GUSTOIMAGES / SCIENCE PHOTO LIBRARY GUSTOIMAGES / SCIENCE PHOTO LIBRARY
Thermometers. Three clinical thermometers each with a scale in both degrees Celsius and Fahrenheit. Each thermometer shows a different temperature reading, increasing from top to bottom. These devices consist of a narrow, sealed tube with a bulb of mercury at one end (at left). As the mercury warms, it expands up the tube in proportion to its temperature. The temperature can then be read off the mercury level against the scale.
Model release not required. Property release not required.