Craft sticke work great:
From Amazon: BUY NOW: Stick Bomb Supplies
Amazingly: There is a Wikipedia entry on Stick Bombs and their physics
Popsicle Stick Bomb: a form of simple tensegrity, the elastic potential energy of the bent sticks is dramatically released under application of a slight concussive force such as an impact with a table top- shown here in forward and backward slow motion (swipe to see three more explosions). Shown here is one of the simplest constructions with 5 flat sticks woven into a spring-loaded configuration held in place by friction and tension induced by the bending of the wood. A nice demonstration of energy conversion- potential to kinetic.
This device is sold as the "Static Shocker" hands on lab. Get one here for $8.95! :
From Educational Innovations: BUY NOW Static Shocker Mini Van de Graaff
The device can use an empty aluminum can for the top electrode which works- but this $9 hollow steel sphere looks and works even better- I used the 80mm sphere:
From eBay: BUY NOW Hollow Steel Sphere
Van de Graaff Generator: this miniature electrostatic generator can create potentials of more than 50,000 volts allowing sparks to jump a couple centimeters through dry air. Similar physics to the sparks created when shoes scuff on carpet, a moving rubber dielectric belt carries electrons away from the top sphere leaving it positive charged- as can be seen by the electrostatic repulsion of some Mylar strands. A small battery powered 3V motor drives the belt via the bottom pulley in this unit that costs less than $10 US.?With appreciation to @educational_innovations for sending me this device!
Get the classic here:
From Amazon: BUY NOW Mini Slinky
Get a giant version of the slinky here!
From Educational Innovations: BUY NOW Giant Slinky: Super Wave Spring
How a Slinky Falls: amazing physics demonstration with this classic toy. The center of mass of the slinky spring falls with an acceleration of g- note in this slow motion video that the bottom of the slinky does not move until the spring is fully collapsed. Hooke's law plus gravity!
Available from Pyrigan & Co.
From Etsy: BUY NOW: Lissajous Roller Illusion
From ShapeWays: BUY NOW: LIssajous Roller Illusion
Lissajous Roller: when viewing this 3D printed object from the side one sees a projection of a 3:2 Lissajous curve, but the object is actually cylindrical in frame and can roll towards or away from the viewer. When in motion a “dual axis illusion” is produced where the object appears to be rotating about a vertical axis. Invented by Bill Gosper and produced by Pyrigan & Co.
The nested curves revealed with this device are related to the Lissajous curves.
Learn more on Wikipedia: Lissajous curve
Scrap Metal Kinetic Sculpture: a bent spring becomes a coupled harmonic oscillator with two modes of oscillation, one along a horizontal direction and one at an angle. As the kinetic energy trades back and forth between these two modes the end of the spring traces out a Lissajous curve (revealed by a white LED) which gets smaller in size each cycle as friction dissipates energy from the system. The full beauty of this motion is captured by recording the light traced using the Slow Shutter Cam App which unveils the nested family of curves.($1.99 in App Store, Cogitap Software)
Guage block sets can be a bit pricy, but some fairly inexpensive pieces and small sets can be found for demonstrations and such:
From Amazon: BUY NOW: Gauge Blocks
Wikipedia has a nice description of Gauge Blocks and the Phenomenon of Wringing
Wringing Gauge Blocks: two blocks of metal (not magnets!) will stick together by a process called wringing if their surfaces are flat to high precision- such as these gauge blocks found in most machine shops. Here two blocks are forced apart with a snap, and then wrung back together with the characteristic sliding motion technique. Gauge blocks are flat to less that one millionth of a meter and are used by machinists for precision length measurements and calibration. The science of the wring force remains somewhat a mystery and no one has yet found a fully excepted physics description- but we do know that blocks will wring in a vacuum and that the force can be up to 30 times that of weight of the blocks. Fun physics from the shop!
This inexpensive electrophorus set works great!
From Amazon: BUY NOW Electrophorus Demonstration Set
The container is just the middle part cut from a plastic water bottle, and the "hail" stones are Styrofoam craft beads:
From Amazon: BUY NOW Styrofoam Craft Beads
For Volta's Hailstorm to work, the beads must be coated with a conducting spray (here is what I used):
From Amazon: BUY NOW Staticide Spray
Wikipedia has a very nice description of the physics of the Electrophorus and how it is used to transfer electric charge.
Volta’s Hailstorm and Electrophorus: electrical forces due to electrostatic charge send foam beads flying in this version of the historic demonstration by physicist Alessandro Volta. The beads are covered with an electrically conductive coating allowing them to transfer charge from the environment to the plate of the electrophorus. The acrylic platform becomes negatively charged when rubbed with a paper napkin, but it is also an insulator so the charge on it can not flow on to the aluminum plate of the electrophorus. Instead the charge on the platform pushes electrons to the top of the plate (like signs repel) and touching the plate results in a spark that removes the electrons giving the plate a significant positive charge that will then attract the beads.
This Simpson's themed wave machine was made back in 1999-2000 and is hard to find. Here is a fairly inexpensive wave machine that has a similar base mechanism:
From eBay: BUY NOW Liquid Wave Machine
Surf's Up Wave Machine: Bart rides a surfboard between two immiscible liquids which are sorted under gravity by density with the densest (dyed water) on the bottom and the lightest (mineral oil) on top. Bart’s board has a density between that of the two liquids so it stays at the boundary layer, and a capsule of air above Bart’s head keeps him upright. The motorized rocking mechanism in the base is powered by one C cell battery and produces the waves at the boundary layer by sloshing and colliding the dense liquid off each end. Found this rare 1999 toy on eBay.
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.
The bottle used here is from Voss Water: a nice cylinder and the labels come off easily. Amazon has the ingedients:
From Amazon: BUY NOW
acetone, blue glitter, food coloring, Voss Water
The density column I made for this video is based on blend of two ideas: this "science snack" from the exploratorium: Klutz-Proof Density Column and this ChemED X post: Blog of Prof. Tom Kuntzleman
See my Salt Fractionation post for details.
Unmixing Density Column: three liquids that won’t stay mixed! Acetone (dyed blue) floats on top of the higher density vegetable oil, which in turn floats atop salt water (dyed orange) which is more dense than oil. Acetone usually dissolves in water through hydrogen bonding interactions, but solubility can be altered. In a process called “salting out” a sufficient amount of salt is dissolved such that the water molecules, which are much more attracted to the resulting Na+ and Cl- ions (through ion-dipole bonds), will then ignore the weaker acetone hydrogen bonds. This results in the spontaneous separation of these three liquids no matter how well shaken up.
Available for all the planets and several versions of Earth:
From Amazon: BUY NOW
Mova Globes: all types
From Amazon: BUY NOW
Mova Globes: 1790 Terrestrial
From eBay: BUY NOW
Mova Globes: all types
Octopus Stand (in stock now!) available here:
From Etsy: BUY NOW
OctoStand in Metal
1790 Terrestrial Globe by Mova: rotating counterweighted globe sealed within a clear liquid filled acrylic sphere. The rotation in a Mova globe is powered by light that shines through the semi-transparent map image on to solar cells within the globe which drive a motor. But what does the motor push against to maintain the rotation? Believe it or not it uses magnets to push against the Earth's magnetic field like a compass needle. Wonderful physics of all kinds in the design of this clever device. The featured map is a faithful recreation of a globe famous for its accuracy at the time by Giovanni María Cassini and highlights the voyages of James Cook.