Show I I Air Bubbles Dea Un erwi o r oses NEW Streams Streams of bubbles rising something like Ilke those in H II carbonated drink are arc good earplugs earplugs ear car plugs against underwater noise They act like an insulating screen deadening a large amount of the noise Donald P. P Loye and William William Wil Vii liam Fred Arndt have reported in inthe inthe the Journal of the ilie Acoustical Society Society Society So So- of America The bubble screen they said proved effective at Pearl Harbor in hi insulating the entrance to a repair repair repair re re- pair dock against much underwater noise coming from other parts of the harbor The repair dock was used as a test area to measure the amount of noise made by machinery and and operation of the submarines It was vital to quiet down the United States subs to make it harder for forthe forthe forthe the Japanese to hear them Underwater Underwater Underwater Under Under- water noises from the other ships in the harbor interfered with such tests Loye and Arndt then with the United States navy underwater sound laboratory said the bub air ble screen unlike any kind of gate didn't have to be opened or closed to allow a sub to enter or leave the dock The mst first system for the bubble- bubble making used a pipe with small drilled holes with compressed air pumped into the pipe But this system system tem tern itself was noisy The best arrangement they said was a pipe with many small holes with the pipe covered with a loose- loose fitting sock This sock had a few rows of holes made by a sewing machine needle Air Mr coming coming corning com corn ing through the tiny holes mada made little lit tie tle noise and the bubble sere screw to had a sound insulation effect of 24 2 I decibels |