The Mars Science Laboratory Curiosity rover has 10 science instruments, and each will be used in the coming weeks and months to help characterize the environment of Mars and determine if the planet ever had the potential for life.
The Sample Analysis at Mars (SAM) instrument is actually a combination of three individual instruments that will investigate the chemistry of the Martian surface. Roughly the size of a microwave oven, SAM will analyze samples taken by the robotic arm, looking for organic and inorganic compounds.
Jennifer Stern is one of the scientists using SAM to sort out geological signatures in the rock record from potential biological processes.