{"product_id":"eisco-doppler-effect-demo-92db-buzzer-0-8m-tether","title":"Doppler Effect Demonstration Apparatus - Clear Classroom Audio","description":"\u003cp\u003eOur review of the Doppler Effect Demonstration Apparatus finds it to be a straightforward, effective classroom tool for physics labs and demonstrations. Designed to be swung on a 0.8 m tether, the unit uses a loud 92 dB buzzer so students can reliably hear the change in pitch as it passes; this clarity of the \u003cstrong\u003eDoppler effect\u003c\/strong\u003e is the single biggest reason to buy it. The kit is simple to operate, with an on\/off switch and a rugged ABS housing, though users should supply batteries and observe safety when swinging.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e92 dB buzzer:\u003c\/strong\u003e A loud tone that remains easy to hear when stationary and shows an audible frequency shift when swung for clear demonstrations.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.8 m tether:\u003c\/strong\u003e The 2 ft 8 in nylon cord gives enough radius to produce a noticeable Doppler shift while remaining manageable for classroom use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRugged construction:\u003c\/strong\u003e The buzzer housing and handle are made of ABS plastic, offering durability for repeated student use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimple switch:\u003c\/strong\u003e A built-in on\/off switch makes the apparatus easy to operate during lessons without additional controls.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eErgonomic handle:\u003c\/strong\u003e The ABS handle is about 8.5 in long and 1 in diameter, which provides a secure grip during demonstrations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThis apparatus is best for middle school, high school, and introductory college physics classes where instructors want a hands-on demonstration of sound frequency change due to relative motion. It suits teachers who prefer a compact, ready-to-use item rather than building a DIY rig from parts.\u003c\/p\u003e\n\u003cp\u003eIt is less appropriate for very young children unsupervised during swinging demonstrations or for applications requiring precise calibrated frequency data; in those cases, a lab instrument with measurement readouts would be more suitable.\u003c\/p\u003e\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eClear audible shift in pitch thanks to the \u003cstrong\u003e92 dB buzzer\u003c\/strong\u003e, making the Doppler effect easy for students to hear.\u003c\/li\u003e\n\u003cli\u003eDurable ABS housing and handle stand up to classroom handling and repeated demonstrations.\u003c\/li\u003e\n\u003cli\u003eSimple on\/off switch and a comfortable handle allow quick setup and safe operation with supervision.\u003c\/li\u003e\n\u003cli\u003eThe 0.8 m tether is long enough to produce a noticeable effect while staying convenient to use in typical classrooms.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eBattery not included, so instructors must supply the correct batteries before first use.\u003c\/li\u003e\n\u003cli\u003eAs a demonstration device it produces qualitative results only and is not intended for precision frequency measurement.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct\u003c\/td\u003e\n\u003ctd\u003eDoppler Effect Demonstration Apparatus\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBuzzer loudness\u003c\/td\u003e\n\u003ctd\u003e92 dB (when stationary)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTether length\u003c\/td\u003e\n\u003ctd\u003e0.8 m (2 ft 8 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHandle\u003c\/td\u003e\n\u003ctd\u003eABS handle, 8.5 in long, 1 in diameter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHousing\u003c\/td\u003e\n\u003ctd\u003eRugged ABS plastic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSwitch\u003c\/td\u003e\n\u003ctd\u003eSimple on\/off switch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBatteries\u003c\/td\u003e\n\u003ctd\u003eNot included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe Doppler Effect Demonstration Apparatus is a practical, low-friction teaching aid that delivers an unmistakable audible demonstration of moving-source frequency change. For physics instructors who need a durable, easy-to-use demo tool that students can hear across a classroom, it represents good value despite requiring separate batteries and not providing precision measurement.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it come with batteries?\u003c\/strong\u003e\u003cbr\u003eNo, batteries are not included; plan to supply the required batteries before use.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs the tether long enough for a clear Doppler effect?\u003c\/strong\u003e\u003cbr\u003eYes, the 0.8 m (2 ft 8 in) nylon cord produces a noticeable pitch shift while remaining practical for classroom demonstrations.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs it safe for student use?\u003c\/strong\u003e\u003cbr\u003eWith appropriate supervision and caution during swinging demonstrations it is safe; the handle and housing are rugged ABS but instructors should enforce a clear area.\u003c\/p\u003e","brand":"Eisco","offers":[{"title":"Default Title","offer_id":46512958341339,"sku":"B00YNT5J5K","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/71EoNhDtlsL._SL1500.jpg?v=1740065731","url":"https:\/\/gearmusthave.com\/products\/eisco-doppler-effect-demo-92db-buzzer-0-8m-tether","provider":"GearMustHave","version":"1.0","type":"link"}