@physicsfun Rattleback
Availble from STEMCell Science:
From Etsy: BUY NOW: @physicsfun Rattleback
Wood Rattleback: spin reversing toy where a complicated combination of friction, precession, and instability induced vibrations transforms the rotational energy into into rattling (energy of oscillations) and then back into rotational energy in the opposite direction. The induced rattling is primarily due to the asymmetric shape of the bottom, like that of a propeller. Note the toy reverses almost immediately when spun clockwise, however, as demonstrated on the 3rd spin, this design will also reverse if spun counterclockwise! The reversal in this mode takes place after a while and only a 1/4 turn or so, but is predicted by theory yet rarely seen. @physicsfun exclusive!
Uranium Glass Marbles
Available here:
From STEMCell Science: BUY NOW: Uranium Marbles
And get the 405nm Laser here:
From eBay: BUY NOW: 405nm Laser
Uranium Glass Marbles: the very small quantities of uranium oxide in this glass give it its green color and produces brilliant fluorescence under a 405nm violet laser pointer. Uranium is of course radioactive but the tiny amount in this kind of glass poses no risk. The florescence has nothing to do with the radioactivity- in fact it is myth that radioactive items glow!
Pentominoes 3 Color Challenge
@physicsfun exclusive design- available only from STEMCell Science:
From Etsy: BUY NOW: 3 Color Pentominoes Puzzle
Pentominoes 3 Color Challenge: fit all 12 pentominoes into a 6x10 rectangle such that no two identically colored pieces touch. Pentominoes are the set of all 12 possible arrangements of five identical squares joined edge to edge. Since 5x12=60, the pentominoes can tile a 6 x 10 rectangle with no gaps (there are 2339 ways to do this- yet even finding one solution is quite difficult). Adding the 3 color challenge reduces the number of possible solutions to just this one shown here! Made from laser cut acrylic and wood- and now available for the first time in a limited production run.
JSC-MARS-1 Martian Soil Simulant
Currently avaiable simulated martian regolith:
MMS-2 Mars Regolith Simulant developed by the Exolith Lab at University of Central Florida
From STEMcell Science: BUY NOW: Martian Soil Simulant Sample
JSC MARS-1 Martian Soil Simulent: what the rust colored dirt of the Red Planet would look like up close! Produced by NASA for engineering studies of future human activities on Mars, this simulated regolith closely approximates the chemical, mineral, and grain size distribution based on data from the Viking and Pathfinder landers.
JSC 1 Lunar Soil Simulant
Currently avaiable simulated lunar regolith:
LMS-1 Lunar Mare Simulant developed by the Exolith Lab at University of Central Florida
From StemCell Science: BUY NOW: Lunar Soil Simulant Sample
In the video: JSC-1 Lunar Soil Simulant- if you could scoop up a handful of the surface of the Moon, this is how it would look. Produced by NASA for engineering studies of future human activities on the Moon, the simulated regolith closely approximates the chemical, mineral, and grain size distribution found in actual lunar samples from the Apollo missions. Sourced from slightly porphyritic basalt ash sampled from craters near Flagstaff AZ and then processed. The LMS-1 Lunar Mare Simulant developed by the Exolith Lab is the latetest and most up to date version.
Acrylic Rattleback
These acrylic versions work great and are inexpensive:
From STEMCell Science: BUY NOW: Rattlebacks
Acrylic Rattleback: a favorite from my collection- prefers to spin counter clockwise. If spun clockwise, a complicated combination of friction, precession, and instability induced vibrations transforms the rotational energy into into rattling (energy of oscillations) and then into rotational energy in the opposite direction! This behavior is related to the asymmetric shape of the bottom of this kind of rattleback, it's somewhat propeller shaped with an "S" curve along the bottom ridge
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.
Earth Mass Black Hole
Precision machined tungsten alloy spheres avaulable here:
From STEMCell Science: BUY NOW: Tungsten Black Hole Replica
Earth Mass Black Hole: this sphere of tungsten alloy has a diameter of 17.7mm, a precision representation of the size of the event horizon of a black hole with a mass equal to that of the Earth! If the entire mass of the earth could somehow be compressed to the size of this sphere, it would indeed collapse to a black hole with an event horizon defined by a Schwarzschild radius of 8.87mm. For comparison a black hole with the mass of the sun would be 6km across. This black hole replica is made of one of the densest materials available, a tungsten alloy with ?=18.5 g/cm³ which produces a strange sensation when you hold it, with a weight of twice that of a ball bearing of equal size.
Earth Mass Black Hole with Space Warping Display Stand
Precision machined tungsten alloy spheres available here:
From STEMCell Science: BUY NOW: Tungsten Black Hole Replica
Earth Mass Black Hole: this sphere of tungsten alloy has a diameter of 17.7mm, a precision representation of the size of the event horizon of a black hole with a mass equal to that of the Earth! If the entire mass of the earth could somehow be compressed to the size of this sphere, it would indeed collapse to a black hole with an event horizon defined by a Schwarzschild radius of 8.87mm. For comparison a black hole with the mass of the sun would be 6km across. This black hole replica is made of one of the densest materials available, a tungsten alloy with ρ=18.5 g/cm³ which produces a strange sensation when you hold it, with a weight of twice that of a ball bearing of equal size.