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
Invisible Woman Invisible Woman The Invisible Woman (Susan "Sue" Storm-Richards), previously known as the Invisible Girl, is a fictional superheroine appearing in American comic books published by Marvel Comics. The character is a founding member of the Fantastic Four and was the first female superhero created by Marvel during the Silver Age of Comics. Sue Richards receives her powers by being exposed to a cosmic storm. Her primary power deals with light waves, allowing her to render herself and others invisible. She can also project powerful fields of invisible psionic energy which she uses for a variety of offensive and defensive effects.