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The Museum of Science, Art, and Human Perception
Bouncing Ball
The exhibit features a very massive block of concrete to provide inertia to the base:
Wikipedia has the details on the physics of bouncing objects.
And the Exploratorium "snack" on the application of this physics to sports: Bouncing Baseballs.
Bouncing Ball @exploratorium : a steel ball bounces more than 230 times (counted using slow motion video) before coming to rest in this exhibit demonstrating the physics of a high coefficient of restitution. The bottom plate is amorphous steel and attached firmly to a massive block of concrete to enable the ball to retain as much kinetic energy as possible after each collision. ? With special thanks to the Exploratorium!
Spindrift
See more photos and video of this exhibit at the artist's online gallery: Spindrift and other installations by Shawn Lani
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Spindrift @exploratorium: surprisingly complex and graceful motions arise when rings are set to roll on a parabolic surface in this exhibit created by artist Shawn Lani at the Exploratorium in San Francisco. As the energy of the ring's center of mass trades to and fro from potential to kinetic, odd motions such as flip-flops, figure eights, and quick spins can occur in a determined but chaotic fashion. ? With special thanks to the Exploratorium!
Turntable
Some interesting history of the Turntable, one of longest running exhibits at the Exploratorium.
Turntable @exploratorium : rolling disks on a spinning platform. The path of each disk depends on position and angle at launch. Interesting orbits result from the interplay of angular momentum and gravity in this interactive exhibit. ? With special thanks to the Exploratorium!
Magnetic Fluid Patterns
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Get your own ferrofluid display- Click on this link!
Magnetic Fluid Patterns @exploratorium: a dark ferromagnetic fluid, trapped in a small gap between two plates of glass, reacts under the influence of a powerful magnetic field in this exhibit at the Exploratorium in San Francisco. The intricate and beautiful fluid patterns result from surface tension between the liquids competing with the ferrofluid attempting to align with the field lines of a strong magnet as it is positioned at different distances underneath. ? With special thanks to the Exploratorium!
Pendulum Snake
This exhibit include labels for the exact period of each pendulum:
This Exploratorium "snack" describes how to build your own with simple supplies: Pendulum Snake
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Small versions you can buy are available here:
From Amazon: BUY NOW Pendulum Snake
Pendulum Snake- one of my favorite exhibits at @exploratorium: ten swinging spheres, the first has a frequency of 15 swings per 30 seconds, the second has 16 in the same time, the third has 17, up to the tenth with 24 swings per 30 seconds. If released at the same time and height the amazing patterns result as each independent pendulum goes in and out of phase with the rest. Note that for a pendulum the frequency of oscillation depends on the square root of its length. ? With special thanks to the Exploratorium!
Thermochromic Pencils
Visit the exploratorium: see some of my favorite exhbits here
Get similar pencils here: Thermochromic Pencils
Themochromic Pencils: some amazing pencils I found in the @exploratorium gift shop last week that exhibit reversible color change. The warm air from a hair dryer can quickly shift the color of these pencils, and then as they cool back to room temperature the original color slowly fades back in. The color change can also be achieved by body heat from the hand (swipe for demo). The color change seen here most likely employs leuco dyes, thermochromic chemicals that have two reversible forms, one colorless when warmed above a threshold temperature.
Water Spinner
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 @exploratorium : The parabolic surface of a contained liquid under the combination of centripetal acceleration and the pull of gravity. Centripetal acceleration increases proportional to the distance from the axis of rotation, so the liquid stacks highest far from the center. Also, a faster spin rate results in a deeper and steeper parabola- note how the surface flattens out as the exhibit comes to rest. Additional physics- symmetric waves (from the sharp initial impulse) travel and reflect along the curved surface for the first few rotations until damped out via viscosity and friction. ? With special thanks to the Exploratorium!
Magnetic Pendulum Array
Magnetic Pendulum Array @exploratorium: 21 aluminum pendulums, each with a large magnet affixed to the end. The magnets allow kinetic energy to be shared. Note how the energy of the end pendulum is transferred to the rest in two steps- 1) the magnetic fields interact to damp the motion until 2) the end pendulum is captured into synchronized motion with the rest, allowing the energy to propagate to the front pendulum. ? With special thanks to the Exploratorium!
Circling Wave Umbrella
Kinetic Art by artist in residence Ned Kahn
Circling Wave Umbrella @exploratorium: kinetic art that produces mesmerizing wave structure in a disk of fabric. Follow the white dot on the bottom of the fabric to see the actual rotation rate of the disk. The stretchy vinyl coated spandex is set to spin at about 60 RPM which sets up a dynamical interplay between the inertia of the fabric and air resistance, producing four waves that travel at about 20 RPM. Thus the waves rotate at about 1/3 the speed of the cloth. Similar rotational waves travel around the arms of galaxies! Created by Ned Kahn, long time artist in residence at the Exploratorium.?With special thanks to the Exploratorium!
Cosmic Rays in Cloud Chamber
The Cloud Chamber is one of the longest running exhibits at the Exploratorium, and one of my favorites.
Cosmic Rays in Cloud Chamber @exploratorium: Visualizing the invisible- we live in a constant rain of charged subatomic particles that pass through the atmosphere (and our bodies) at relativistic speeds. The fleeting white lines and streaks seen here mark the paths of these cosmic ray particles through amplification via a phase change. The cloud chamber, with refrigeration on the bottom and heater elements on top, creates a 10cm thick region of supersaturated alcohol vapor that is at a temperature below its condensation point. Energetic charged particles produce a trail of ions (atoms with an electron knocked off) and these ions become the center of the drops that form the white trails showing the path of the particles. ? With special thanks to the Exploratorium!
Sand Shaker
See more photos and video of this amazing exhibit at the artist's online gallery: Sand Shaker by Charles Sowers
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Sand Shaker @exploratorium: a thin layer of white sand is subjected to vibrations on top of a circular plate in this exhibit created by artist Charles Sowers at the Exploratorium in San Francisco. When granular substances like sand are rapidly shaken, they often take on the properties of fluids through a process called vibrofluidization. Strange non-Newtonian fluid behavior is seen in this sand when the frequency of vibration is adjusted to 16Hz (shown here in 240fps slow motion)- amazing complexity arising from simple and regular motion! ? With special thanks to the Exploratorium!
Slinky Treadmill
Learn more about the physics of the slinky here: Exploratorium Science Snack
The slinky has been a popular toy since 1945! Read about the history and physics of the slinky, and the naval mechanical engineer that invented it on Wikipedia.
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Slinky Treadmill by @exploratorium: kinetic motion energy transfers to elastic potential energy and then back to kinetic energy in a cycling process as a slinky spring "walks" down an incline. Put the system on a treadmill, such as this one at the Exploratorium in San Francisco, and the walking behavior can be explored for many minutes. Note that after a while the slinky's walking becomes erratic.? 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!
Sand Pendulum
Frank Oppenheimer, founder of the Exploratorium Museum, demonstrates the sand pendulum display in these images from the 1970s.
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Sand Pendulum @exploratorium: a swinging pendulum maps out a beautiful sine curve on to a conveyor belt. The belt moves at constant speed such that the sand creates a graph of the pendulum’s position as a function of time. With special thanks to the Exploratorium!
Zeeman Effect on Mercury Green Emission Line
Wikipedia has a nice introduction to the Zeeman Effect
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!
Drip Chamber
Another amazing creation by artist Charles Sowers:
See more photos of this installation and other amazing work via the artist's web page: Drip Chamber
Drip Chamber @exploratorium : viscous and transparent liquid glycerin forms into drips and lumps under gravity. Light rays form caustics (see previous post) that look like animated stars encased in geometric outlines from a bright light shining through from underneath. The star caustics occasionally wink to black as a drop detaches and falls in this kinetic art installation by Charles Sowers. ? With special thanks to the Exploratorium!
Water Spinner- Part 2
Read more about this exhibit here:
Exploratorium Science Snack: Water Spinner
Visit the Exploratorium
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!