A Sling PsychrometerA Sling Psychrometer
is used to measureis used to measure
relative humidity.relative humidity.
Get yours today!Get yours today!
Psychrometer Parts:Psychrometer Parts:
•Dry Bulb ThermometerDry Bulb Thermometer
•Wet Bulb ThermometerWet Bulb Thermometer
•Reservoir and StockingReservoir and Stocking
But why do we sling itBut why do we sling it
What happens to your skin when youWhat happens to your skin when you
sweat and then stand in a breeze?sweat and then stand in a breeze?
As the wet-bulb themometer goes through the airAs the wet-bulb themometer goes through the air
1. Water1. Water
2. Energy is2. Energy is
used; waterused; water
from liquid tofrom liquid to
3. Wet-bulb temperature goes down3. Wet-bulb temperature goes down
What influences howWhat influences how
much the wet-bulbmuch the wet-bulb
temperature goestemperature goes
Using our wet- andUsing our wet- and
dry-bulb temperatures,dry-bulb temperatures,
we can consult tableswe can consult tables
made by scientists…made by scientists…
……to determineto determine humidityhumidity andand saturation valuesaturation value..
Now we can calculate relative humidity!Now we can calculate relative humidity!
Partial Relative Humidity Chart for 30° CPartial Relative Humidity Chart for 30° C
Dry Bulb and Wet Bulb
Fortunately, we don’t have to do all this every time…Fortunately, we don’t have to do all this every time…
On the side of the psychrometer isOn the side of the psychrometer is
a sliding scale which calculatesa sliding scale which calculates
relative humidity for us.relative humidity for us.
Align the dry-bulb reading with theAlign the dry-bulb reading with the
wet-bulb reading. The arrow will pointwet-bulb reading. The arrow will point
to the relative humidity reading on theto the relative humidity reading on the
center scale. It’s easy!center scale. It’s easy!