Exothermic Crystallization Heat Pack
Available in many sizes and colors:
From Educational Innovations: BUY NOW Click Activated Resuable Heat Pack
From Amazon: BUY NOW Click Activated Reusable Heat Pack
Note: this site contains affiliate links for which I may be compensated
Exothermic Crystallization Heat Pack: real-time instant crystallization of a supercooled solution. Solid sodium acetate melts at 137F (58C), but it will stay in liquid form as it cools to room temperature creating a supersaturated and supercooled state- the solution stays in the liquid form until a seed crystal, provided by clicking the metal disk, initiates the solidification. The resulting white crystal is actually quite hot; solid states have lower energy than liquid states and thus the difference in energy is given up as heat that raises the temperature back up to the melting temp, and you can see in the few seconds of the video that the temperature rises from 26C to 34C. This pack is reusable many times- just boil the pack until all the crystal is melted to reset.
Revolution
This vintage toy can sometimes be found on eBay.
Quality models of the modern version of this physics toy are still available
From Educational Innovations: BUY NOW Magnetic Levitator
From Amazon: BUY NOW Magnetic Levitator
Note: this site contains affiliate links for which I may be compensated
Revolution: vintage 2D magnetic levitation- permanent magnets can only produce static equilibrium along two dimensions- here a glass mirror constrains the third dimension, and makes for a nice bearing surface for rotation. This item was sold in the 1990s in mall shops such as Natural Wonders.
Tea Candle Steam Engine
Get one from these fine sources:
From Educational Innovations: BUY NOW Tea Candle Steam Engine
From Amazon: BUY NOW Tea Candle Steam Engine
Other interesting engines available here: Simple Heat Engines
Note: this site contains affiliate links for which I may be compensated
Tea Candle Steam Engine: a functional piston steam engine complete with boiler and flywheel. Takes about 2 minutes to get going after the candle is lit. The invention that powered the industrial revolution on a desktop! Made by Wilesco.
Spring/Latch Polymagnets
Avilable here:
From Polymagnet.com: BUY NOW
Spring/Latch Pair Demo
Get some magnetic viewing film here:
From Educational Innovations: BUY NOW Magnetic Viewing Film
From Amazon: BUY NOW Magnetic Viewing Film
Note: this site contains affiliate links for which I may be compensated
Spring Latch Polymagnets: this pair of coded magnets attract but don’t touch in a state of stable equilibrium at a distance of 1/2 cm- but if one magnet is turned a half twist they latch together. Magnetic viewing film reveals the specific and complex arrangement of N and S poles that allow for this set to act like a spring or a latch (although only if constrained to an axis along their centers).
Hand Boiler
A variety of shapes and colors are available
From Educational Innovations: BUY NOW Hand Boilers
From Amazon: BUY NOW Hand Boilers
Note: this site contains affiliate links for which I may be compensated
Hand Boiler: liquid-gas phase transition. The boiling point of dichloromethane is slightly below body temperature - heat from a hand increases pressure in the bottom bulb pushing the purple (dyed) liquid through the glass pipe to the top.
The PhiTOP
Get one here!
From Educational Innovations: BUY NOW PhiTOP
From Amazon: BUY NOW PhiTOP
Note: this site contains affiliate links for which I may be compensated
The PhiTOP: spinning things often have surprising physics! This unique top is made of solid aluminum in the shape of a prolate elIipsoid- and the name of the top is derived from the following design requirement: the ratio of the semi minor (short) axis to the semi major (long) axis is made equal to the mathematical constant the golden ratio φ (phi). Invented by astrophysicist Kenneth Brecher, this top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippy-top.
Drinking Bird Heat Engine
Get this famous physics toy from these sources:
From Educational Innovations: BUY NOW Drinking Bird Engine
From Amazon: BUY NOW Drinking Bird Engine
Note: this site contains affiliate links for which I may be compensated
Wikipedia has wonderful details about the rich history (and further descriptions of the operational principals) of the Drinking Bird.
Drinking Bird Heat Engine: time lapse of 15 minutes into 15 seconds (4 cycles). Cooling by evaporation at the head leads to lower pressure in the top bulb, the dichloromethane fluid rises up the neck making the bird top heavy and the bird tips over dipping its beak and letting the fluid return to the bottom bulb. The time lapse allows a clearer picture of how the fluid rises, shifting the center of mass, and how tipping makes the glass column lift out of the fluid in the bottom allowing the pressure to equalize and letting gravity pull the fluid to return to the base. Process repeats as long as the top stays wet. So much physics in one hypnotic toy!
Memory Spring
Available here:
From Mindsets: BUY NOW Memory Springs
Affordable samples and kits here:
From Educational Innovations: BUY NOW: Energy Wire
Similar produces featuring Nitinol Memory Wire:
From Amazon: BUY NOW Nitinol Memory Wire Kits
Note: this site contains affiliate links for which I may be compensated
Memory Spring: some special alloys of brass can be made to have a shape memory triggered by temperature. These springs quickly change their length from 1 cm to 2.5cm when heated above 90 C (done here with hot water) and just as quickly shrink back to original size when cooled (immersed in cold water). Useful in many applications, especially things like automatic fire sprinkler valves and thermostats in car engines. This amazing property is related to a solid state phase transition similar to that of Nitinol wire called a Martensitic transformation.
The PhiTop
This great little lab stirrer (which I modified to have a transparent top) can be used in many investigations and demonstrations:
From Amazon: BUY NOW Magnetic Stirrer
Inexpensive concave lenses make great spinning platforms- get one here:
From Amazon: BUY NOW Concave Lens Spin Station
Get a PhiTOP in aluminum here (will work nicely in this demo):
From Educational Innovations: BUY NOW PhiTOP
From Amazon: BUY NOW PhiTOP
Note: this site contains affiliate links for which I may be compensated
Induced Current Spin-Up: Spinning magnets from the magnetic stirrer induce electric currents to flow in the brass PhiTOP- these currents then create their own magnetic field which opposes the magnets underneath and pushes the PhiTOP to spin. Credit to astrophysicist Kenneth Brecher, the creator of the PhiTOP and this unique means of using Lenz’s Law to spin it up. This top stands up vertically (when spun with sufficient rotational velocity) due to physics similar to that of the tippe-top. The concave lens keeps the top from wandering off of magnetic stirrer.
Buoyancy Discrepant Event
Samples available here:
From Educational Innovations: BUY NOW Ironwood Samples
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Buoyancy Discrepant Event: wood that sinks and a rock that floats!- a study in density properties of ironwood and pumice.
Mega Tippe-Top
Here is the mega tippe-top compared to typical tippe-tops on the market and a US quarter dollar:
Limited quantities available from the Spinning Top and Yo-Yo Museum of Burlington, Wisconsin
Educational Innovations has reasonably priced wood tippe-tops in their shop:
From Educational Innovations: BUY NOW Tippe-Tops
From Amazon: BUY NOW Tippe-Tops
Note: this site contains affiliate links for which I may be compensated
Mega Tippe-Top: spinning things often have surprising physics. This giant version of the famous flip-over top must be launched with a string pull to give it enough rotational energy to make the flip. It is also placed on a concave mirror to keep it from wandering too far. Friction with the mirror provides a torque that acts on the existing angular momentum of the top to flip it over.
Happy/Sad Spheres
Get a set here:
From Educational Innovations: BUY NOW: Happy/Sad Balls
Note: this site contains affiliate links for which I may be compensated
Happy/Sad Spheres: one ball bounces the other stops dead. The bouncy ball is made of neoprene rubber and exhibits high elasticity. The "sad" ball is made of polynorbornene and converts almost all kinetic energy into heat and sound- approximating/demonstrating the case of a completely inelastic collision. Polynorbrene is used in vehicle bumpers, for soundproofing, vibration damping, and other applications where recoil motion is unwanted.
Pencil Hyperboloid
Choose your color and get one here:
From Etsy: BUY NOW
Hyperboloid Pencil Holder
don't forget a set of pencils:
From Amazon: BUY NOW
Colored Pencil Sets
Note: this site contains affiliate links for which I may be compensated
Better yet- get some thermochromic color changing pencils!
From Educational Innovations: BUY NOW
Heat-Sensitive Pencils
Pencil Hyperboloid: a perfect gift for any math teacher- the precisely oriented holes in this base direct 16 pencils to reveal a hyperboloid, the 3D surface traced by revolving a diagonal(skew) line, the outline of which is the conic section of the hyperbola. A doubly ruled surface for any desktop!
Poly acrylamide Polymer Vanishing Act
Get some of these grow-spheres here:
From Educational Innovations: BUY NOW Growing Spheres
From Amazon; BUY NOW: Water Beads
Note: this site contains affiliate links for which I may be compensated
Poly-acrylamide Polymer Vanishing Act: these spheres of hydrophilic polymer have an almost identical index of refraction as that of water- thus when submersed they become invisible. Note the elasticity of these spheres from the way they bounce, while at the same time they refract their surroundings as a spherical lens. The super absorbent spheres start as hard crystals with a radius of 2mm and grow to 11mm when immersed in water. So much physics going on here!
Tiny Tippe Top
Available from this shop in Germany:
From experimentis-shop.de: BUY NOW Tiny Tippie-Top
From Amazon: BUY NOW Tippe-Tops
Note: this site contains affiliate links for which I may be compensated
Tiny Tippe-Top: spinning things often have surprising physics! The smallest functioning version of the famous flip-over top I've ever seen. Friction with the mirror provides a torque that acts on the existing angular momentum of the top to flip it over. The top will stay flipped until the spin rate slows down enough to where its center of mass pulls it back to the resting position.
Ooze Tube
Many colors (and two sizes) to choose from:
From Amazon: BUY NOW Ooze Tube
Note: this site contains affiliate links for which I may be compensated
The physics of the liquid rope-coil effect is pretty complex. Here is a recent scientific paper on the topic with nice illustrations.
Journal of Fluid Mechanics: Multiple coexisting states of liquid rope coiling
Ooze Tube: viscous polyisobutene fluid timer toy. Some interesting physics phenomena are found in this kinetic art novelty item: the "liquid rope-coil effect" where the fluid thread coils and stacks as it lands on the pooling surface, and a curious periodicity in the rate of flow that is related to the formation of non-spherical bubbles as the air and fluid trade places (shown in time-lapse). The physics of the coiling effect is complex (see the link in my blog). Broadly speaking the coiling is due to the bottom of the fluid rope widening at the contact point with the surface, and as it widens the fluid slows down but not evenly. This uneven rate of flow produces a bend and the elasticity of the stream constrains the rope to a limited radius- hence a stack of coils.
Poly Density Puzzle
Get the kit here:
From Educational Innovations: BUY NOW Polydensity Bottle Kit
Note: this site contains affiliate links for which I may be compensated
Folow the link above for details of the physics explanation.
Poly Density Puzzle: my favorite science brain teaser– white beads and blue beads “float” oddly separated beneath the surface of a clear liquid. If the contents are mixed by shaking the container, the white beads gather at the top and the blue sink to bottom! Adding to the mystery- within about 30 seconds the two layers of beads will slowly moved back to the middle. If you haven’t seen this demonstration before, what is your guess as to the physics behind this behavior?
Magnetic Field Viewer
Get one here:
From Educational Innovations: BUY NOW Magnetic Field Viewer Cube
From Amazon: BUY NOW Magnetic Field Viewer
Note: this site contains affiliate links for which I may be compensated
Magnetic Field Viewer: visualizing the invisible- tiny iron filings suspended in viscous oil gracefully chain up along the magnetic field lines of the ferromagnet, revealing its dipole configuration.