What are the parts of a sling psychrometer?
A sling psychrometer is an instrument that measures the relative humidity and dew point in an area. A sling psychrometer has two thermometers: a wet bulb and a dry bulb. The wet bulb has a cotton wick over the bulb of the thermometer, which is moistened with room temperature water.
What is the sling psychrometer used for?
A sling psychrometer can be used to find relative humidity, which is expressed as a percentage. It is computed by multiplying the amount of moisture in the air at a given temperature, dividing by the maxi- mum amount of moisture the air could contain at that same temperature, and then multiplying the quotient by 100.
How do you make a sling psychrometer?
Procedure
- Moisten a double layer of gauze with water.
- Use the rubber band to cover the bulb of one of the thermometers with the gauze.
- Secure the thermometer with gauze on one side of the plastic bottle and the other thermometer to the opposite side, using multiple pieces of strapping tape.
What is Kata thermometer?
The kata thermometer is a heated-alcohol thermometer; the time it takes to cool is measured and used to determine air current. It is useful for measuring low speeds in studies of air circulation.
How often should you replace the wick on a sling psychrometer?
Keeping the sling psychrometer clean is important for accurate measurements. Wipe the thermometers with vinegar to remove any dirt or any stubborn mineral deposits. The wet bulb thermometer wick should be changed once every four weeks if the instrument is used daily.
Why are human hairs often used in a hair hygrometer?
Strands of hair can relax and lengthen when the humidity increases, and then contract again when the humidity decreases. In fact, the rate of change in the length of hair strands is so dependable that they can actually be used as the basis for a hygrometer, a device that measures the humidity level in the air.
What are wet and dry-bulb thermometers used for?
An instrument to measure the dew point, relative humidity, and vapor pressure. The dry-bulb thermometer shows the current temperature, whereas the wet-bulb thermometer shows a somewhat lower temperature, the result of the latent heat of evaporation, which depends on the relative humidity of the air.
How do you calculate RH from dry and wet bulbs?
To determine relative humidity subtract the lower “wet bulb” temperature from the higher “dry bulb” temperature to determine the difference and compare to the chart.
What is Kata factor?
Kata-factor meaning A conversion factor, constant for a given kata thermometer, used to convert the measured time for a standardised drop in temperature into the environmental cooling rate. noun.
Why red alcohol is used in kata thermometer?
For the working temperature range, the meniscus or interface between the liquid is within the capillary. With increasing temperature, the volume of liquid expands and the meniscus moves up the capillary. Since these are transparent, the liquid is made more visible by the addition of a red or blue dye.
