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Why is the wetbulb thermometer read lower than The dry bulb thermometer?
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How much does an instant read thermometer cost?
The price of an instant read thermometer varies with the brand and retailer of the thermometer. Basic models can cost an average low of about å£2.50. The average high cost of an instant read thermometer is å£100.
Why are there two thermometers in a hygrometer?
A hygrometer is used to measure relative humidity. The two thermometers in a hygrometer are different in that one is a "regular" thermometer and the other has some batting (a wrap) around the bulb that is kept wet. The thermometers are called a dry-bulb thermometer and a wet-bulb thermometer, respectively. The dry-bulb thermometer measures "regular" or ambient air temperature. The wet-bulb thermometer will measure a cooler temperature (usually) because moisture evaporating from the wrap around its bulb will cool it down below ambient temperature. Below zero, the wrap freezes and the wet-bulb thermometer will read a higher temperature (usually) than its dry-bulb companion. The dry-bulb thermometer will tell us the actual ambient temperature of the air. It's a very necessary baseline. There is a maximum amount of moisture that air at a given temperature will hold. (Higher air temperatures will allow air to hold more moisture and lower air temperatures will not allow as much.) What we need to know is what fraction (the percentage) of moisture the air is holding relative to the maximun it can hold. That's why we call it relative humidity. It is the wet-bulb reading that is critical now. The hygrometer looks at the difference between the dry- and wet-bulb temperatures. This number, the difference, is looked up on a psychrometric chart, and for a given ambient temperature and a given temperature difference, there is only one relative humidity that will be possible. The psychrometric chart is a calibrated "graph" that has been drawn up from precise laboratory measurements of the way the two thermometers will react for a given ambient temperature and a given temperature difference (which means a specific relative humidity). A link is provided to the Wikipedia article on the hygrometer so you can see some pics and do some additional reading.
How does Mercury within a thermometer change?
The temperature in a Mercury-based thermometer is read by the level of Mercury found in the thermometer. As Mercury heats up, it expands, therefore raising the level of the Mercury of which we see as a higher temperature. On the other end, as the temperature falls, the Mercury contracts and reads at a lower temperature.
Why you need to prevent the Mercury of thermometer from falling back with the constriction?
So they can read the thermometer
What is immersion thermometer?
A total immersion thermometer is one that has been calibrated to read correctly when the entire thermometer is submerged in a homogeneously temperated liquid/medium.
What cause the wet bulb thermometer to read lower than the dry bulb thermometer?
because the water causes the temperature to be lower
Why is it important to immerse the entire bulb of the thermometer in the substance whose temperature is being measured?
if you dont put the whole bulb in, then the thermometer cant read the temperature accurately.
How hot does a 75 watt light bulb get?
When measured with an infrared thermometer it read 169.9 degrees F.
What causes the thermometer with the wet sock to read lower than the thermometer with the dry bulb?
The rate of evaporation of water from the wet side, this is how relative humidity is measured. As the water evaporates it effectivly 'uses' some of the heat energy which would otherwise be heating the thermometer. The higher the relative humidity (water saturation of the air) the less water can evaporate and the lower the difference between the wet and dry side.
How hot does a 75 watt bulb get?
When measured with an infrared thermometer it read 169.9 degrees F.
What will the mercury thermometer show when it is kept in ice?
The question must be asked carefully. If the thermometer is in water ice and there is no liquid water, and there is one atmosphere of pressure, the thermometer can read anything from the freezing point of water and lower, depending on the range of the thermometer. If the thermometer is in a stable mix of water and ice, it will read the freezing point of water.
What are precautions that are to taken while measuring the temperature in clinical thermometer?
the mercury should be at normal body temperature level before using it the thermometer should be cleaned after use with normal water the bulb of the thermometer should not be touched
Does a forehead thermometer read higher or lower than a rectal thermometer on a 2 month old baby?
At all ages rectal temperature is higher than skin temperature.
How do you read a laboratory thermometer?
you look at the sticks on the sidething
Where is the capillary tube and bulb in a thermometer?
The capillary tube is the hollow opening inside the thermometer that the liquid rises or lowers in so that you can read the temperature. The bulb is the bottom portion that holds the liquid and the part you use for contact to get a temperature reading. Calvin B.
How do you use hygrometers?
Fill the water bottle and screw it on to the instrument. Then hang the hygrometer (by the loop at the top) on a wall or a tree, for instance, for at least five to 10 minutes before taking the measurements. Ideally the instrument should be in a well-shaded spot or in a Stevenson screen (refer to "Making your own weather station" in Section 4: Contacts and further information). The instrument contains two alcohol-in-glass thermometers with a scale of minus 10 to plus 110 degrees Celsius, in 1 degree increments. The end of the 'wet-bulb' thermometer is covered with a damp cloth dipped in water. The other thermometer is the 'dry-bulb'. 6 Record the wet-bulb and dry-bulb temperatures. 6 Calculate the wet-bulb depression - the dry-bulb temperature minus the wet-bulb temperature. 6 Determine the relative humidity (%) using the table (reverse page). Read down from the wetbulb depression and across from the dry-bulb temperature. do's and don'ts Be careful with the instrument. The thermometers are made of glass and can easily break. Empty the water bottle before returning the hygrometer to its box. how it works The hygrometer works on a similar principle to the whirling psychrometer. The main difference is that the hygrometer is not rotated, so evaporation from the damp cloth around the wet-bulb thermometer occurs more slowly.
We read the temperature on what?
A thermometer.
