OverviewA thermometer is a useful aid used to measure body temperature. A thermometer is usually filled with mercury. Mercury in the tube rises when expanded by an increase in body temperature.
Update Date 7/10/2015
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.