{"product_id":"centripetal-force-experiment-demonstrator-wooden-metal-roller-model-for-science-education-and-classroom-teaching-k1kf","title":"Demonstration looping track, single or double loop - CENTRA","description":"\u003cstyle\u003e\n.aa{font-family:Georgia,'Times New Roman',serif;color:#1A1A1A;line-height:1.7;font-size:15px;max-width:760px;margin:0 auto}\n.aa p{margin:0 0 1rem}\n.aa a{color:#185FA5;text-decoration:underline}\n.aa .aa-title{display:inline-block;border-bottom:2px solid #FAC775;padding-bottom:4px;font-size:16px;font-weight:600;margin:1.75rem 0 .5rem;letter-spacing:.3px;color:#1A1A1A}\n.aa .aa-badge{display:inline-block;font-size:11px;font-weight:700;letter-spacing:.5px;text-transform:uppercase;padding:3px 10px;border-radius:20px;margin:0 4px 4px 0;vertical-align:middle;font-family:Georgia,serif}\n.aa .aa-badge-or{background:#FAC775;color:#1A1A1A}\n.aa .aa-badge-brun{background:#5C3A1E;color:#FFF9E8}\n.aa .aa-badge-noir{background:#1A1A1A;color:#FAC775}\n.aa 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summary::after{content:\"\\2212\"}\n.aa .aa-a{font-size:13px;color:#3a3a3a;margin-top:.5rem}\n.aa .aa-a p{margin:0 0 .5rem}\n@media(max-width:600px){.aa .aa-vars,.aa .aa-ben{grid-template-columns:1fr}}\n\u003c\/style\u003e\n\u003cdiv class=\"aa\"\u003e\n\n\u003cp\u003e\u003cspan class=\"aa-badge aa-badge-noir\"\u003eThe Lab\u003c\/span\u003e \u003cspan class=\"aa-badge aa-badge-bleu\"\u003eEducational Equipment\u003c\/span\u003e How high must the marble be raised to complete the loop? This \u003cstrong\u003edemonstration loop track\u003c\/strong\u003e turns the question into an experimental protocol. Its \u003cstrong\u003eV-profile aluminum rails\u003c\/strong\u003e launch from a long \u003cstrong\u003estarting ramp\u003c\/strong\u003e, trace one or two vertical loops, and then end in a \u003cstrong\u003ecatching net\u003c\/strong\u003e that collects the marble at the finish. The whole assembly is mounted on a \u003cstrong\u003ewooden base\u003c\/strong\u003e approximately 40 cm long. Two versions are available: the \u003cstrong\u003esingle loop\u003c\/strong\u003e for a direct demonstration, or the \u003cstrong\u003edouble loop\u003c\/strong\u003e, which combines a large circle of approximately 7 cm in radius with a small one of approximately 3.5 cm to compare passage thresholds. According to the manual, the demonstrator comes with a \u003cstrong\u003esteel marble\u003c\/strong\u003e and a \u003cstrong\u003eplastic marble\u003c\/strong\u003e 2.5 cm in diameter: perfect for testing the influence of mass and observing that it changes almost nothing. Conservation of energy, minimum speed at the summit, friction: every launch becomes a measurement, every failure a hypothesis to be reformulated.\u003c\/p\u003e\n\n\u003ch3 class=\"aa-title\"\u003eAvailable versions\u003c\/h3\u003e\n\n\u003cdiv class=\"aa-vars\"\u003e\n\n\u003cdiv class=\"aa-var\"\u003e\n\n\u003cdiv class=\"aa-var-v light\" style=\"background: #9A9A9A;\"\u003eSINGLE LOOP\u003c\/div\u003e\n\n\u003cdiv class=\"aa-var-i\"\u003e\n\n\u003cspan class=\"aa-var-n\"\u003eSingle loop\u003c\/span\u003e\u003cspan class=\"aa-var-d\"\u003eOne vertical loop: the most direct demonstration\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-var\"\u003e\n\n\u003cdiv class=\"aa-var-v dark\" style=\"background: #1A1A1A;\"\u003eDOUBLE LOOP\u003c\/div\u003e\n\n\u003cdiv class=\"aa-var-i\"\u003e\n\n\u003cspan class=\"aa-var-n\"\u003eDouble loop\u003c\/span\u003e\u003cspan class=\"aa-var-d\"\u003eLarge circle (≈ 7 cm radius) and small circle (≈ 3.5 cm) for comparison\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-mat\"\u003e\n\n\u003ch3\u003eEnergy, height, and critical velocity\u003c\/h3\u003e\n\n\u003cp\u003eReleased at the top of the ramp, the marble possesses \u003cstrong\u003egravitational potential energy\u003c\/strong\u003e proportional to its height. As it descends, this reserve is converted into \u003cstrong\u003ekinetic energy\u003c\/strong\u003e. Part of this energy is then reinvested to regain altitude in the loop. The balance, established by 19th-century physicists under the name of \u003cstrong\u003econservation of mechanical energy\u003c\/strong\u003e, allows for the prediction of the marble's speed at every point of the journey, friction notwithstanding.\u003c\/p\u003e\n\n\u003cp\u003eAt the top of the circle, the only question is whether the marble is moving fast enough for the curved trajectory to be sustainable: v² ≥ g·R is required. Coupled with the energy balance, this condition provides a minimum starting height of \u003cstrong\u003e2.5 times the radius\u003c\/strong\u003e for an object that slides, and approximately \u003cstrong\u003e2.7 times the radius\u003c\/strong\u003e for a solid marble that rolls, because it also stores energy in its rotation. With two loops of different radii, you can verify that the small circle can be cleared from a much lower starting point than the large one.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003ch3 class=\"aa-title\"\u003eWhat this demonstrator brings\u003c\/h3\u003e\n\n\u003cdiv class=\"aa-ben\"\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e✦\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eA quantitative experience\u003c\/span\u003e\u003cspan class=\"ds\"\u003eThe starting height can be varied step-by-step: you look for the passage threshold rather than just watching.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e◆\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eTwo radii to compare\u003c\/span\u003e\u003cspan class=\"ds\"\u003eThe double loop places a large and a small circle side by side: the effect of the radius is immediately obvious.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e➤\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eTwo marbles, one lesson\u003c\/span\u003e\u003cspan class=\"ds\"\u003eSteel or plastic, same diameter: the comparison proves that mass does not play a role in the passage condition.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e✦\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eV-rail for guidance\u003c\/span\u003e\u003cspan class=\"ds\"\u003eThe V-profile of the aluminum keeps the marble on its trajectory for reproducible trials.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e◆\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eControlled finish\u003c\/span\u003e\u003cspan class=\"ds\"\u003eThe catching net stops the marble at the end of the run: no chasing under the tables.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-b\"\u003e\n\n\u003cspan class=\"ic\"\u003e➤\u003c\/span\u003e\n\u003cdiv\u003e\n\n\u003cspan class=\"tt\"\u003eNo external energy\u003c\/span\u003e\u003cspan class=\"ds\"\u003eThe only source of movement is gravity: the object works everywhere, without batteries or plugs.\u003c\/span\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-des\"\u003e\n\n\u003cp class=\"t\"\u003eThe laboratory classroom, an elegant version\u003c\/p\u003e\n\n\u003cdiv class=\"x\"\u003e\n\n\u003cp\u003eIn the high schools of yesteryear, physics cabinets lined up wood-and-brass demonstration apparatuses designed so that an entire class could see the phenomenon from the back of the room. This loop track follows in that tradition: a sturdy \u003cstrong\u003ewooden base\u003c\/strong\u003e, neat \u003cstrong\u003ealuminum\u003c\/strong\u003e rails, and a path that can be read from a distance.\u003c\/p\u003e\n\n\u003cp\u003eBut its real wealth lies elsewhere: it invites you to \u003cstrong\u003emeasure\u003c\/strong\u003e. Identify the starting height, note the result, try again a little lower, compare the large and small loops, swap the steel marble for the plastic one. In half an hour, students retrace the intellectual path of the scientists who founded mechanics: observe, conjecture, verify. And at home, the object keeps that little thrill intact when the marble hesitates at the summit.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-steps\"\u003e\n\n\u003ch4\u003eFour-step protocol\u003c\/h4\u003e\n\n\u003cdiv class=\"aa-step\"\u003e\n\n\u003cspan class=\"aa-step-n\"\u003e1\u003c\/span\u003e\n\u003cdiv class=\"aa-step-c\"\u003e\n\n\u003cstrong\u003eInstall the stand.\u003c\/strong\u003e Place the base on a horizontal table, clear of the catching net. If necessary, check for levelness with a spirit level.\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-step\"\u003e\n\n\u003cspan class=\"aa-step-n\"\u003e2\u003c\/span\u003e\n\u003cdiv class=\"aa-step-c\"\u003e\n\n\u003cstrong\u003eMark the heights.\u003c\/strong\u003e Mark several starting points on the ramp (a small piece of repositionable tape is enough) and measure their height above the bottom of the loop.\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-step\"\u003e\n\n\u003cspan class=\"aa-step-n\"\u003e3\u003c\/span\u003e\n\u003cdiv class=\"aa-step-c\"\u003e\n\n\u003cstrong\u003eRelease without push.\u003c\/strong\u003e Place the marble on a mark and release it without pushing. Note whether it clears the loop, or both loops on the double version.\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-step\"\u003e\n\n\u003cspan class=\"aa-step-n\"\u003e4\u003c\/span\u003e\n\u003cdiv class=\"aa-step-c\"\u003e\n\n\u003cstrong\u003eCompare and conclude.\u003c\/strong\u003e Repeat with the other marble, then compare the measured threshold height to the theoretical value of 2.7 times the radius. The difference illustrates the role of friction.\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\n\u003ch3 class=\"aa-title\"\u003eComparison of the two versions\u003c\/h3\u003e\n\n\u003cdiv class=\"aa-cmp\"\u003e\n\n\u003ctable\u003e\n\n\u003cthead\u003e\n\n\u003ctr\u003e\n\n\u003cth\u003eCriterion\u003c\/th\u003e\n\n\u003cth\u003eSingle loop\u003c\/th\u003e\n\n\u003cth\u003eDouble loop\u003c\/th\u003e\n\n\n\u003c\/tr\u003e\n\n\n\u003c\/thead\u003e\n\n\u003ctbody\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eNumber of loops\u003c\/td\u003e\n\n\u003ctd\u003eOne\u003c\/td\u003e\n\n\u003ctd\u003eTwo, of different radii\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr class=\"hl\"\u003e\n\n\u003ctd\u003eRadius\/radii indicated\u003c\/td\u003e\n\n\u003ctd\u003eNot specified for this version\u003c\/td\u003e\n\n\u003ctd\u003e≈ 7 cm and ≈ 3.5 cm\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eRail\u003c\/td\u003e\n\n\u003ctd\u003eV-profile aluminum\u003c\/td\u003e\n\n\u003ctd\u003eV-profile aluminum\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr class=\"hl\"\u003e\n\n\u003ctd\u003eBase\u003c\/td\u003e\n\n\u003ctd\u003eWood, ≈ 40 cm\u003c\/td\u003e\n\n\u003ctd\u003eWood, ≈ 40 cm\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eMarbles (manual)\u003c\/td\u003e\n\n\u003ctd\u003eSteel and plastic, Ø 2.5 cm\u003c\/td\u003e\n\n\u003ctd\u003eSteel and plastic, Ø 2.5 cm\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr class=\"hl\"\u003e\n\n\u003ctd\u003eKey experiment\u003c\/td\u003e\n\n\u003ctd\u003eFind minimum passage height\u003c\/td\u003e\n\n\u003ctd\u003eCompare radius effect on threshold\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eRecommended audience\u003c\/td\u003e\n\n\u003ctd\u003eDiscovery, middle school, office\u003c\/td\u003e\n\n\u003ctd\u003eHigh school, higher ed, enthusiasts\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\n\u003c\/tbody\u003e\n\n\n\u003c\/table\u003e\n\n\n\u003c\/div\u003e\n\n\u003cp\u003eWant to explore other mechanical phenomena? Our \u003ca href=\"\/collections\/physique-et-mouvement\"\u003ephysics and motion\u003c\/a\u003e collection brings together pendulums, motors, and demonstrators that ideally complement this track.\u003c\/p\u003e\n\n\u003cdiv class=\"aa-info\"\u003e\n\n\u003cp\u003e\u003cstrong\u003eGood to know:\u003c\/strong\u003e the loop radii and marble diameters are those indicated in the \u003cstrong\u003emanufacturer's manual\u003c\/strong\u003e; the base length is estimated from a photo. The manufacturer does not specify the total height, weight, or whether the device is delivered pre-assembled.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-tip\"\u003e\n\n\u003cp\u003e\u003cstrong\u003eTip:\u003c\/strong\u003e film the passes in slow motion with a smartphone placed facing the loop. Frame by frame, you can clearly see the marble slow down at the summit, and sometimes lift slightly off the rail just before stalling: an excellent aid for an experimental report.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003ch3 class=\"aa-title\"\u003eTechnical specifications\u003c\/h3\u003e\n\n\u003cdiv class=\"aa-sp\"\u003e\n\n\u003ctable\u003e\n\n\u003ctbody\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eType\u003c\/td\u003e\n\n\u003ctd\u003eDemonstration loop track (centripetal force)\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eVersions\u003c\/td\u003e\n\n\u003ctd\u003eSingle loop or double loop\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eRails\u003c\/td\u003e\n\n\u003ctd\u003eAluminum, V-profile\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eLoop radius (double version)\u003c\/td\u003e\n\n\u003ctd\u003e≈ 7 cm and ≈ 3.5 cm (manual)\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eMarbles (manual)\u003c\/td\u003e\n\n\u003ctd\u003e1 steel marble and 1 plastic marble, Ø 2.5 cm\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eBase\u003c\/td\u003e\n\n\u003ctd\u003eWood\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eBase length\u003c\/td\u003e\n\n\u003ctd\u003e≈ 40 cm (photo estimate)\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eFinish\u003c\/td\u003e\n\n\u003ctd\u003eMarble catching net\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eOperation\u003c\/td\u003e\n\n\u003ctd\u003eGravity, no power supply\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eConcepts covered\u003c\/td\u003e\n\n\u003ctd\u003eEnergy conservation, centripetal force, minimum speed at summit\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\u003ctr\u003e\n\n\u003ctd\u003eHeight \/ weight\u003c\/td\u003e\n\n\u003ctd\u003eNot provided\u003c\/td\u003e\n\n\n\u003c\/tr\u003e\n\n\n\u003c\/tbody\u003e\n\n\n\u003c\/table\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-warn\"\u003e\n\n\u003cp\u003e\u003cstrong\u003ePrecautions:\u003c\/strong\u003e the marbles are \u003cstrong\u003esmall parts\u003c\/strong\u003e: not recommended for children under 3; with children, an adult must always supervise the experiment. The steel marble can damage floors or fragile objects if dropped: work over a table. Do not bend the rails, as their shape is critical to successful runs.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003cdiv class=\"aa-gift\"\u003e\n\n\u003ch3\u003eA gift for minds that want to understand\u003c\/h3\u003e\n\n\u003cp\u003eThis demonstrator will delight a \u003cstrong\u003ephysics teacher\u003c\/strong\u003e who wants to refresh their lessons, a high school or prep school student, a science club, or a parent who enjoys conducting experiments with their teenagers. It is also an original gift for a mechanical engineer or a roller coaster enthusiast.\u003c\/p\u003e\n\n\u003cp\u003eTo complete the set, discover the entire selection of \u003ca href=\"\/collections\/objets-scientifiques\"\u003escientific objects from The Lab\u003c\/a\u003e or a puzzle from our \u003ca href=\"\/collections\/casse-tetes-et-bureau\"\u003epuzzles and office\u003c\/a\u003e collection.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003ch3 class=\"aa-title\"\u003eFrequently asked questions\u003c\/h3\u003e\n\n\u003cdiv class=\"aa-faq\"\u003e\n\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eShould I choose the single or the double loop?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eIt all depends on what you want to show. The \u003cstrong\u003esingle loop\u003c\/strong\u003e is enough to introduce centripetal force and search for the minimum starting height: it is the most readable version for a first discovery or for an office. The \u003cstrong\u003edouble loop\u003c\/strong\u003e adds a valuable comparative dimension: with a large circle of approximately 7 cm in radius and a small one of 3.5 cm, it shows concretely that the passage threshold depends on the radius. For use in class, in a science club, or for an enthusiast who likes to experiment, the double version offers significantly more experimental scenarios.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eWhat are the two marbles provided for?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eAccording to the manual, the demonstrator comes with a \u003cstrong\u003esteel marble\u003c\/strong\u003e and a \u003cstrong\u003eplastic marble\u003c\/strong\u003e of the same diameter, 2.5 cm. Comparing them illustrates a result that is often surprising: the condition for passing the summit does \u003cstrong\u003enot depend on the mass\u003c\/strong\u003e. Indeed, mass appears on both sides of the energy and force equations, and cancels out. In practice, slight differences may appear because the lighter marble is more sensitive to friction and small imperfections in the rail. Discussing these differences is one of the educational benefits of the experiment, which teaches how to distinguish between a theoretical model and a real-world measurement.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eFrom what height should the marble be released?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eThe theory provides a clear guideline. For an object sliding without friction, the start must be at least \u003cstrong\u003e2.5 radii\u003c\/strong\u003e of the loop, measured from the lowest point of the circle. For a solid marble that rolls, the energy spent on its own rotation raises the threshold to approximately \u003cstrong\u003e2.7 times the radius\u003c\/strong\u003e. With a 7 cm radius loop, this represents slightly less than 19 cm of starting height. Real friction increases this value further: this is the whole point of measuring it and comparing it to the calculation.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eWhat academic level is the demonstrator suitable for?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eIt adapts to many levels. In \u003cstrong\u003emiddle school\u003c\/strong\u003e, one simply observes the link between height and speed and formulates hypotheses. In \u003cstrong\u003ehigh school\u003c\/strong\u003e, it illustrates the conservation of mechanical energy and forces in circular motion. In \u003cstrong\u003eprep school or university\u003c\/strong\u003e, it allows one to explore the rotational energy of the marble and the analysis of friction. It also works very well in scientific outreach or at home with curious teenagers. With young children, the presence of an adult is essential, as the marbles are small parts to be kept out of reach of children under 3.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eWhat is the net at the end of the rail for?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eThe \u003cstrong\u003ecatching net\u003c\/strong\u003e stops the marble at the end of its run. Without it, a marble launched at full speed would leave the base and roll on the table, or even fall to the floor. It makes series of tests much more fluid: you retrieve the marble in the same place each time, note the result, and start again immediately. It is also a welcome safety feature with the heavier \u003cstrong\u003esteel marble\u003c\/strong\u003e, which could damage wood flooring or hit a fragile object if it falls. Simply keep the space in front of the net clear so the marble can enter freely.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eWhy V-shaped rails?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eV-profile\u003c\/strong\u003e creates two points of contact between the marble and the rail. The marble is thus naturally centered and guided throughout the length of the path, including in the inverted part of the loop, where a flat rail would let it drift laterally. This guidance improves the \u003cstrong\u003ereproducibility of trials\u003c\/strong\u003e: at the same starting height, the marble follows the same trajectory from one launch to the next, which is essential for measuring a passage threshold. \u003cstrong\u003eAluminum\u003c\/strong\u003e, being light and rigid, retains its shape well. Regular dusting with a dry cloth is enough to preserve the quality of the roll.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\u003cdetails class=\"aa-q\"\u003e\n\u003csummary\u003eIs the demonstrator delivered assembled?\u003c\/summary\u003e\n\u003cdiv class=\"aa-a\"\u003e\n\n\u003cp\u003eThe manufacturer \u003cstrong\u003edoes not specify\u003c\/strong\u003e whether the device is shipped fully assembled or if certain elements, such as the net or the rails, must be attached to the base upon receipt. We prefer not to claim anything we cannot guarantee. The photos show a simple assembly consisting of the \u003cstrong\u003ewooden base\u003c\/strong\u003e, the aluminum rails, and the catching net, without any mechanism or electronics. If this information is decisive for you, for example to prepare a lab session for a specific date, contact us before your order and we will respond with the elements we have available.\u003c\/p\u003e\n\n\n\u003c\/div\u003e\n\n\u003c\/details\u003e\n\n\u003c\/div\u003e\n\n\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Atelier Atypique","offers":[{"title":"Simple loop","offer_id":54860800688451,"sku":"1005012000667123-single lap-CN","price":243.0,"currency_code":"USD","in_stock":true},{"title":"Double loop","offer_id":54860800655683,"sku":"1005012000667123-double circles-CN","price":243.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0231\/3365\/0991\/files\/S60be848bb0ff4f158758504549a17fa95.webp?v=1791061033","url":"https:\/\/atelier-atypique.com\/products\/centripetal-force-experiment-demonstrator-wooden-metal-roller-model-for-science-education-and-classroom-teaching-k1kf","provider":"Atelier Atypique","version":"1.0","type":"link"}