Differential scanning calorimetry (DSC) is a thermal analysis technique that measures changes in heat capacity of a sample as it undergoes physical transformations like phase transitions. DSC detects transitions by measuring the difference in heat flow between a sample and reference material as both are heated or cooled. It is used in industries like pharmaceuticals, polymers, and food to study properties like melting points and glass transitions. DSC works by tracking changes in heat capacity of a sample as temperature varies, allowing detection of transitions involving energy changes.