All physicsfun toys

LASER Pointers + Diffraction Grating

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

Rainbow Symphony has a nice selection of diffraction gratings and sun catchers:
From Amazon: BUY NOW: Diffraction Grating Toys

LASER Pointers + Diffraction Grating: three frequencies of laser pointer- Red (635 nm), Green (532 nm), and Blue (450 nm). Note that the distance between the intensity maxima (bright spots) is greatest for the red (long wavelength) and closest for blue (shortest wavelength) with the green in between. The diffraction grating is the same form as one of those rainbow fireworks glasses- this one from has 13500 lines per inch. 

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.

Pendulum Snake

Get this version here:

From Amazon: BUY NOW: Pendulum Snake

Pendulum Snake: 15 independent swinging pendulums, each with a slightly longer period than the one to its left side, create mesmerizing wave patterns. As the pendulums get further out of phase with each other the waves become shorter and faster. This order and pattern is quickly destroyed if two of the pendulums were to collide (swipe for demonstration).

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.

Hyperbola Clock

This amazing clock available here: 
From Etsy: BUY NOW Hyperbola Clock

From Amazon: BUY NOW: Hyperbola Clock

Hyperbola Clock: a straight rod glides through a curved hole in this unconventional clock based on the hyperboloid, the 3D ruled surface traced by rotating diagonal line. In this creation by Robert Darwen of Fibonacci Clocks, the rod serves as the hour hand with a smaller minute hand above the center of the base disk. (The time adjustment dial of the clock mechanism was connected to a small motor to produce the sped up motion in this video so that 1 second = 1 hour) 

Nova Plexus Interlocking Puzzle

Precision machined and available in brass or stainless steel:

From Art of Play: BUY NOW: Nova Plexus Puzzle

Nova Plexus Puzzle: 12 identical brass rods can create 4 interlocking triangles in a perfect symmetry- look carefully and you can see that each rod is in an identical configuration with the 5 others that connect with it. Precision machined notches on the ends of the rods allow them to interlock with elastic tension such that vector sum of the 5 forces on each rod is zero- creating this astonishing geometry as the equilibrium state. Unlock the ends of any two rods and the system instantly disassembles (swipe to view process in slow motion). Invented/designed by artist and computer scientist Geoff Wyvill in 1978, this puzzle has just recently been made available for sale with a limited production run.

Countdown Dice

Get a set here:

From The Dice Lab: BUY NOW: Countdown Dice

Countdown Dice: roll these d24 dice carefully and the number on the top surface will count up or count down in sequence! The geometric form that allows this behavior is called a sphericon, a convex solid discovered by David Hirsch that has the properties of a developable roller, a shape where every part of its surface makes contact with the plane on which it rolls. Another unique and interesting die design by Henry Segerman and The Dice Lab.

Reuleaux Rotor

This toy is availble from Amazon Japan and will ship to the US:

From BUY NOW: Reuleaux Rotor Wodden Toy

Reuleaux Rotor: this famous curve of constant width, the Reuleaux triangle, can rotate such that at all times it remains in contact with all four sides of a square. As demonstrated by this wooden toy from Japan, the rotor covers approximately 98.77% of the area of the square, missing only the sharp corners. The curves in the corners are in the shape of an elliptical arc. Fun fact: a Reuleaux triangle has a perimeter equal to pi times its width- just like a circle!