Why are glass thermometers not recommended?
Liquid in glass thermometers tend to be fragile and hence easily broken, can only be used where the liquid column is visible, cannot be used for surface temperature measurements, cannot be read from a distance and are unsuitable for high temperature measurements.
What liquid is in a glass thermometer?
Mercury
What liquid is in a Galileo thermometer?
The liquid in AcuRite Galileo Thermometers is 100% paraffin. The colored bulbs are filled with paraffin and 3.4% dye. The liquid is non-toxic.
Why do Mountaineers use alcohol thermometer?
Alcohol thermometers are used rather than mercury thermometers in very cold regions because alcohol has a lower freezing point than mercury. Pure ethanol freezes at -115 degrees C, while mercury freezes at -38 degrees C.
What are the uses of alcohol used in thermometer?
Ethanol-filled thermometers are used in preference to mercury for meteorological measurements of minimum temperatures and can be used down to −70 °C (−94 °F). The physical limitation of the ability of a thermometer to measure low temperature is the freezing point of the liquid used.
What are the advantages of alcohol thermometer?
A thermometer comparison
| advantages | disadvantages |
|---|---|
| Alcohol thermometer (compared to a mercury thermometer) | |
| lower freezing point (-114 C) | less durable (alcohol evaporates) |
| larger coefficient of expansion | alcohol can polymerise |
| less hazardous | fluid loss by evaporation hard to avoid |
Why thin glass is used in the bulb?
its made of glass with very thin walls to allow the heat from sample being measured to reach the liquid quickly for fast response and quick reading (improves the quickness of response by the thermometer). — has a vacuum above the liquid column so there is no resistance to the expanding liquid.
Why are clinical thermometer made of glass give two reasons?
Glass has a very low coefficient of thermal expansion. This is the reason why thermometer bulb or for a matter of fact entire thermometer is made up of glass. Due to low coefficient of thermal expansion, when the thermometer undergoes a large temperature change it will have minimal change in dimensions.
What are the advantages and disadvantages of thermocouple?
RTD Advantages and Disadvantages
| Sensor | Advantages | Disadvantages |
|---|---|---|
| Thermocouple | Simple Inexpensive Large variety Large temperature range Rugged « Self-powered » | Non linear Low voltage Require reference Less stable |
| RTD | More Stable More accurate More linear | Expensive Current source required Small Self heating Small base resistance |
Why the bulb is made of glass?
The resistance of the filament heats the bulb up. Eventually the filament gets so hot that it glows, producing light. so to store this gases in bulb a glass coatings are used. Also the glass is non reactive with glasses,hence the glass are used to electric bulb.
Why are clinical thermometer made of glass?
Clinical thermometers are made up of glass because glass has very low co efficient of thermal expansion it is a bad conductor of heat and it is transparent.
Which is an advantage of using a thermocouple instead of a liquid in glass thermometer?
Thermocouples have two major advantages over traditional thermometers: they can be used over much wider ranges of temperatures and are usually smaller. They do, however, have disadvantages as well. They require a precision voltmeter and the materials used to make them are often expensive.
Why only mercury is used in thermometer?
Most metals are good conductors of heat and they are solids at room temperature. Mercury is the only one in liquid state at room temperature. It’s used in thermometers because it has high coefficient of expansion. Hence, the slightest change in temperature is notable when it’s used in a thermometer.