Akademik

Thermometer

A device used to measure the temperature of gaseous, liquid or solid matter or of a chemical reaction such as fire. Temperature measurement is important to a wide range of activities, including industry, scientific research, and health care. In health care, thermometers are used to measure the temperature of the human body. They include the following types: Oral thermometers (those placed under the tongue) Rectal thermometers (those placed within the rectum) Multi-purpose thermometers (those that can be placed under the tongue, in the rectum or under the armpit) Eardrum thermometers (those placed inside the ear). Basal thermometers (highly sensitive thermometers placed under the tongue or in the rectum to measure slight temperature changes indicating that ovulation has taken place in a woman). Oral and rectal thermometers: A conventional oral or rectal thermometer consists of a sealed glass tube containing a liquid such as mercury. Imprinted on the tube is a temperature scale. When the temperature rises or falls, the mercury expands or contracts, causing it to move up or down the scale inside a tiny passageway. A narrow point along the passageway allows the mercury to move up the scale but prevents it from moving down until the thermometer is "shaken down" after use. The thermometer must maintain contact with the body for about four (4) minutes to yield an accurate reading. A rectal reading is usually slightly more accurate than an oral reading. New-fangled thermometers: Thermometers are also available with digital displays that facilitate easy reading of the temperature, beepers to signal when it is time to withdraw the thermometer, and flexible tubes to resist breakage. Manufacturers provide instructions for their use. Ear thermometers: Ear or more precisely eardrum thermometers measure temperature by reading infrared radiation emanating from eardrum tissue. They have three key advantages: {{}}The ability to measure temperature without coming in contact with the body; The ability to give a close estimate of the temperature of the brain (because of their proximity to the brain) as a true gauge of body temperature; and Their ability to provide a readout in two or three seconds. However, the accuracy of the eardrum thermometer has been questioned by some physicians. Whether it will supplant the usual oral or rectal thermometer remains to be seen. Basal thermometers: Basal thermometers measure minor temperature changes in women to indicate whether ovulation (the release of an egg for fertilization by sperm) has taken place. The temperature of women normally rises slightly when ovulation occurs and does not return to normal until menstruation begins. Basal thermometers are sensitive enough to monitor the slight changes in temperature. Taking temperature: Normal body temperature is considered to be 98.6 degrees Fahrenheit, although it may range between 97 and 99 degrees during the day. The temperature at the beginning of the day, when a person awakens, is called the basal temperature. A doctor should always be consulted if the temperature reaches 103 degrees Fahrenheit or more in a child and 104 to 105 degrees or more in an adult.

* * *

An instrument for indicating the temperature of any substance; often a sealed vacuum tube containing mercury, which expands with heat and contracts with cold, its level accordingly rising or falling in the tube, with the exact degree of variation of level being indicated by a scale, or, more recently, a device with an electronic sensor that displays the temperature without the use of mercury. SEE ALSO: scale. [thermo- + G. metron, measure]

- air t. gas t..

- axilla t. t. used by placing it in the armpit, with the arm held closely to the side. SYN: axillary t..

- axillary t. SYN: axilla t..

- clinical t. a small, self-registering t., consisting of a simple scaled glass tube containing mercury, used for taking the temperature of the body.

- differential t. SYN: thermoscope.

- gas t. a t. filled with dry air or a gas, the expansion or increased pressure of which indicates the degree of heat; used to measure high temperatures.

- resistance t. a device measuring temperature by the change of the electrical resistance of a metal wire. SYN: resistance pyrometer.

- self-registering t. a t. in which the maximum or minimum temperature, during the period of observation, is registered by means of a special appliance; in the clinical t. only the highest temperature is registered, usually by a steel bar above the column of mercury or by a segment of the mercury separated from the main column by a bubble of air; after the maximum temperature is registered, the bar or segment of mercury remains in place as the column of mercury contracts.

- spirit t. a t. filled with alcohol, used to measure extreme degrees of cold.

- surface t. a t. in the form of a disk or strip that indicates the temperature of the portion of the skin to which it is applied.

- wet and dry bulb t. SYN: psychrometer.

* * *

ther·mom·e·ter thə(r)-'mäm-ət-ər n an instrument for determining temperature that usu. consists either of a device providing a digital readout or of a glass bulb attached to a fine tube of glass with a numbered scale and containing a liquid (as mercury or colored alcohol) that is sealed in and rises and falls with changes of temperature

* * *

a device for registering temperature. A clinical thermometer consists of a sealed narrow-bore glass tube with a bulb at one end. It contains mercury, which expands when heated and rises up the tube. The tube is calibrated in degrees, and is designed to register temperatures between 35°C (95°F) and 43.5°C (110°F). An oral thermometer is placed in the mouth; a rectal thermometer is inserted into the rectum.

* * *

ther·mom·e·ter (thər-momґə-tər) [thermo- + -meter] an instrument for determining temperatures. In principle, it makes use of some substance with a physical property that varies in magnitude with temperature, to determine a value of temperature on some defined scale. See also scale and selected subentries thereunder.

Medical dictionary. 2011.