Photoacoustic spectroscopy Photoacoustic spectroscopy Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection. The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk. The absorbed energy from the light causes local heating, generating a thermal expansion which creates a pressure wave or sound. Later Bell showed that materials exposed to the non-visible portions of the solar spectrum (i.e., the infrared and the ultraviolet) can
In the House of Stone and Light (album) As stated in the EPK, "Shape the Invisible" is Page's favorite on his debut album. As described by him in his video EPK: "My favorite song is 'Shape the Invisible', purely because of what the lyrics say. I was reading a book about Leonardo DaVinci and he mentioned that this shape the invisible in a sentence, and I thought what a great title. And at the time I wrote the song, there is as there always is trouble in the world, and I really wrote it as a wish song." Also stated in the EPK by Page, about the song