{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.acoustic-mirror","code":"thing-q444789","url":"https://ver.cy/models/thing/q444789/","name":"acoustic mirror","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.5","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.BLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A large concave reflector, commonly of concrete, built before radar to warn of approaching aircraft by concentrating their sound at a listening point; developed in Britain from the First World War against airships, with examples such as those at Denge. Development was abandoned in the mid-1930s in favour of radar, whose Chain Home network entered operational service from 1938.","purpose":"Let an agent describe acoustic mirrors historically, explain how they worked, and point to heritage records of surviving examples.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Passive acoustic detection, before radar; an early 1915 example was cut into chalk.","Limited range, affected by wind and noise; faster aircraft shortened the warning time.","Abandoned in favour of radar in the mid-1930s; Chain Home became operational from 1938."],"structure":{"bundles":[{"id":"principle","name":"Principle","description":"How it worked.","layers":[{"id":"acoustics","name":"Acoustics","description":"Sound focusing.","findings":[{"id":"principle","name":"Principle","description":"Focusing.","questions":[{"text":"How did the mirror focus sound?","kind":"definition"},{"text":"What sensor was used?","kind":"provenance"}]}]},{"id":"performance","name":"Performance","description":"Range and limits.","findings":[{"id":"performance","name":"Performance","description":"Range and conditions.","questions":[{"text":"What range did it achieve?","kind":"measurement"},{"text":"What limited it?","kind":"provenance"}]}]}]},{"id":"examples","name":"Examples","description":"Surviving mirrors.","layers":[{"id":"sites","name":"Sites","description":"Locations.","findings":[{"id":"site","name":"Site","description":"Place and type.","questions":[{"text":"Where are surviving mirrors?","kind":"provenance"},{"text":"What type are they?","kind":"provenance"}]}]},{"id":"dimensions","name":"Dimensions","description":"Size.","findings":[{"id":"dimensions","name":"Dimensions","description":"Values and source.","questions":[{"text":"What are their dimensions?","kind":"measurement"},{"text":"From which source?","kind":"provenance"}]}]}]},{"id":"history","name":"History","description":"Development and end.","layers":[{"id":"development","name":"Development","description":"Designers and dates.","findings":[{"id":"development","name":"Development","description":"Who and when.","questions":[{"text":"Who developed them and when?","kind":"provenance"},{"text":"Where were trials held?","kind":"provenance"}]}]},{"id":"replacement","name":"Replacement","description":"Radar.","findings":[{"id":"replacement","name":"Replacement","description":"Date and reason.","questions":[{"text":"When were they abandoned?","kind":"provenance"},{"text":"Why?","kind":"provenance"}]}]}]},{"id":"heritage","name":"Heritage","description":"Protection.","layers":[{"id":"listing","name":"Listing","description":"Status.","findings":[{"id":"listing","name":"Listing","description":"Status and number.","questions":[{"text":"Is it protected?","kind":"provenance"},{"text":"Under which listing?","kind":"provenance"}]}]},{"id":"access","name":"Access","description":"Visits.","findings":[{"id":"access","name":"Access","description":"Arrangements.","questions":[{"text":"Can the site be visited?","kind":"provenance"},{"text":"Under what arrangements?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["describe history and heritage"],"mustNot":["encourage trespass on protected or unsafe sites"],"requiresHuman":[]},"ethics":{"considerations":["heritage conservation"],"affectedParties":["visitors","landowners"]},"owners":{"steward":"the landowner or heritage body for each surviving mirror","roles":[],"masterSystems":["national heritage lists"]},"relations":[{"target":"Q1427940","type":"parent","note":"registry parent class"},{"target":"Q811979","type":"parent","note":"registry parent class"},{"target":"early warning system","type":"related","note":"military technology"},{"target":"radar","type":"related","note":"technology"},{"target":"sound focusing","type":"related","note":"principle"},{"target":"scheduled monument","type":"related","note":"heritage"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.acoustic-mirror","Wikidata: Q444789 (https://www.wikidata.org/wiki/Q444789)","heritage list entry: national heritage list number for scheduled examples"]},"properties":{"applicability":"required","items":["bowl diameter: commonly about 3-4 m; Denge about 6.1 and 9.1 m - the Denge wall is about 61 m long"]},"recognition":{"applicability":"required","items":["Concave concrete dishes or long curved walls on coastal sites","Large concave concrete dishes or curved walls facing out to sea."]},"capabilities":{"applicability":"required","items":["explain how they worked","describe types and surviving examples","describe their replacement by radar","point to heritage protection"]},"hazards":{"applicability":"required","items":["Structural decay","Access risks at coastal sites"]},"interfaces":{"applicability":"required","items":["Heritage protection law for scheduled monuments"]},"context":{"applicability":"required","items":["Historically, early warning of enemy aircraft; today heritage and education.","dish mirrors","wall mirrors"]}},"sources":[{"title":"Q444789","url":"https://www.wikidata.org/wiki/Q444789","note":"identity of the registry item, labels and sitelinks"},{"title":"Acoustic mirror","url":"https://en.wikipedia.org/wiki/Acoustic_mirror","note":"general description of the subject"},{"title":"Three acoustic early warning devices 2360m east of Jack's Court","url":"https://historicengland.org.uk/listing/the-list/list-entry/1005119","note":"Denge dimensions, focusing principle, range up to 25 miles, weather limitations, chalk prototype and radar replacement by 1936."},{"title":"World War I early warning acoustic mirror 60m east of Boulby Barns Farm","url":"https://historicengland.org.uk/listing/the-list/list-entry/1020760","note":"1916 construction, Zeppelin-warning role, smaller mirrors and the effect of increasing aircraft speed."},{"title":"Acoustic Sound Mirrors at Greatstone-on-Sea, Lydd","url":"https://heritage.kent.gov.uk/Monument/MKE3769","note":"Denge construction dates, 20 ft and 30 ft dishes, 200 ft wall and condition-dependent detection range."}],"openQuestions":[],"resources":{"spec":"/models/things/publications/thing-q444789/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q444789/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-10-21T21:05:06Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-22T10:21:31+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass"},"score":1.0}}