toy on this 242th year since the the Declaration of Independence. Produced in the 1970s by Kyp-go (maker of Balafire bulbs) the images spin with kinetic energy converted from light. Light heats up the "vanes" which then heat up the very thin gas left in the bulb- the black side of the vane is hotter and any gas molecules that come into contact with it fly off at a faster speed imparting impulse to the rotor. Radiometers with special vanes like this are no longer in production but sometimes pop up for sale online as antiques.
Quantum Re-Excitation: Phosphorescence
Need a UV laser pointer? Get 3 lasers (one of each color) for under $10 (including S&H):
From eBay: BUY NOW red+green+blue(UV) laser pointers
Get inexpensive phosphorescent sheet material here:
From Educational Innovations: BUY NOW Glow-in-the-dark sheet
Quantum Re-Excitation: a green laser should not normally be able to induce a phosphorescent glow, but if the material is already excited a green laser can re-excite it as seen here. Glow-in-the-dark phosphorescence is a quantum mechanical phenomenon where high energy photons (like those from a near UV laser pointer) are absorbed by electrons which are then boosted to higher energy levels. The glow comes from these electrons emitting lower energy photons (green in this case) as they jump down through a series of energy levels back towards their ground state. If an electron is only partially down the cascade path, lower energy photons from a green laser can bump it back up to the excited state. Quantum mechanics is all about discrete jumps in energy like what is happening here.
Radiometer in Arylic
Similar vintage items can often be found on eBay (a bit pricey though):
From eBay: BUY NOW Radiometer in Acrylic
Regular radiometers are available from these sources:
From Educational Innovations: BUY NOW Radiometer
A wide variety available here, including some nice blown glass displays:
From Amazon: BUY NOW Radiometers
Hundreds of options on eBay:
From eBay: BUY NOW Radiometers
Radiometer in Arylic: kinetic energy from light in this Eames era vintage Lucite block sculpture with encased radiometer. Light heats up the "vanes" which then heat up the very thin gas left in the bulb- the black side of the vane is hotter than the colored side and any gas molecule that comes into contact with it flies off at a faster speed imparting impulse to the rotor.
Switch Pitch Ball
Get one here:
From Edicational Innovations: BUY NOW: Switch Pitch Ball
Switch Pitch Ball: this spherical assembly changes color by turning inside out when tossed into the air. A favorite of my mechanical toys with surprising physics. Interestingly the advertisements for this toy incorrectly claim air drag is involved in the transformation. To understand why the ball inverts first note that the ball is made of multiple components hinged together. In launching the ball from the hand an upward acceleration results in a torque that pivots each component around its center of mass, causing the rotation of these components in an organized way leading to the transformation. Imagine tossing a stick straight up. If the stick is perfectly vertical upon launch it will move straight up- but if it is initially slanted at all it will also begin to rotate upon launch. Similar physics underlies the motion of each component of the ball- shown here in 240 fps slow motion. The Switch Pitch is produced by the makers of the Hoberman Sphere.
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.
Tea Candle Steam Engine
Get one from these fine sources:
From Educational Innovations: BUY NOW Tea Candle Steam Engine
From Amazon: BUY NOW Tea Candle Steam Engine
Other interesting engines available here: Simple Heat Engines
Tea Candle Steam Engine: a functional piston steam engine complete with boiler and flywheel. Takes about 2 minutes to get going after the candle is lit. The invention that powered the industrial revolution on a desktop! Made by Wilesco.
Ooze Tube Viscosity Contrast
Many colors (and two sizes) to choose from:
From Amazon: BUY NOW Ooze Tube 3 Colors
From Educational Innovations: BUY NOW Ooze Tubes
Ooze Tube Viscosity Contrast: this set of ooze tube timers comes with 3 mixtures of polyisobutene fluid, each with a different viscosity where green always wins the race: green (thin), yellow (medium), and red (thickest). A curious periodicity in the rate of flow is related to the formation of non-spherical bubbles as the air and fluid trade places (an hour shown in time-lapse). The fluid also displays the “liquid rope-coil effect” where the fluid thread coils and stacks as it lands on the pooling surface.The physics of the liquid rope-coil effect is pretty complex. Here is a recent scientific paper on the topic with nice illustrations.
Journal of Fluid Mechanics: Multiple coexisting states of liquid rope coiling