{"product_id":"wimsha-wimshurst-machine","title":"Wimsha – The Wimshurst Machine \/ Induction Physics Sticker","description":"\u003cp\u003eWimsha, a bearded instrument-maker, works a pair of glass discs while a blue spark crackles between them.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eIn the early 1880s James Wimshurst, a London shipwright and amateur experimenter, perfected an influence machine: two insulating discs carrying metal sectors, turned in opposite directions on one axle. Neutralising brushes and collecting combs let a tiny starting charge on one disc induce opposite charge on the other, over and over, so the charge grows with each turn. No rubbing is involved, so unlike older friction machines it works reliably in damp weather and starts itself.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ grows by induction each turn\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eQ: charge stored on the collectors, usually Leyden jars (C)\u003c\/li\u003e\n\u003cli\u003eV = Q\/C: voltage across the spark gap (V)\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eThe energy comes from your arm: you do mechanical work turning the discs against the electrostatic attraction of the charges.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e The spark length depends on humidity, disc size and the jars; typical classroom machines give a few centimetres, tens of kilovolts.\u003c\/p\u003e\u003ch3\u003eOn the sticker\u003c\/h3\u003e\u003cp\u003eWimsha leans over two large glass discs on one axle, with curved arrows showing them turning in opposite directions and a cyan spark at the centre. Printed text: \u003cstrong\u003eWIMSHA\u003c\/strong\u003e with the line \u003cstrong\u003eINDUCTION\u003c\/strong\u003e. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"2\" × 2\" \/ White","offer_id":50964046938215,"sku":"16321325945225105079","price":4.99,"currency_code":"USD","in_stock":true},{"title":"3\" × 3\" \/ White","offer_id":50964046970983,"sku":"87085044789462303724","price":6.99,"currency_code":"USD","in_stock":true},{"title":"4\" × 4\" \/ White","offer_id":50964047003751,"sku":"37037121763124774183","price":8.99,"currency_code":"USD","in_stock":true},{"title":"6\" × 6\" \/ White","offer_id":50964047036519,"sku":"27222600349268195600","price":11.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/6760088974434096754_1200.jpg?v=1793658853","url":"https:\/\/pixelatedphysics.com\/fr\/products\/wimsha-wimshurst-machine","provider":"Pixelated Physics","version":"1.0","type":"link"}