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Water Spinner- Part 2

Read more about this exhibit here: 
Exploratorium Science Snack: Water Spinner 

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For those that want the math! 
A youTube tutorial Spinning Water: The Mathematical Explanation

Water Spinner- Part II @exploratorium : a pair of waves (from the initial impulse) travel along the parabolic surface of the contained liquid, creating temporary peaks and valleys as they constructively and deconstructively interfere. As seen here in 240 fps slow motion, the symmetric waves travel and reflect along the curved surface for the first few rotations until damped out via viscosity and friction. See last Friday's post for more details about this amazing exhibit. ? With special thanks to the Exploratorium! 

Oil Drop Cascade

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Oil Drop Cascade @exploratorium : interplay of surface tension and gravity bend oil drops into strange shapes as they move through a grid of obstacles in this kinetic art toy. Like other oil drop timer toys, the colored oil will not mix with the clear kerosene liquid. Available at the Exploratorium gift shop. ? With special thanks to the Exploratorium!

Zeeman Effect on Mercury Green Emission Line

Wikipedia has a nice introduction to the Zeeman Effect 

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Zeeman Effect on Mercury Green Emission Line @exploratorium: directly explore the Quantum Mechanics of electron spin with this amazing interactive exhibit. Excited Mercury gas emits a bright green line at 546nm (seen here as concentric circles using a Fabry-Perot interferometer) due to electrons transitioning between the quantized energy levels. We learn in chemistry that electrons come two to a shell with opposing spins (Pauli Exclusion). Indeed when the excited Mercury tube is placed in between magnets the green line splits, demonstrating that the electrons now have slightly different energies corresponding to the spin orientations interacting with the magnetic field. Advanced level quantum phenomena in a museum exhibit! ?With special thanks to the Exploratorium! 

String Hyperboloid

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This exhibit reminds me of an amazing geometric sculpture where I used to work: Tractricious by Robert Wilson, founding director of Fermi National Accelerator Lab 

Click this link for inexpensive hyperboloids you can own! 

String Hyperboloid @exploratorium : 26 strings held straight by hanging weights can be rotated as a set to produce a hyperboliod- the quadric surface related to the revolution of hyperbola around its axis of symmetry. Note that although this 3D shape is curved, an a infinite set of straight lines (like those of the strings) lie on its surface. Turning the top disk of this exhibit raises the weights on each string so that when it is released the potential energy will transfer back and forth to kinetic energy of rotation until the energy is damped out due to friction. ? With thanks to the Exploratorium!

Monochromatic Room

The light source in this exhibit produces a frequency at 589nm 
Wikipedia has a nice description of the physics and applications of Sodium Vapor Lamps 
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Monochromatic Room @exploratorium: a photo of colorful San Francisco is illuminated by a very narrow frequency band of light, with a wavelength of 589nm- the characteristic spectrum of sodium vapor lamps at low pressure. Seeing color is both about the source of illumination and how an object interacts with light. Here a white LED flashlight can momentarily “paint” the scene with color. Sodium vapor lights are a type of gas-discharge lamp that uses sodium metal vapor in an excited state with two dominant spectral lines at 589.0 and 589.6nm, producing the bright yellow light in this exhibit. ? Thanks to the @exploratorium

Icy Bodies

Another amazing creation by artist Shawn Lani-- Icy Bodies has been installed at 13 science museums around the world: 
See the Shawn Lani Studios website for more details- and make sure to see the exhibit in person! 

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Icy Bodies @exploratorium: exquisitely beautiful and dynamic interactions between small chunks of dry ice and a shallow layer of water play out in this exhibit created by artist Shawn Lani at the Exploratorium in San Francisco. Frozen carbon dioxide (dry ice) is denser than water, but the small pieces do not sink- instead each piece, at −78.5 °C, becomes encapsulated in a shell of ice that then floats. As the dry ice sublimates from a solid directly into a gas, jets stream from holes and fractures in the ice shells propelling and spinning the bits upon the water's surface. Droplets condense out of the air forming a cloudy mist in the vicinity of the cold gas jets which is lighted from the side to dramatic effect. ? With special thanks to the Exploratorium!

Dancing Drops

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Dancing Drops @exploratorium: an exhibit employing the Coandă effect on water droplets -an air stream attaches and wraps around the drops temporarily trapping them. As the air changes direction to flow around a drop, momentum is imparted to it pushing the drop against gravity. Constrained mostly by surface tension, under these conditions the water drops also have irregular and changing shapes leading to erratic motions in the uneven airstream.? With special thanks to the Exploratorium! 

Kinetic Rubin Vase

More ambiguous foreground-background illusions at the Exploratorium: 
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Kinetic Rubin Vase @exploratorium: spin this ceramic version of the Rubin Vase illusion and the white background transforms to two people talking. Entitled "Talking Face to Vase" this kinetic art is a permanent installation at the Exploratorium museum in San Fransisco that features the physics and psychophysics of vision and perception. The vase demonstrates the figure-ground distinction made by the brain- is it a vase, or two faces in profile? ? With special thanks to the Exploratorium. 

Convection Currents

Learn more about this exhibit here: 
Convection Currents Exhibit 

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Convection Currents @exploratorium : intricate and delicate structures called schlieren emerge in convective heat flow as hot, less dense water rises off of an electric heating element. A spot light shines through a thin glass walled tank of water with the L-shaped heating element immersed. The convective flow casts a shadow because the index of refraction of water is temperature dependent, with n decreasing at higher temperatures. Buoyancy, turbulence, heat transfer, physical optics- so much physics behind these mesmerizing patterns! ? With special thanks to the Exploratorium! 

Fresnel Mirror Array

"All Eyes om Me" Exhibit 
The physics and design of this exhibit is very similar to what is depicted in this image: 
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Fresnel Mirror Array @exploratorium : 360 mirrors arranged to reflect to a single focal point in this exhibit entitled “All Eyes on Me”. A mirror version of the Fresnel lens, where each concentric ring of mirrors is slanted toward the center, with the lager rings slanted more, such that the full assembly acts like a parabolic mirror.?With special thanks to the Exploratorium! 

In-Feed Google 2

In-Feed Google

Dual Axis Sand Pendulum

Available in many styles and colors: 
From Amazon: BUY NOW Sand Pendulum 
From eBay: BUY NOW Sand Pendulum  

Dual Axis Sand Pendulum: the kinetic energy trades back and forth between swinging toward the support arm and then swinging perpendicular to that path tracing Lissajous figures in the sand. The sand slowly dissipates the energy and the traced figures get smaller so the next one fits inside the last. Coupled oscillations like this can occur when multiple modes of motion (degrees of freedom) are available to the system.