Budget physics

Thermochromic Safety Sticker

These stickers transition back and forth and can be used on many surfaces. Get some here:

From Etsy: BUY NOW: Thermochromic Saftey Sticker

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Thermochromic Safety Sticker: the liquid crystal ester dye in this reusable sticker is calibrated to change color when the surface temperature exceeds 50°C (122°F)- that at which prolonged contact (more than 0.5s) will burn skin. Here the safety sticker is attached to a slab of aluminum and heated with a simple candle- it took about 3.5 minutes for the heat to distribute and bring the aluminum to the threshold temperature. When the surface cools the sticker again appears blank and can transition over and over again

Micro Racer in a Glass

These micro racer cars are sold under many brand names, and most come with a clear sphere to demonstrate this centripetal acceleration phenomenon. 

From Amazon: BUY NOW: Micro Racer + Sphere

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Micro Racer in a Glass: This tiny battery powered car overcomes gravity through centripetal acceleration and slight friction with the glass surface. With sufficient velocity the surface normal force supplies the centripetal acceleration. The car’s battery last for many minutes and is USB rechargeable.

Dudeney's Dissection 3D Print

Get this set here!

From Etsy: BUY NOW: Dudeney's Dissection 3D Print

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Dudeney's Dissection: an equilateral triangle canbe cut (dissected) into four pieces that will then assemble into a square. This 3D printed version comes as a puzzle- fit the pieces in each of two containers- a square and a triangle, which also makes it clear the two supplied shapes are of equal area. Fun fact: It is not known if a similar three piece dissection is possible. Also called Haberdasher's problem and described in 1907 by Henry Dudeney it is the only 4 piece solution known.


Sprial Oil Drop Timer

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From Amazon: BUY NOW: Oil Drop Timers

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Spiral Oil Drop Timer: when this drop timer achieves its steady state the drops form with amazing regularity in terms of both the size of the drop and the spacing between drops. The physics of immiscible liquids, surface tension, viscosity, and gravity combine to produce these interesting patterns. 

 

Hydrophobic Water Maze

Wonderfully well crafted and available from this shop :
From Etsy store TheSmallestWorkshop:

BUY NOW Hydrophobic Water Maze

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Hydrophobic Water Maze: a superhydrophobic coating allows this dynamic puzzle to use a drop of water as the "pinball", which can split into multiple smaller drops and recombine along the way. The wood surface is treated with silica nano-coating that makes water roll off- a condition sometimes referred to as the Lotus effect because leaves of the Lotus plant have this property.


Van de Graaff Generator

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 

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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! 

Magnetic Chaotic Pendulum

Currently available here: From Amazon: BUY NOW Magnetic Chaotic Pendulum 

Chick here for similar chaotic systems

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Magnetic Chaotic Pendulum: adding magnetic forces to gravity gives this pendulum chaotic motion- not random, but very sensitive to slight differences in initial launch conditions. Arranging the dipoles magnets on the base leads to different patterns of motion- here the center magnet attracts and the rest are set to repel. ROMP pendulum by Hog Wild toy company. 

Reverse Cartesian Diver

Glass divers available here: From Amazon: BUY NOW Glass Divers 

The reverse diver needs a bottle with a oval shaped cross section. I used the bottle from this product- it has the right shape and size and the label comes off easily: 
 
From Amazon: BUY NOW Oval Shaped Bottle Source 

Inexpensive and fun diver kits available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 

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Wikipedia has the details on the Cartesian diver (and reverse diver)

Reverse Cartesian Diver: physics puzzle (swipe for hint). On the left is a Cartesian diver- pressing on the bottle forces water into the glass diver, which then compresses the bubble in diver’s head allowing it to sink. On the right is a reverse Cartesian diver- again the bottle is pinched but this time the diver ascends- why? 


Switch Pitch Ball

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From Edicational Innovations: BUY NOW: Switch Pitch Ball

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Switch Pitch Ball: this spherical assembly changes color by turning inside out when tossed into the air. A favorite of my mechanical toys with surprising physics. Interestingly the advertisements for this toy incorrectly claim air drag is involved in the transformation. To understand why the ball inverts first note that the ball is made of multiple components hinged together. In launching the ball from the hand an upward acceleration results in a torque that pivots each component around its center of mass, causing the rotation of these components in an organized way leading to the transformation. Imagine tossing a stick straight up. If the stick is perfectly vertical upon launch it will move straight up- but if it is initially slanted at all it will also begin to rotate upon launch. Similar physics underlies the motion of each component of the ball- shown here in 240 fps slow motion. The Switch Pitch is produced by the makers of the Hoberman Sphere. 

Rattlesnake Eggs

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From Amazon: BUY NOW Buzzing Magnet Set 

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Rattlesnake Eggs: polished barium-strontium ferrite ceramic magnets influence each other when many centimeters apart, demonstrating the well known but mysterious action at distance via magnetic fields. Sometimes sold as “buzzers” these magnets come together with multiple bounces creating a characteristic zipper sound. Many shops and online vendors incorrectly label these as hematite- a completely different substance that does not magnetize well.

Newtons Yo-Yo

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From Educational Innovations: BUY NOW Newton's Yoyo 

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Newton Yo Yo: Newton's 3rd Law states that action force equals opposite reaction force- the the green and yellow spheres have equal mass, so the forces of the collision provide accelerations that are equal and opposite such that the spheres trade places.


Chain Fountain

The best effect (highest fountain) is obtained by using #10 size chain with a bead diameter of 3/16" (4.8mm). This spool has 100 feet of chain, the same length as used in the video. 
From Amazon: BUY NOW #10 ball chain 
Wikipedia has the details on the discovery of the chain fountain, and for those that want the physics here is the paper: Understanding the Chain Fountain from Proceedings of the Royal Society A, 2014 

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Chain Fountain: as the chain flows out of the glass under the pull of gravity the beads don't simply roll over the edge but instead arc up upward like a fountain. As each link is pulled and tilted upward the adjacent link is tilted downward and pressed into the pile- by Newton's 3rd law the pile presses back pushing each bead upward into the air. A segment of the video is shown in slow motion where the fountain is at maximum height. This phenomena was recently discovered by Steve Mould (more to be seen at his YouTube channel) and the details of the physics is described in the Proceedings of the Royal Society by Biggins & Warner (2014). 

Balance Pteranodon

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From Amazon: BUY NOW Balance Pteranodon 

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Balance Pteranodon: weights in the forward wing tips create a center of mass below this pterosaur's beak- making a system that can rotate and oscillate about a stable equilibrium condition. No magnets used or needed for this physics! Usually this toy is found in the form of a bird (direct dinosaur descendent). Pterosaurs are not dinosaurs, but are the largest animals to ever fly, and powered flight has only evolved four times: bats, birds, pterosaurs, and insects- in reverse order. 

MaBoRun Minis

Similar devices here:
From Amazon: BUY NOW MaBoRun Marble Run 

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MaBoRun Minis: rolling marbles doing tricks as gravitational potential energy is converted to kinetic energy. Three mini marble runs each with a battery powered means of lifting the marbles: 1) a belt driven gear, 2) a scissor linkage that translates the rotation of the motor into linear motion to lift the marbles to the top and 3) an Archimedean Screw conveyer. Two of these runs incorporate a simulation of decaying orbits with conservation of angular momentum as the marbles whirl down funnel shaped tracks.


Tornado Spheres

Just one of the amazing physics toys that will come in the next Curiosity Box, a great way to build you own collection! 

Get (or give!) a Curiosity Box subscription here: JOIN NOW: The Curiosity Box

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Tornado Spheres: two ball bearings welded together can be made to spin up to 2000+ rpm by the Magnus Effect using a stream of air. Shining three colored LEDs on the spinning pair produces an illusion of floating rings along with a second illusion that these rings are rotating and changing direction due to aliasing with the frame rate of the video camera (like the famous wagon-wheel effect).

Ring Catch Chain Trick

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From Amazon: BUY NOW Ring and Chain Set 

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The physics of this trick in great detail with more slow motion: Ring Falling into a Chain: No Magic — Just Physics 

Ring Catch Chain Trick: a solid ring will be caught by a loop of chain if it tumbles during its fall. By Newton's Third law, when the ring twists into and hits the chain, the impact transfers momentum to the end of the chain, which rises up and over the ring- seen here in 480 fps slow motion. 

Glass Hydro-Top

Available in four colors and designs: 
BUY NOW: Glass Water Tops

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Glass Hydro-Top: under centripetal acceleration a liquid will flow to create a cylindrical surface parallel to the axis of rotation. This blown glass dreidel contains a small amount of colored water that when spun resembles a blue gemstone banded around the rim. A unique design with fun physics!