She explains how the muscular vocal folds create the vibrations which are then modified by the rest of the vocal tract to make the final sound. The hotter they get, the more radiation is given off. The science of thermography uses special detectors which only pick up the infrared or heat part of the E-M spectrum. Just like a regular camera picks up light energy, infrared cameras detect the waves of heat energy emanating from a warm object. Also like a camera, these heat scanners can either produce still photographs or video images.
Thermography is used in many different applications.
In medicine, it's used to tell where malignancies or infections lie hidden below the skin. Geologists use it to analyze different mineral deposits from the air and utilities use it to take heat prints of a house to find warm air leaks in the winter. Have the students research some of the unusual ways that animals use infrared light to sense the world around them. Landsat photographs for different regions are available through a variety of sources including NASA, The USGS and a variety of commercial sources. Have students compare and contrast the distribution of different types of landcover based on the infrared images.