{"product_id":"bell-in-vacuum-demonstration-set","title":"Bell in Vacuum Demonstration Set","description":"\u003ch2\u003eYou need a vacuum pump, and we do not sell one\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eRead this first: this is the bell jar, plate and electric bell. The vacuum pump is a separate item, it is not included, and we do not currently stock it. Without a pump this apparatus does nothing.\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe supplier specifies vacuum pump SER1014149. That is not on our site. If you already have a working laboratory vacuum pump this set will work with it; if you do not, buy the pump first or ask us to quote one before you order this.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat the demonstration shows.\u003c\/strong\u003e A ringing bell sits sealed inside the jar. As air is pumped out, the sound fades and eventually disappears while the striker is plainly still moving. Sound needs a medium; light does not. It is one of the few physics demonstrations where students watch a thing happen and cannot argue with it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eOne thing the supplier is unclear about.\u003c\/strong\u003e The product name says \"with Plate \u0026amp; Bell - Electric\", but their own description talks about a ringing alarm clock under the jar. We do not know whether the sound source shipped is an electric bell, a clock, or both, so we are not going to describe it as either. Ask us and we will confirm exactly what is in the box before you order.\u003c\/p\u003e\u003cp\u003e$200.00. Made for demonstration rather than class sets - one per science department.\u003c\/p\u003e","brand":"MTA Essentials","offers":[{"title":"Default Title","offer_id":53793020936555,"sku":"EVSER1052591","price":200.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0963\/2795\/8891\/files\/ser1052591_bell-in-vacuum-with-plate-038-bell-8211-electric.webp?v=1788357168","url":"https:\/\/megaofficesupplies.com.au\/products\/bell-in-vacuum-demonstration-set","provider":"Mega Office Supplies","version":"1.0","type":"link"}