Helium Whistle by NASA
Listen closely to hear the whistling sound of superfluid helium-3 oscillating, getting louder and quieter. The oscillation occurs when the helium-3 is pushed through perforated membranes in a special container. UC Berkeley scientists used the world’s most sensitive microphone, which picked up sounds of the equipment, ground and building motion that you hear as background noise. The whistling sound was magnified so the human ear could hear it.