{"title":"Mechanical Toys","description":"","products":[{"product_id":"acrylic-paint-set","title":"Acrylic Paint Set","description":"\u003cp\u003e\u003cspan\u003e12 acrylic colours and 3 paint brushes for decorating your Timberkits model! \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSadly the company that made these delightful wooden automata, Timberkits - a small family business based here in the UK, has now closed down. We have a few remaining Timberkits items, but once they have gone there will be no more. \u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49326434091355,"sku":"1131","price":9.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/acrylicpaints800x600.jpg?v=1729954140"},{"product_id":"chaos-pendulum-kit","title":"Chaos Pendulum Kit","description":"\u003cp\u003e\u003cspan\u003eA very elegant demonstration of chaotic motion...\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv class=\"ng-scope\"\u003eThis kit will enable you to build your own chaotic pendulum. In fact, you can build four different versions of the chaotic pendulum, depending on which pieces you decide to use! \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eMade of anodised aluminium, everything you need to construct the chaos pendulum is included in the box. \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eUnsuitable for small children due to small parts.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eSuggested age 14+\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eDesigned and manufactured in the UK\u003c\/div\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49344568492379,"sku":"1113","price":60.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/chaospendulum800x600.jpg?v=1730202454"},{"product_id":"hero-s-steam-turbine-kit","title":"Hero’s Steam Turbine Kit","description":"\u003cp\u003e\u003cspan\u003eThe original steam engine?\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv class=\"ng-scope\"\u003eHero's Steam Turbine is considered to be the first recorded steam engine or reaction steam turbine. The Greek-Egyptian mathematician and engineer Hero of Alexandria described the device in the 1st century AD, and many sources give him the credit for its invention. However, Vitruvius was the first to describe this appliance in his De architectura (ca. 30–20 BC).\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eIt is a simple, bladeless radial steam turbine which spins when the central water container is heated. Torque is produced by steam jets exiting the turbine.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eAlthough it demonstrated a principle, it is neither a practical source of power nor a direct predecessor of the type of steam engine invented during the Industrial Revolution.\u003cbr\u003e\u003cbr\u003eThis item is supplied in kit form. A hex or Allen key is supplied in the box. You will need to provide the fuel, which is methylated spirit or denatured alcohol if you are in the USA. \u003cbr\u003e\u003cbr\u003eTHIS IS NOT A TOY. ADULT USE ONLY. \u003c\/div\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49344761692507,"sku":"1112","price":90.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/herossteamturbine800x600.jpg?v=1730203552"},{"product_id":"snail-ball","title":"Snail Ball","description":"\u003cp\u003ePlace the golden metal ball at the top of the ramp and let it go. Does it roll down the ramp in the normal way? No, it rolls down extremely slowly. There doesn't seem to be anything unusual about the golden ball - it weighs about what you might expect. So what is happening? \u003c\/p\u003e\n\u003cp\u003eA clue - if you make the Snail Ball colder by popping it in the fridge for a while, it rolls down the ramp more slowly. And if you warm it up a bit, it will roll more quickly. \u003c\/p\u003e\n\u003cp\u003eInside the Snail Ball, which is hollow, there is a heavy ball bearing, which is smaller than the Snail Ball. There is also a viscous liquid. So the centre of gravity is lower than you might expect, and the heavy internal ball bearing prevents the Snail Ball just rolling quickly down the slope because of the viscous liquid. \u003c\/p\u003e\n\u003cp\u003eIf you don't know the secret it is very puzzling!\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49344802783579,"sku":"1104","price":60.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/snailball1800x600.jpg?v=1730203919"},{"product_id":"vortex-dome","title":"Vortex Dome","description":"\u003cp\u003e\u003cspan class=\"ng-scope\" graphik=\"\" font-size:=\"\" background-color:=\"\"\u003eThis is a beautiful physics toy designed for your desk. A vortex lives in here, just spin the gorgeous glass dome to see it!\u003c\/span\u003e\u003cbr class=\"ng-scope\" graphik=\"\" font-size:=\"\" background-color:=\"\"\u003e\u003cbr class=\"ng-scope\" graphik=\"\" font-size:=\"\" background-color:=\"\"\u003e\u003cspan class=\"ng-scope\" graphik=\"\" font-size:=\"\" background-color:=\"\"\u003e\u003cspan\u003eThe vortex is created by movements of the rheoscopic fluid inside the dome. There is a ball bearing underneath, which allows the dome to spin very easily. \u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eHandmade in the UK\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/span\u003e\u003cspan class=\"ng-scope\" graphik=\"\" font-size:=\"\"\u003e\u003cspan\u003eMaterials used:  Glass, stainless steel, rheoscopic fluid, ball bearing\u003c\/span\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345157890395,"sku":"918","price":85.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/vortexdome1800x600.jpg?v=1730209878"},{"product_id":"spendulum","title":"Spendulum","description":"\u003cdiv class=\"ng-scope\"\u003eThis is an example of complex behaviour from what appears to be a simple system - a mass attached to a spring. \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eA simple physics experiment involves making the mass oscillate up and down. However, under certain circumstances, when the mass used causes the rest length of the spring to extend by about one third, a curious thing happens. The vertical movement of the mass becomes unstable, and gradually the  up and down movement is replaced by a sideways motion, and the mass starts to behave like a pendulum, swinging from side to side, with no up and down motion at all. At least for a moment. Then the pendulum action starts to be replaced by the up and down movement again. The system will continue to switch between an up and down oscillation of the mass, and a sideways motion, where the mass behaves like a pendulum. \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eThere is a nonlinear coupling between the spring motion and the sideways pendulum motion which can become resonant for certain parameters of the system. This behaviour is known as autoparametric resonance.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\n\u003cdiv class=\"ng-scope\"\u003eCONTENTS\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e1. Extension Spring. 1mm W\/D, 25mm O\/D, 78mm Body Length, 125mm Overall Length. EN10270-1 Carbon Steel\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e2. 50 gram mass holder\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e3. Weights – 1 x 50g, 3 x 20g, 1 x 10g\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e4. Loop of nylon cord\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e5. 1976 article by M G Olsson, from Am. J. Phys. Vol. 44, No 12, December 1976\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e6. 2011 article by Chris Sangwin. See page 5 for the section about the spring\/pendulum effect.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e7. Instruction sheet\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345461485915,"sku":"971","price":39.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/spendulum800x600.jpg?v=1730211320"},{"product_id":"tims-nile-mug","title":"Tim's Nile Mug","description":"\u003cdiv class=\"ng-scope\"\u003eMade here in the UK, this elegant fine bone china mug showcases Tim, with quite a few references to the Nile! \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eTim made a video some years ago, where a vase mysteriously kept re-filling with water. See https:\/\/youtu.be\/KPKzGagdvNc  His phrase 'Water from the Nile' has passed into folklore on the Grand Illusions YouTube channel! \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eOur motion graphics designer David Chaudoir, the man who creates our titles, came up with such a lovely 'Water from the Nile' themed title sequence for our 2019 videos that we decided to create this mug as well, featuring the same design. It also shows Tim in his 'Suit of Arms'. \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eInside the rim of the mug, if you hold it in your right hand, you will see the words COFFEE FROM THE NILE. Hold it in your left hand, i.e. with the mug the other way around, and the words inside the mug read TEA FROM THE NILE. \u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eMade in Staffordshire, in the north of England, which has been a centre of ceramic production since the 18th century.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\n\u003cspan\u003eWARNING\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eWe are unable to supply this product to the state of California in the USA. We have received the following information from Dunoon, who are the UK manufacturers of this product.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003e\u003cem\u003eWe previously wrote to a number of our customers, mainly in the USA, regarding the sale of Dunoon products into California with respect to Proposition 65 (Prop 65). This is the Californian legislation specifically pertaining to the content of lead in products. Prop 65 requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm. By requiring that this information be provided, Prop 65 enables Californians to make informed decisions about their exposures to these chemicals.\u003c\/em\u003e\u003cbr\u003e\u003cbr\u003e\u003cem\u003eThe current situation in California is that unscrupulous Attorneys (often in these cases referred to as bounty hunters) are disregarding previous agreements between the Coalition of Safe Ceramics and the State of California, with respect to Prop 65 and are serving notices of proceedings on companies, even those whose products comply with the Prop 65 testing requirements, as our products do.\u003c\/em\u003e\u003cbr\u003e\u003cbr\u003e\u003cem\u003eThis is rarely contested by California’s Attorney General’s office and as such, defending companies served with these notices are forced to settle claims to avoid very costly court proceedings.\u003c\/em\u003e\u003cbr\u003e\u003cbr\u003e\u003cem\u003eGenerally, settlement claims vary but can be over $20,000 depending on the number of instances and length of time on display. \u003c\/em\u003e\u003c\/span\u003e\n\u003c\/div\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345542914395,"sku":"933","price":16.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/timsnilemug1800x600.jpg?v=1730212476"},{"product_id":"jumping-discs-set-of-3","title":"Jumping Discs - Set of 3","description":"\u003cp\u003e\u003cspan class=\"ng-scope\"\u003eThese little metal discs are bimetallic - they are made from two different metals - and this enables them to perform an amazing physics trick! The disc is slightly curved, and if you heat the disc in your hands you can then 'pop' the disk so that it bends the other way. You then place it on a flat surface, and it starts to cool. As it cools, the disc will, sooner or later, revert to the initial configuration. When this happens, the disc jumps several feet in the air! Make sure your hands are not too cold - one customer reported problems in getting the discs to work. However he then realised that he had just come in from helping his son make a snowman in the garden, and his hands were really cold. Once his hands warmed up, the discs worked again! One customer suggested holding the discs against a mug of hot tea, which certainly warms them up very effectively! These discs were originally supplied by Edmund Scientific in New Jersey some 15-20 years ago. When the man in charge of the operation sadly passed away, nobody knew how to produce the discs anymore. Now a new designer in Europe has started making them again.\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eHOW DO THEY WORK?\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eThe discs are in interesting example of differential expansion. The disc is a bimetal, having stainless steel on one side and invar on the other. Invar is a nickel-iron alloy containing 36% nickel. This alloy has a very low coefficient of linear expansion by comparison with the stainless steel. Heat causes the bimetal disc to expand and cooling makes it contract. Since the two surfaces expand and contract at highly different rates in response to changes in temperature, it is possible to 'lock' the disc in the loaded position when it is hot; then, as the disc cools, the increasing tension will eventually cause it to jump into the air as it reverts to its original shape!\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eThe discs are 25.4 mm in diameter. \u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eSupplied as a set of 3 discs. Made in EU\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345596326235,"sku":"219","price":11.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/jumpingdiscs800x600.jpg?v=1730212990"},{"product_id":"barrel-and-ball-puzzle-1","title":"Tesla Valve - Metal","description":"\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eNikola Tesla's valvular conduit is another one of his forgotten inventions. Invented in 1920 it has largely been overlooked. What is it? In simple terms it is a one-way valve. That in itself is not special. What makes it special is the fact it has NO moving parts. Think about that for a moment.\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eHow does a valvular conduit work? The design uses a particular shape. When the gas\/fluid flows in one direction it changes direction slightly, in a zigzag way but is relatively unrestricted and does not find much resistance. However, when it flows in the other direction because of the design the gas\/fluid gets spilt into two. These flows then end up meeting almost head on. This causes some resistance. This is repeated numerous times, each time reducing in pressure\/flow. This type of valve is never going to work as a seal for your wine bottle, it simply does not work that well at low pressures. However, when high pressures are used it comes into its own and the ratio between two directional flows gets higher and higher.\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eWhy did Tesla invent it? Tesla invented the valvular conduit around the time he was doing work with Tesla turbines. It seems to compliment his work with Tesla turbines rather than being a separate invention. Tesla turbines are primarily concerned with laminar flows (steady flows) and work better at higher pressures. Experiments I have conducted show that the Tesla valve on the other hand works best with pulsed flow. In fact it becomes highly effective with high pressure pulsed flows.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eWhen is most effective?\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003eAt high pressures. Experiments with an air compressor and higher pressures. Blowing into the valve will only produce a few psi at most and so leaks won't be an issue. Using compressed air at higher pressures (100psi or higher) you may find the odd leak. This probably won't be a huge issue for most experiments. The metal version can have the torx screws done up much tighter and hence only tiny leaks will be present, again this should be fine for 99% of applications. If you need a perfect seal a thin gasket could be cut to size to provide a better seal. Pressures up to 150psi have been tested for both plastic and metal versions. We don't recommend long term use at these pressures with the plastic version.\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003ePLEASE NOTE - this metal version of the Tesla Valve is made of machined aluminium. It comes with TWO top plates. One is made of clear plastic, so the inside of the valve is visible. The other is made of aluminium, which allows the valve to work at higher pressures. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003e-Nikola Tesla invention\u003cbr\u003e-One way valve (restricted flow) with no moving parts\u003cbr\u003e-Air and fluids pass freely one way but are slowed\/stopped the other way\u003cbr\u003e-You can blow in the holes and tell the difference\u003cbr\u003e-At higher pressures it become very effective\u003cbr\u003e-M6 female thread at each end (adapters can be sourced for most air systems)\u003cbr\u003e-Comes with 22 x T10 torx screws for maximum holding force\u003cbr\u003e-CNC machined aluminium base\u003cbr\u003e-M6 threaded connections\u003cbr\u003e-Adaptors are easily obtainable to other air connectors\u003cbr\u003e-T10 torx screwdriver required (fairly common)\u003cbr\u003e-18mm H x 225mm W x 22mm D\u003cbr\u003e-Based on US patent 1329559 dated 3rd Feb 1920\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345699479899,"sku":"727","price":49.99,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/teslavalve-metal1800x600.jpg?v=1730214211"},{"product_id":"tesla-valve-plastic","title":"Tesla Valve - Plastic","description":"\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eNikola Tesla's valvular conduit is another one of his forgotten inventions. Invented in 1920 it has largely been overlooked. What is it? In simple terms it is a one-way valve. That in itself is not special. What makes it special is the fact it has NO moving parts. Think about that for a moment.\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eHow does a valvular conduit work? The design uses a particular shape. When the gas\/fluid flows in one direction it changes direction slightly, in a zigzag way but is relatively unrestricted and does not find much resistance. However, when it flows in the other direction because of the design the gas\/fluid gets spilt into two. These flows then end up meeting almost head on. This causes some resistance. This is repeated numerous times, each time reducing in pressure\/flow. This type of valve is never going to work as a seal for your wine bottle, it simply does not work that well at low pressures. However, when high pressures are used it comes into its own and the ratio between two directional flows gets higher and higher.\u003c\/span\u003e\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003cspan class=\"ng-scope\"\u003eWhy did Tesla invent it? Tesla invented the valvular conduit around the time he was doing work with Tesla turbines. It seems to compliment his work with Tesla turbines rather than being a separate invention. Tesla turbines are primarily concerned with laminar flows (steady flows) and work better at higher pressures. Experiments I have conducted show that the Tesla valve on the other hand works best with pulsed flow. In fact it becomes highly effective with high pressure pulsed flows.\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eWhen is most effective?\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003eAt high pressures. Experiments with an air compressor and higher pressures. Blowing into the valve will only produce a few psi at most and so leaks won't be an issue. Using compressed air at higher pressures (100psi or higher) you may find the odd leak. This probably won't be a huge issue for most experiments. The metal version can have the torx screws done up much tighter and hence only tiny leaks will be present, again this should be fine for 99% of applications. If you need a perfect seal a thin gasket could be cut to size to provide a better seal. Pressures up to 150psi have been tested for both plastic and metal versions. We don't recommend long term use at these pressures with the plastic version.\u003cbr class=\"ng-scope\"\u003e\u003cbr class=\"ng-scope\"\u003e\u003c\/span\u003e\u003c\/span\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003ePLEASE NOTE - this version of the Tesla Valve is made of black machined plastic. It comes with a top plate made of clear plastic, so the inside of the valve is visible.\u003cbr\u003e\u003cbr\u003e-Nikola Tesla invention\u003cbr\u003e-One way valve (restricted flow) with no moving parts\u003cbr\u003e-Air and fluids pass freely one way but are slowed\/stopped the other way\u003cbr\u003e-You can blow in the holes and tell the difference\u003cbr\u003e-At higher pressures it become very effective\u003cbr\u003e-M6 female thread at each end (adapters can be sourced for most air systems)\u003cbr\u003e-Comes with 22 x T10 torx screws for maximum holding force\u003cbr\u003e-CNC machined plastic base\u003cbr\u003e-M6 threaded connections\u003cbr\u003e-Adaptors are easily obtainable to other air connectors\u003cbr\u003e-T10 torx screwdriver required (fairly common)\u003cbr\u003e-18mm H x 225mm W x 22mm D\u003cbr\u003e-Based on US patent 1329559 dated 3rd Feb 1920\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345893794139,"sku":"728","price":39.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/teslavalve-metal1800x600.jpg?v=1730214211"},{"product_id":"leidenfrost-ring","title":"Leidenfrost Ring","description":"\u003cdiv\u003eThe Leidenfrost Ring is an aluminium ring that demonstrates the Leidenfrost Effect. The Leidenfrost Effect occurs when a liquid comes into contact with a hot object, with the correct temperature difference between the two. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eFor example, if you heat a frying pan to a temperature over 100 degrees Centigrade, but less than 160 degrees Centigrade, and then place a drop of water in the pan, the drop of water will boil and spit and turn to steam very quickly; at 160 degrees Centigrade, it is really quick! \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eHowever if you heat the frying pan to a temperature of 200 degrees Centigrade or more, you will then see the Leidenfrost Effect - place a drop of water in the frying pan and you will see that the drop of water floats around in the pan, hovering on a tiny cushion of steam, which is about 0.1mm thick. This cushion of steam effectively insulates the drop of water from the frying pan, and the drop will hover around in the pan for a surprisingly long time. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eOur Leidenfrost Ring is made from solid aluminium, and has a pattern of ridges on the surface which cause the drop of water to move around the ring. The side walls retain the water drop inside the ring. You can experiment with slightly different temperatures and sizes of drop. It is even possible to have a loop of water spinning around in the ring. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eFor our demonstration, we placed the Leidenfrost Ring on a piece of mild steel, which provided some thermal mass, and placed the steel on an old baking tray, on top of a small gas powered cooker. The mild steel was painted with heatproof black paint, since the infrared thermometer we were using does not work on shiny surfaces like aluminium. It should also be possible to reach 200 degrees Centigrade in a domestic oven. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe Leidenfrost Ring is 42 mm in diameter. You will need to provide all the other equipment. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cdiv\u003eTHIS IS NOT A TOY!\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eTo stop the build up of limescale, it is best to use distilled water. There is a risk of burns from boiling water, steam and also the hot apparatus. You should use safety goggles when using this product. And also, if you place the Leidenfrost Ring inside a saucepan or a frying pan in order to heat it, make sure that the pan can take the heat. \u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThere is an article about the Leidenfrost Effect here - www.bath.ac.uk\/research\/news\/2015\/05\/19\/leidenfrost-thermostat\/\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe Leidenfrost Effect is named after Johann Gottlieb Leidenfrost, who discussed this effect in a paper he published in 1756.\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49345923547483,"sku":"796","price":35.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/leidenfrostring1800x600.jpg?v=1730217291"},{"product_id":"low-temperature-stirling-engine","title":"Low Temperature Stirling Engine","description":"\u003cp\u003e\u003cspan\u003eOne spin of the flywheel and this Low Temperature Stirling Engine shows a clean and simple way of converting thermal energy into motion. This engine will operate from many heat sources, including hot water, computer monitor, TV and the human hand. As long as there is a small difference (about 10 degrees) in temperature between the upper and lower plates this engine will run. The ready assembled engine is supplied in a rigid black card tube, approximately 160mm diameter and 200mm tall. This Low Temperature Stirling Engine has black anodised aluminium top and bottom plates. Aluminium has excellent thermal properties, and conducts heat very efficiently.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eEngine features:-\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Low profile heat insulated chamber pillars, giving a flat bottom and good surface contact with heat source\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Both connecting rods are positively located using low friction PEEK and stainless steel screws\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- All airtight seals are made with high strength precision screw threads and nitrile O rings\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Ultra low friction demagnetised and de-greased bearings, NO lubrication required\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Fully CNC machined, giving crisp, clean and tidy edges all over\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Engine parts ultrasonically cleaned before hand assembly\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eEngine materials:-\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Stainless steel connecting rods and ball-race bearings\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Micron precision Borosilicate glass cylinder\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Micron precision Graphite power piston\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Aluminium main pillar, hub and spokes\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Brass chamber pillars and flywheel rim\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Brass gland and cylinder holder\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eEngine dimensions:-\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Base plates - 92mm diameter, 2mm thick\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Displacer - 70mm diameter, 8mm thick\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Flywheel - 82mm diameter, 4mm thick\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Power piston - 9.5mm diameter\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e- Overall height - 120mm\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eMade in the UK\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49611140497755,"sku":"612","price":115.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/lowtemperaturestirlingengine1.jpg?v=1733149815"},{"product_id":"wimshurst-machine-kit","title":"Wimshurst Machine Kit","description":"\u003cp\u003e\u003cspan\u003eThis high quality cardboard construction kit allows you to build your own version of the classical high voltage generator - with limited current for safe experiments! For many people this machine is the most vivid memory of their physics classes at school. Everybody is fascinated by the crackling flashes of lightning that appear between the electrodes when the crank on the back is turned. Two counter-rotating acrylic discs with aluminium segments produce static electricity of up to 70,000 volts that is stored in two Leyden jars made from PVC and aluminium foil. The Leyden jars are discharged via two spherical electrodes, producing bright sparks. The capacity of the Leyden jars is deliberately limited, so that the electricity produced is completely harmless.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eThe finished kit is 29cm high\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":49611776360795,"sku":"663","price":55.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/wimshurstmachine.jpg?v=1733154493"},{"product_id":"wilberforce-pendulum","title":"Wilberforce Pendulum","description":"\u003cp\u003e\u003cspan\u003eDiscovered by the physicist Lionel Robert Wilberforce around 1896, the Wilberforce Pendulum is an example of a coupled mechanical oscillator. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWhen properly calibrated, the pendulum weight will initially move up and down, but the motion will then change until the weight is rotating, and there is no up and down motion at all. Then gradually the motion changes back to the up and down motion, and so on. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe up and down motion causes the spring to wind and unwind slightly, giving the mass a small rotation. \u003c\/span\u003e\u003cspan\u003eEach oscillation causes the mass to rotate a little more, until the mass is undergoing purely rotational motion and no longer bobbing up and down. Thus the translational up and down energy slowly transfers to rotational energy. Likewise, when the mass is rotating back and forth, the spring winds and unwinds. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWhen it unwinds, the tension in the spring decreases and the mass drops as there is a smaller upward force pulling it up. Thus for each rotation it undergoes, the rotational energy starts to transfer back to translational energy, and the weight bobs up and down with greater amplitude, until it eventually transfers entirely back, and undergoes purely up and down motion. At this point the process repeats.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eKit Contains: (1) Adjustable Wilberforce Pendulum Mass, (1) Helical Spring, (1) Mounting Rod connected to a boss head clamp.  \u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":51401555673435,"sku":"972","price":49.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/wilberforcependulum800x600_426232c3-4902-4bca-8ce0-e6dfec624c10.jpg?v=1758796492"},{"product_id":"knee-knock-doc-kit","title":"Knee Knock Doc Kit","description":"\u003cdiv class=\"ng-scope\"\u003e\n\u003cp\u003eTesting those reflexes and getting a dramatic reaction!\u003c\/p\u003e\n\u003cp\u003eDoctor can be male or female.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eAdd paint to really bring your model to life.\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eFinished model dimensions:\u003cbr\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eWidth: 150mm\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eHeight: 250mm\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003eDepth: 150mm\u003c\/div\u003e\n\u003cdiv class=\"ng-scope\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eSkill Level - Advanced\u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cspan class=\"ng-scope\"\u003eSadly the company that made these delightful wooden automata, Timberkits - a small family business based here in the UK, has now closed down. We have a few remaining Timberkits items, but once they have gone there will be no more. \u003c\/span\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":51468864127323,"sku":"1150","price":55.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/kneeknockdoc800x600_e7e4568f-61b6-41b2-9710-cc9fb4d7b2fd.jpg?v=1759766512"},{"product_id":"vintage-car-kit","title":"Vintage Car Kit","description":"\u003cp\u003eGetting ready for the rally. Parp! Parp! The open road!\u003c\/p\u003e\n\u003cp\u003eAdd paint to your model to really bring it to life.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinished model dimensions:\u003c\/strong\u003e\u003cbr\u003e\u003cspan\u003eWidth: 210mm\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eHeight: 245mm\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eDepth: 170mm\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSkill level - Advanced\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSadly the company that made these delightful wooden automata, Timberkits - a small family business based here in the UK, has now closed down. We have a few remaining Timberkits items, but once they have gone there will be no more. \u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":51472785801563,"sku":"1152","price":55.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/vintagecarkit1800x600_2e253bc0-dc91-4c3c-ae21-0c59946a327e.jpg?v=1759835796"},{"product_id":"the-moon-clock","title":"The Moon Clock","description":"\u003cp\u003eThis Clock Shows the Phases of the Moon!\u003cbr\u003e\u003cbr\u003eLike the Moon, this astronomical clock moves very slowly. It takes 29 days, 12 hours and 44 minutes for the moon sphere to show all its phases, which is exactly the average time from one New Moon to the next.\u003c\/p\u003e\n\u003cp\u003eHow is that possible?\u003cbr\u003e\u003cbr\u003eInside the Moon Clock, a half-white, half-black sphere turns very slowly, driven by a special battery powered mechanism so that it continuously displays the current phase of the Moon. It does this minute to minute, from the first delicate Crescent Moon, to the waxing Half Moon, to the Full Moon, and then back to the New Moon. The representation of the phases is as accurate as the Moon itself, because the always half illuminated Moon behaves the same way in its interaction with the Sun.\u003c\/p\u003e\n\u003cp\u003eAssembling this cardboard kit is straightforward and quickly produces a very elegant result.\u003c\/p\u003e\n\u003cp\u003eThis kit contains:\u003c\/p\u003e\n\u003cp\u003e3 pre-cut and printed A4 sheets of construction cardboard\u003cbr\u003e1 printed A4 sheet of construction cardboard for cutting out\u003cbr\u003e1 special clock movement, 56 x 56 x 16 mm, rotation in 29.53 days, incl. washer (metal), rubber washer and nut (metal)\u003cbr\u003e2 EVA hemispheres, Ø 40 mm x 20 mm, 1 black and 1 white (moon hemispheres)\u003cbr\u003e3 wooden toothpicks, Ø 2 mm x 80 mm (extension of the moon shaft)\u003cbr\u003e1 cardboard drinking straw, Ø 6 mm x 140 mm (reducing sleeve)\u003c\/p\u003e\n\u003cp\u003eDetailed assembly instructions\u003c\/p\u003e\n\u003cp\u003eNot included: 1 AA battery\u003c\/p\u003e\n\u003cp\u003eFeatures: 1 rotation in 29 days, 12 hours and 44 minutes\u003c\/p\u003e\n\u003cp\u003eDimensions of the built item: approx. 12 x 7.5 x 14.5 cm\u003c\/p\u003e\n\u003cp\u003eConstruction time: approx. 4 hours\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":51965889577307,"sku":"1163","price":22.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/the-moon-clock800x600.jpg?v=1767022765"},{"product_id":"gallus-light","title":"Gallus Light","description":"\u003cp\u003eThe Gallus Light consists of a dark mahogany wooden base, a brass candle housing and a glass chimney. It contains a tea light candle. Overall, it is a very elegant candle holder. However the most amazing and beautiful feature is that when the candle is lit, the flame slowly rotates at the rhythm of a human heart beat! The glass chimney prevents the flame from blowing out. \u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eWooden base made of mahogany \u003c\/li\u003e\n\u003cli\u003eCleaning Brush\u003c\/li\u003e\n\u003cli\u003eBrass housing\u003c\/li\u003e\n\u003cli\u003eStainless steel lining\u003c\/li\u003e\n\u003cli\u003eBoron silicate (heat resistant) glass chimney\u003c\/li\u003e\n\u003cli\u003e4 high quality tea-light candles\u003c\/li\u003e\n\u003cli\u003eDetailed instructions in six languages\u003c\/li\u003e\n\u003cli\u003eElegant presentation box\u003c\/li\u003e\n\u003cli\u003eMade in Switzerland\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003ePS Some of the pictures show the Gallus Light with a lighter coloured wooden base. However the Gallus Lights we sell all have the darker, mahogany base. \u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":52828737798491,"sku":"1169","price":110.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/galluslight1800x600.jpg?v=1776437263"},{"product_id":"replacement-glass-chimney-for-gallus-light","title":"Replacement Glass Chimney for Gallus Light","description":"\u003cp\u003eA replacement glass chimney for the Gallus Light.\u003c\/p\u003e\n\u003cp\u003eIt is held in place by three metal clips and you can easily slide a new chimney in place without needing any tools. \u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":52878497710427,"sku":"1170","price":11.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/replacementchimney800x600.jpg?v=1777276758"},{"product_id":"pythagoras-mug","title":"Pythagoras Mug (Or Greedy Cup!)","description":"\u003cp\u003eThese little pottery mugs are sold in Greece, especially on the island of Samos, and they are based on a design that is supposedly about 2,500 years old. A simple piece of physics, although slightly deeper in philosophical terms.\u003c\/p\u003e\n\u003cp\u003eThe mug looks normal, except that there is a central column inside the mug. If you pour water or wine into the mug, you can then drink it in the normal way. However, you must be careful when filling the mug. If you do not put too much liquid in, everything will be fine.\u003c\/p\u003e\n\u003cp\u003eHowever, if you fill the mug beyond a certain point, indicated by the line on the inside, the mug will empty by itself - every drop will drain out from a hole in the bottom, and you won't get a drink at all. The mug incorporates an internal siphon, and it is attributed to the Greek philosopher Pythagoras, who lived on the Island of Samos 2,500 years ago.\u003c\/p\u003e\n\u003cp\u003eAs he wrote nothing himself, we only know about Pythagoras from the writings of other people, especially Plato. However, as well as his fame as a mathematician, he is also celebrated for his philosophy and his way of life. The Pythagoras mug illustrates a point that we should not ask for more than our share in life - if we are too greedy, we might end up with nothing at all!\u003c\/p\u003e\n\u003cp\u003eCeramic item, handmade in Greece\u003cbr\u003eHeight: 105 mm, Diameter: 95 mm\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":52895772934491,"sku":"664","price":19.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/pythagorasmug1800x600.jpg?v=1777492549"},{"product_id":"storm-glass","title":"Storm Glass","description":"\u003cp\u003eThe Storm Glass was, as far as we know, first used in about 1750 by sailing ships to predict stormy weather.\u003cbr\u003e\u003cbr\u003eThe first proper report concerning its use on board a ship stems from the Darwin Expedition in 1831-1836. On December 27th 1831, Charles Darwin set off in the three-masted bark “HMS Beagle” under the command of Captain Robert Fitzroy (1805-1865), who throughout his career at sea and on land used the Storm Glass as a way of predicting the weather. Fitzroy was also a meteorologist who later became director of the British Meteorological Office. He wrote the famous “Weather Book” popularising the art of forecasting the weather. \u003c\/p\u003e\n\u003cp\u003eFitzroy believed that the Storm Glass worked because of  static electricity in the fields around us. A somewhat revolutionary thought at the time! He claimed that \u003cem\u003e\"if fixed, undisturbed, in free air, not exposed to radiation, fire, or sun, but in the ordinary light of a well-ventilated room or outer air, the chemical mixture in a so-called storm-glass varies in character with the direction of the wind, not its force, specially (though it may so vary in appearance only) from another cause, electrical tension\".\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003eIn 1859, violent storms struck the British Isles. In response, the British Crown distributed storm glasses, then known as \"FitzRoy's storm barometers\", to many small fishing communities around the British Isles for consultation by ships in port before setting sail.\u003cbr\u003e\u003cbr\u003eThe Storm Glass is thought of as a form of barometer. You can consult it daily to see what the weather is going to do in the next 24 hours or so. Others apparently use the Storm Glass to predict when the fish are biting! The mechanism by which it works is still debated. While a barometer measures the atmospheric pressure, an article in the 2008 Journal of Crystal Growth concluded that temperature change is the sole cause of crystal growth in storm glasses.\u003c\/p\u003e\n\u003cp\u003eFor optimum use, place the Storm Glass in a cool place, for example in a north-facing window or on a boat. Once it has settled down, the pattern of crystals inside the storm glass is supposedly an accurate indication of the weather over the next day or so. A historical curiosity and certainly a fascinating talking piece. See the illustrations for the different crystal patterns. \u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eMade with polished brass, the bracket to hang it up is included.  \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eHeight 145mm\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eWeight 450g\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":53005143703899,"sku":"282","price":100.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/stormglass1800x600.jpg?v=1779119604"},{"product_id":"the-dancing-disc","title":"The Dancing Disc Kit","description":"\u003cp\u003e\u003cspan\u003eThis fascinating physics demonstration mesmerises everyone that sees it. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe base is a slightly concave mirror. There is then a heavy metal disc, which you place on the mirror, and spin. What happens then? Well, just like spinning a coin on a table, the disc both spins and rolls, until it comes to a sudden stop, the final stages being accompanied by a sound of increasing frequency. A coin spun on a table will not spin for very long. The Dancing Disc, by contrast, spins for a long time before coming to rest. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe steel disc weighs 450 grams, and can easily be made to spin for a minute and a half or even longer! The best thing really is to watch the video. It is a lot of fun showing this to someone who has not seen it before - the fact that it spins for so long is surprising, as is the ending. The ending is not only spectacular, it also has a spectacular name - a finite-time singularity!\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eThe kit requires some construction in order to complete the base. \u003c\/p\u003e\n\u003cp\u003eThe kit includes: cardboard parts for the mirror bezel, 2 brass foil stickers for the disk\u003c\/p\u003e\n\u003cp\u003eDisc diameter: 7.5 cm\u003cbr\u003eDisc thickness: 1.3 cm\u003cbr\u003eDisc weight: 433 g\u003cbr\u003eMirror diameter: 20 cm\u003c\/p\u003e\n\u003cp\u003eThe mirror is made of glass, and therefore we recommend that it is suitable for Age 14+. It is suitable for younger children under supervision. This is not a toy. \u003c\/p\u003e\n\u003cp\u003eFor customers in North America, we suggest you buy this item instead - https:\/\/www.toysmith.com\/products\/eulers-disk\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":53020005073243,"sku":"1176","price":39.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/the-dancing-disc1800x600.jpg?v=1779185604"},{"product_id":"solar-projector","title":"Solar Projector Kit","description":"\u003cp\u003e\u003cspan\u003eThis practical instrument projects the Sun onto a viewing screen. The diameter of the projection is adjustable to 55 or 75mm. Easy and secure to use and therefore \u003c\/span\u003eideal to introduce children to the Sun, especially since more than one person can view the projected image at the same time.\u003cspan\u003e The optics consists of an achromatic glass lens, one plane and two convex mirrors. The projector can be adjusted from 0 to 90 degrees on its Dobsonian mount, and two quadrants measure the Sun’s declination. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eThis device allows you to see sunspots and also is a great way to observe solar eclipses. \u003c\/p\u003e\n\u003cp\u003eContents of the kit\u003c\/p\u003e\n\u003cp\u003e✴ 8 pre-punched sheets of cardboard\u003cbr\u003e✴ 1 achromatic glass lens OPTI Media 569.OAL, 30 mm diameter, f = 250 mm\u003cbr\u003e✴ 2 convex mirrors 16.5 mm diameter, f = -10.2 and -14.0 respectively\u003cbr\u003e✴ 1 acrylic glass plane mirror 54 x 90 mm \u003cbr\u003e✴ Instructions\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eYou will need to supply\u003c\/p\u003e\n\u003cp\u003e✴ Standard solvent based all purpose glue, e.g. UHU, Evo-Stik Impact, B\u0026amp;Q All Purpose Glue. Do not use water-based glue: it softens and warps the cardboard, and doesn't stick properly to the printed surfaces. Solvent based\u003cbr\u003eglues also dry much faster.\u003cbr\u003e✴ Double sided sticky tape for the plane mirror. Some solvent based glues can\u003cbr\u003edamage its reflective coating.\u003cbr\u003e✴ An elastic band for mounting the glass lens.\u003cbr\u003e✴ Two pieces of thin thread and two glass or metal beads for the quadrants.\u003cbr\u003e✴ A sharp knife with a fine point (thin carpet knife, craft knife, scalpel), to cut the thin holding tabs of the pre-punched parts.\u003cbr\u003e✴ A cutting board or mat, made from hardboard, plastic, or wood. Self healing cutting mats are ideal as the material re-closes after each cut.\u003cbr\u003e✴ For perfectionists: a black felt tip pen to blacken the white edges of the inner apertures, lens holder, etc. before construction.\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSize: 20 x 20 x 25 cm\u003c\/span\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":53141592637787,"sku":"1178","price":27.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/solarprojector1800x600.jpg?v=1779973895"},{"product_id":"nocturnal","title":"Nocturnal","description":"\u003cp\u003eThe Universal Pocket Nocturnal is a star clock used to determine the time at night using fixed stars visible in both the Northern and Southern Hemispheres - Polaris in the Northern Hemisphere and Alpha \u0026amp; Beta Centauri plus the Southern Cross in the Southern Hemisphere.\u003c\/p\u003e\n\u003cp\u003eThe Nocturnal was invented over 500 years ago to determine the time at night using bright stars. The original instrument worked in the Northern Hemisphere using the pole star Polaris for reference and Kochab for the hour angle. However, the original design could not be used in the Southern Hemisphere as there was no corresponding bright star at the South Celestial Pole. In 2023, Tony Sprent in Tasmania developed a new design using Alpha and Beta Centauri and the Southern Cross for use in the Southern Hemisphere.\u003c\/p\u003e\n\u003cp\u003eProduced in a small workshop in Spain, this carefully crafted instrument measures just 60 mm (approximately 2 inches) in diameter and meets international sizing standards for pocket watches. Made of solid brass, the Kala Universal Pocket Nocturnal is a contemporary take on historical models.\u003c\/p\u003e\n\u003cp\u003eThis charming instrument will remain operationally accurate for many years because the variation in the direct ascension varies very little over the course of centuries, making it a truly long-lived instrument and unique gift.\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":54092025168219,"sku":"1182","price":69.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/nocturnal1800x600.jpg?v=1789572029"},{"product_id":"chaotic-magnet-spinner-kit","title":"Chaotic Magnet Spinner Kit","description":"\u003cp\u003eA beautifully engineered magnetic curiosity that produces mesmerising, unpredictable motion...\u003c\/p\u003e\n\u003cp\u003eThe Chaotic Magnet Spinner is a precision‑machined desktop demonstrator that showcases the strange and fascinating behaviour of coupled magnetic systems. Two three‑spoke rotors sit opposite each other, each fitted with magnet spokes arranged in a deliberate polarity pattern — NSN on one rotor and SNS on the other. When you spin one rotor, the second begins to move seemingly of its own accord, pulled and pushed by the shifting magnetic fields.\u003c\/p\u003e\n\u003cp\u003eThe result is true chaotic rotation: sometimes synchronised, sometimes repelled, sometimes transferring momentum abruptly from one wheel to the other. No two runs are ever the same.\u003c\/p\u003e\n\u003cp\u003eEach rotor carries three embedded magnets arranged in a polarity pattern that ensures the wheels interact in a constantly changing magnetic landscape. As one wheel spins, the opposing poles alternately attract and repel, creating a dynamic torque exchange.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThis interaction produces-\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eChaotic motion\u003c\/strong\u003e — irregular, non‑repeating rotation patterns\u003cbr\u003e\u003cstrong\u003eSudden energy transfer\u003c\/strong\u003e — one wheel can stop dead while the other accelerates\u003cbr\u003e\u003cstrong\u003eMagnetic coupling without contact\u003c\/strong\u003e — motion driven entirely by field interaction\u003cbr\u003e\u003cstrong\u003eLong spin times\u003c\/strong\u003e — low‑friction bearings and balanced spokes\u003c\/p\u003e\n\u003cp\u003eThe behaviour is governed by real physics — but feels almost magical!\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eEngineering \u0026amp; Materials\u003c\/strong\u003e\u003cbr\u003ePrecision‑machined aluminium hubs and spokes\u003cbr\u003eHigh‑strength neodymium magnets\u003cbr\u003eLow‑friction de-oiled and demagnetised bearings for smooth, long‑lasting rotation\u003cbr\u003eRigid base and support structure for stable operation\u003cbr\u003eDesigned and engineered in England\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat makes it special\u003c\/strong\u003e\u003cbr\u003eA perfect desk curiosity for engineers, physicists, and lovers of mechanical oddities\u003cbr\u003eDemonstrates chaotic systems, magnetic coupling, and energy transfer\u003cbr\u003eHypnotic to watch — every spin behaves differently\u003cbr\u003eBuilt with the same attention to detail and quality expected of British precision workshop pieces\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIdeal for\u003c\/strong\u003e\u003cbr\u003eSTEM education\u003cbr\u003eEngineering enthusiasts\u003cbr\u003eCollectors of scientific curiosities\u003cbr\u003eAnyone who enjoys beautifully made kinetic desk art\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003cbr\u003eBase- 100mm diameter, 8mm thick (3.93\" x 0.31\")\u003cbr\u003eOverall height - 130mm (5.1\")\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eKit\u003c\/strong\u003e\u003cbr\u003eThe Spinner is supplied as a self-assembly kit. Assembly should take between 10-15 minutes and clear downloadable instructions are provided.\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e","brand":"Grand Illusions","offers":[{"title":"Default Title","offer_id":54135844438363,"sku":"1183","price":49.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0881\/4018\/5947\/files\/chaosmagnetspinnerkit800x600.jpg?v=1790002686"}],"url":"https:\/\/www.grand-illusions.com\/collections\/mechanical-toys.oembed?page=3","provider":"Grand Illusions","version":"1.0","type":"link"}