1 Size-Tornadoes can vary widely in size. 2  A typical tornado in the United States is around 500 feet across, but some may be as narrow as just a few feet across or as large as a mile wide. 3  Wind Speed-The wind speed of a tornado can vary from 65 to 250 miles per hour.
It is always used in conjunction with a means to determine at what pressure blood flow is just starting, and at what pressure it is unimpeded. Manual sphygmomanometers are used in conjunction with a stethoscope. The word comes from the Greek ÏÏÏÎ³Î¼ÏÏ (sphygmos, pulse), plus the scientific term manometer (pressure meter).
Hygrometer, instrument used in meteorological science to measure the humidity, or amount of water vapour in the air. Several major types of hygrometers are used to measure humidity. 1  Mechanical hygrometers make use of the principle that organic substances (particularly finer substances such as goldbeaterâs skin [ox gut] and human hair) contract and expand in response to the humidity. Contraction and expansion of the hair element in a mechanical hygrometer causes the spring to move the needle on the dial.