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The boiling point of the distillate is normally the temperature of the vapour. If the bulb of the thermometer is placed too high, above the sidearm leading to the condeser, the entire bulb will not be heated up by the vapour of the distillate, and the temperature will be too low. however, if the bulb of the thermometer is placed too low, too near to the surface of the boiling water, the thermometer will show a too-high reading.Thus, the bulb of the thermometer should be placed at the sidearm or just below the sidearm in order to obtain an accurate reading of the distillation. Source: http://books.Google.com.sg/books?id=qHoWToUx1uYC&pg=PA86&lpg=PA86&dq=why+is+the+bulb+of+the+thermometer+placed+at+the+sidearm&source=bl&ots=JBLp_O9h3d&sig=cY86Ubsrci1WpGedNfoU9x8GovE&hl=en&ei=1yRPSoO1JISIsgP02K2XBw&sa=X&oi=book_result&ct=result&resnum=1
It is swung through the air to speed up evaporation of water from the wet bulb thermometer.
Because you need to measure the temperature of water, not the air.
Because you need to measure the temperature of water, not the air.
It is cooling by evaporation
AnswerThere are a number of different types of thermometers, but all have two basic elements. First, they must have a temperature sensor (mercury, dissimilar metals, etc.) capable of detecting a change of temperature. Second, they must have a means (such as a scale) of measuring the degree of change.AnswerAlso there's a bulb isn't there? So there are: bulb, scale, colored alcohol (or w.e).
A wet bulb thermometer, simply has the sensitive bulb, dampened with water.A small muslin bag with wick attached, is placed over the bulb. The wick is placed in a small container of water, which must be periodically topped up.The water around the bulb evaporates, giving a cooling effect. As the water evaporates, more is drawn via the wick from the reservoir.The amount of evaporation, will depend on the water saturation already in the atmosphere. By comparing the temperature with a normal thermometer and reading the results in a table, the dew point can be found.
Quote: When the temperature falls, the column of mercury breaks at the constriction and cannot return to the bulb, thus remaining stationary in the tube. After reading the value, the thermometer must be reset by repeatedly swinging it sharply to shake the mercury back through the constriction. Unquote.
For current to flow through the lamp, there must be a potential difference (voltage) applied across opposite ends of that lamp.
A thermometer must be calibrated before use to avoid false readings.
the temparature of the liquid must be read while the thermometer is in the liquid.since the level of mercury drops as soon as the thermometer is taken out of the liquid ,therefore no need of the kink in thermometer.
The thermometer reading will change from reading the solution temperature.