{"title":"STEM Science Kits \u0026 Models","description":"\u003cp\u003eExplore science and engineering through hands-on STEM kits and working models. Discover mechanical gears, water-powered mechanisms, heat engines and geometry demonstrations for home learning, classroom activities and curious makers.\u003c\/p\u003e\u003cp\u003eSome products require assembly; others arrive as ready-to-use models. Check each product page for assembly details, materials and safety guidance.\u003c\/p\u003e","products":[{"product_id":"gravity-powered-pendulum-clock-kit-diy-mechanical-escapement-stem-model","title":"Gravity-Powered Pendulum Clock Kit – DIY Mechanical Escapement STEM Model","description":"\u003ch2\u003eA clock you can build and see inside\u003c\/h2\u003e\u003cp\u003eBuild a mechanical clock driven by a hanging weight, without batteries or a motor. The open frame lets learners watch the gear train, escapement and adjustable swinging regulator in action.\u003c\/p\u003e\u003ch3\u003eWhat learners discover\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGravitational potential energy and mechanical motion\u003c\/li\u003e\n\u003cli\u003eGear transmission and the role of an escapement\u003c\/li\u003e\n\u003cli\u003ePeriodic motion and calibration by moving the regulator weights\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eHow to use\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003eAssemble and securely hang the model. Attach a weight of approximately 550 g, such as a 550 ml water bottle (not included).\u003c\/li\u003e\n\u003cli\u003eTurn the winding key to raise the weight and gently start the regulator.\u003c\/li\u003e\n\u003cli\u003eCompare the motion with a stopwatch. Slide the regulator weights inward to speed it up or outward to slow it down.\u003c\/li\u003e\n\u003cli\u003eRewind when the hanging weight reaches the bottom.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eIn the box\u003c\/h3\u003e\u003cp\u003eFrame plates, gear wheels, dial, escapement and regulator with two adjustable weights, winding key, hour hand, hooks, drive cord and screwdriver.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eApproximate assembled size: 191 mm high × 135 mm wide × 95 mm deep\u003c\/li\u003e\n\u003cli\u003eMaterials: ABS plastic, metal hooks and hardware\u003c\/li\u003e\n\u003cli\u003eSuggested age: 8+, with adult guidance\u003c\/li\u003e\n\u003cli\u003ePower: gravity; hanging weight is not included\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eThis is a teaching model, not a precision timepiece. Accuracy depends on assembly, friction and adjustment. Do not exceed the recommended load. Keep fingers and hair clear of moving gears; contains small parts.\u003c\/p\u003e\n\u003ch3\u003eCalibration activity\u003c\/h3\u003e\u003cp\u003eModel reference: EK-D016. Compare several complete back-and-forth regulator swings with a stopwatch, then move both adjustable weights inward or outward and repeat. Aim for a rhythm near one second per complete swing; the model does not guarantee precise timekeeping. Observe how the escapement releases the gear train step by step and how rewinding restores the hanging weight’s potential energy.\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621197054035,"sku":null,"price":12.88,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/01.jpg?v=1791426200"},{"product_id":"jet-boat-experiment-kit-diy-water-jet-propulsion-buoyancy-stem-boat","title":"Jet Boat Experiment Kit – DIY Water-Jet Propulsion \u0026 Buoyancy STEM Boat","description":"\u003ch2\u003eBuild a boat powered by a backward water jet\u003c\/h2\u003e\u003cp\u003eAssemble a motor-driven jet boat and explore Newton’s third law, buoyancy, centrifugal pumping, rudder steering and simple circuits. The impeller sends water backward through the spray tube; the reaction force pushes the boat forward. The hollow hull provides buoyancy, and the pointed bow helps reduce water resistance.\u003c\/p\u003e\u003ch3\u003eAssembly and experiments\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003eConnect the motor, switch and battery contacts with the red and black wires, following the illustrated polarity markings.\u003c\/li\u003e\n\u003cli\u003eFit the motor in the hull, press the impeller onto the shaft and install the impeller cover and spray tube.\u003c\/li\u003e\n\u003cli\u003eInstall the contact plates, battery cover and pressure blocks. Secure the parts with the supplied screws.\u003c\/li\u003e\n\u003cli\u003eFit the steering wheel from above and the rudder from below. The steering is manual, not motor-driven; this is not a remote-control boat.\u003c\/li\u003e\n\u003cli\u003ePlace the boat in a shallow basin before switching on. Change the rudder angle and spray-tube direction to compare the boat’s path.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eIllustrated parts list\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eHull, rudder, battery cover, impeller, motor, steering wheel and impeller cover: 1 each\u003c\/li\u003e\n\u003cli\u003ePressure blocks: 2; decorative sticker: 1; screwdriver: 1\u003c\/li\u003e\n\u003cli\u003eRed wires: 2; black wire: 1; switch: 1; water spray tube: 1\u003c\/li\u003e\n\u003cli\u003eScrew A: 3; screw B: 2\u003c\/li\u003e\n\u003cli\u003eNegative spring contact, positive\/negative contact plate and positive spring contact: 1 each\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eBattery powered. Follow the battery type and polarity markings on the supplied compartment and instructions. Batteries are not shown in the illustrated parts list; do not assume they are supplied.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eApproximate assembled dimensions: 170 × 100 × 65 mm\u003c\/li\u003e\n\u003cli\u003eListed product weight: approximately 210 g, excluding shipping packaging\u003c\/li\u003e\n\u003cli\u003eConstruction: plastic hull with motor, metal contacts and wiring\u003c\/li\u003e\n\u003cli\u003eSuggested age: 8+, with adult guidance; assembly required\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eCare and safety\u003c\/h3\u003e\u003cp\u003eTest in a shallow sink, basin or tub, never in ponds, rivers or other open water. Put the boat in water before turning it on. Keep water out of the interior and fingers clear of moving parts. Switch off after use, remove the batteries for storage, and drain and dry the boat. Contains small parts; keep away from young children.\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621203148883,"sku":null,"price":10.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/01_f62ef7a9-1efe-444e-b83d-9249e36027cd.jpg?v=1791426514"},{"product_id":"pythagorean-theorem-model-a-b-c-water-sand-demonstration-kit","title":"Pythagorean Theorem Model – a² + b² = c² Water \u0026 Sand Demonstration Kit","description":"\u003ch2\u003eMake the Pythagorean theorem visible\u003c\/h2\u003e\u003cp\u003eExplore a² + b² = c² with a rotating model containing three transparent square chambers arranged around a right triangle. The chambers share the same depth, so their capacity is proportional to their square area.\u003c\/p\u003e\u003ch3\u003eHow the experiment works\u003c\/h3\u003e\u003cp\u003eFill the two smaller squares, close the plug, and rotate the disk in its stand. Watch the contents move into the larger square on the hypotenuse. Use the included experiment sand, or add clean water slowly with the dropper to reduce bubbles.\u003c\/p\u003e\u003cp\u003eThis is a visual demonstration of the area relationship, not a formal mathematical proof. Suitable for middle- and high-school geometry, classroom demonstrations, math clubs and family STEM activities.\u003c\/p\u003e\u003ch3\u003eIn the kit\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eTransparent three-square chamber, rotating base disk and support stand\u003c\/li\u003e\n\u003cli\u003eLarge and small O-rings and plug\u003c\/li\u003e\n\u003cli\u003e9 capped screws and screwdriver\u003c\/li\u003e\n\u003cli\u003eDropper and a bag of experiment sand\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications and care\u003c\/h3\u003e\u003cp\u003eApproximate size: 13.3 × 13.5 cm. Plastic construction with metal screws. Assembly required. Assemble with adult guidance and tighten screws evenly so the O-rings seal. Drain and dry after water experiments. Contains small parts; keep away from young children.\u003c\/p\u003e\u003ch2\u003e中文说明：勾股定理演示模型\u003c\/h2\u003e\u003cp\u003e三个透明方形腔体分布在直角三角形三边上，腔体深度相同，容量与面积成比例。向两个较小方格装入实验沙或清水，塞好后转动圆盘，观察内容物流入斜边上的大方格，直观演示a²+b²=c²的面积关系。\u003c\/p\u003e\u003cp\u003e配有透明腔体、旋转圆盘、支架、大\/小O形密封圈、塞子、9颗带帽螺丝、螺丝刀、滴管及实验沙。成品约13.3×13.5厘米，塑料及金属螺丝结构，需组装，适合初中以上几何学习及课堂演示。\u003c\/p\u003e\u003cp\u003e本模型是直观演示，不代替严格数学证明。成人指导组装并均匀拧紧螺丝，注水时减少气泡，使用后排水擦干。小零件远离幼儿。\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621206556755,"sku":null,"price":8.53,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/01_6b340bb9-4bea-4acf-8de8-3eb24570198f.jpg?v=1791426624"},{"product_id":"low-temperature-stirling-engine-model-runs-on-a-cup-of-hot-water","title":"Low-Temperature Stirling Engine Model – Runs on a Cup of Hot Water","description":"\u003ch2\u003eA desktop heat engine — no open flame required\u003c\/h2\u003e\u003cp\u003ePlace this low-temperature-difference Stirling engine on a cup of hot water, allow the base to warm, and give its iridescent flywheel a gentle turn. With a sufficient temperature difference between the warm base and cooler top, it converts heat into visible mechanical motion.\u003c\/p\u003e\u003ch3\u003eExplore thermodynamics\u003c\/h3\u003e\u003cp\u003eAir moves between warmer and cooler regions, expanding and contracting. Pressure changes drive the power piston and connecting rod, while the flywheel carries motion through the cycle. A hands-on demonstration of heat, temperature difference and mechanical work; not a practical electricity generator.\u003c\/p\u003e\u003ch3\u003eHow to use\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003eAn adult fills a suitable cup with hot water and sets it on a stable, level surface. The recommended cup opening is approximately 90 mm.\u003c\/li\u003e\n\u003cli\u003eCenter the engine securely on the cup. Allow about 20 seconds to warm, then gently start the flywheel.\u003c\/li\u003e\n\u003cli\u003ePerformance depends on water temperature, the temperature difference and setup. Let the model cool before storage.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eApproximate height: 160 mm\u003c\/li\u003e\n\u003cli\u003eBase diameter: 105 mm; flywheel diameter: 120 mm\u003c\/li\u003e\n\u003cli\u003eListed model weight: approximately 125 g, excluding shipping packaging\u003c\/li\u003e\n\u003cli\u003eAluminum alloy support, quartz heating cylinder and plastic flywheel\u003c\/li\u003e\n\u003cli\u003ePower cylinder: Ø12 mm, 10 mm stroke\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eHot water and warm metal can burn; adult handling and supervision are essential. Handle the flywheel and quartz cylinder gently, keep fingers clear of moving parts, and do not oil the mechanism. Cup and hot water are user-supplied.\u003c\/p\u003e\n\u003ch3\u003eDesign highlights\u003c\/h3\u003e\u003cp\u003eThe transparent iridescent flywheel makes rotation easy to observe. A low-friction shaft, silicone diaphragm and connecting rod support smooth movement. Powered by a hot-water temperature difference, with no batteries or open flame required.\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621208227923,"sku":null,"price":18.44,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/05.jpg?v=1791426676"},{"product_id":"gear-combination-kit-hand-cranked-gears-chain-belt-worm-drive-stem-model","title":"Gear Combination Kit – Hand-Cranked Gears, Chain, Belt \u0026 Worm Drive STEM Model","description":"\u003ch2\u003eFive transmission mechanisms on one base\u003c\/h2\u003e\n\u003cp\u003eBuild a hand-cranked model that brings spur gears, bevel gears, a chain drive, a belt drive and a worm drive together. Watch how different mechanisms transfer rotation and change shaft direction through a hands-on mechanical assembly.\u003c\/p\u003e\n\u003ch3\u003eExplore and learn\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eObserve the direction of adjacent externally meshing gears\u003c\/li\u003e\n\u003cli\u003eCompare the motion of different-sized gears, sprockets and pulleys under similar input conditions\u003c\/li\u003e\n\u003cli\u003eSee how bevel gears transfer rotation between differently oriented shafts\u003c\/li\u003e\n\u003cli\u003eCompare chain, belt and worm-drive arrangements\u003c\/li\u003e\n\u003cli\u003ePractise assembly, alignment and mechanical troubleshooting\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eIllustrated components\u003c\/h3\u003e\n\u003cp\u003eBase sections and joining parts, supports, long and short shafts, spur and bevel gears, sprockets and yellow chain links, pulleys with an O-ring belt, a worm, crank handle and sleeve. Exact quantities and supplied version should be checked against the packing list.\u003c\/p\u003e\n\u003ch3\u003eAssembly overview\u003c\/h3\u003e\n\u003cp\u003eJoin the base sections and mount the main supports and shafts. Fit the illustrated gears and sprockets, snap the chain links into a loop and fit the chain. Mount the bevel-gear shafts, pulleys and O-ring belt, then align the worm with its mating gear. Fit the crank and turn slowly to check all moving parts. Use the supplied assembly diagrams for hole positions and orientation.\u003c\/p\u003e\n\u003cp\u003eThis is a manually operated teaching model, not a powered machine or load-bearing device. Exact ratios, torque, dimensions, weight and load capacity have not been verified.\u003c\/p\u003e\n\u003ch3\u003eCare and safety\u003c\/h3\u003e\n\u003cp\u003eContains small parts; assemble with adult guidance and keep away from young children. Keep fingers, hair and clothing clear of gears, chain and belt. Stop and check alignment if it jams; do not force the crank, attach loads or add a powered drive.\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621212356691,"sku":null,"price":10.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/O1CN01asoIl81HQSo6To8RS__377280752.webp?v=1791426746"},{"product_id":"water-mill-experiment-kit-waterwheel-gears-cam-driven-pestle-stem-model","title":"Water Mill Experiment Kit – Waterwheel, Gears \u0026 Cam-Driven Pestle STEM Model","description":"\u003ch2\u003eBuild a tabletop waterwheel and mill\u003c\/h2\u003e\n\u003cp\u003eWatch flowing water turn a shaft, rotate a mill disc and move two pestle mechanisms up and down. A crank also permits a dry demonstration of the linked mechanical transmission.\u003c\/p\u003e\n\u003ch3\u003eHow it works\u003c\/h3\u003e\n\u003cp\u003eWater acting on the wheel blades rotates the wheel and shaft. Gears transfer rotation to the mill disc and change its axis. Cam-like shaft projections lift the pestle levers; when released, the pestles fall back down. The open construction makes water power, gear transmission, cams, levers and reciprocating motion visible.\u003c\/p\u003e\n\u003ch3\u003eIllustrated components\u003c\/h3\u003e\n\u003cp\u003eMill disc and base, waterwheel and retaining cover, 8-tooth gear, main base, two shaft supports, two type-A and two type-B pestle supports, crank, two pestles, shaft and cylindrical pin. This supplier table has 13 component categories, not 13 individual pieces; check actual contents against the supplied version.\u003c\/p\u003e\n\u003ch3\u003eAssembly and use\u003c\/h3\u003e\n\u003cp\u003eAssemble both pestle-lever units and mount them over the base recesses. Fit the shaft and supports, orient its projections to engage the levers, assemble and mount the waterwheel, then fit the gear, mill disc and crank. Check movement by turning slowly. Place the model in a tray before directing a small stream of water onto the blades. Water source and spill tray are user-supplied.\u003c\/p\u003e\n\u003ch3\u003eSupplier-stated specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eApproximate assembled size: 17.7 × 10.3 × 8.3 cm (not packaging dimensions)\u003c\/li\u003e\n\u003cli\u003eMain material: ABS plastic\u003c\/li\u003e\n\u003cli\u003eSuggested age: 8+, with adult guidance\u003c\/li\u003e\n\u003cli\u003eWater-driven or hand-cranked mechanical operation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis is an educational model, not a vehicle, food-processing appliance, pump or electrical generator. Contains small parts. Keep fingers clear of moving mechanisms; stop if it jams. Use water away from electrical equipment and sockets, control splashes, and drain and dry before storage. Do not ingest experiment water or components.\u003c\/p\u003e","brand":"RetroMakerKits by innoelement","offers":[{"title":"Default Title","offer_id":67621213929555,"sku":null,"price":9.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/0891\/1443\/files\/215dceef-3db9-4808-8d53-4d90ec0687aa.png?v=1791461585"}],"url":"https:\/\/www.retromakerkits.com\/collections\/stem-science-kits.oembed","provider":"RetroMakerKits by innoelement","version":"1.0","type":"link"}