The document discusses evaporation, humidity measurement, and condensation. It defines evaporation as a liquid turning into a gas due to increased energy, and discusses factors that affect the evaporation rate like temperature, vapor pressure, surface area, and time of evaporation. It also explains humidity measurement using water mixing ratio and relative humidity. Finally, it defines condensation as water changing from gas to liquid phases, and describes how it occurs in the atmosphere through cooling of warm air as well as at ground level as fog.

1. Frician Bernadette M. Muyco
• EVAPORATION
• HUMIDITY
MEASUREMENT
• CONDENSATION
FRICIAN BERNADETTE M.
MUYCO

3.  the process by which a liquid turns into a gas as a result of increased
energy in its particles, also called vaporization.
 describes the process of a liquid becoming a gas due to being heated.
Liquids, gases and solids can change their state due to the transfer of
energy involved in a change of temperature.
 This change of state can happen when the sun warms the surface of a
body of water.
 When water gets so hot it contains gas bubbles this is called boiling or
rapid vaporization rather than evaporation, whereas when water is
simmering it’s turning to steam at a much slower rate. The bonds
between the water molecules get broken down by the heat energy.

4.  Examples:
Boiling water to steam
Drying of clothes
When we sweat,the sweat
evaporates by the heat from our
body
Crystallization

6. 1. TEMPERATURE - the greater the temperature ->the greater will be the evaporation
2. VAPOUR PRESSURE – inversely proportional ->the lower the external pressure, the
lower the boiling point of the liquid->the greater the evaporation
3. SURFACE AREA – the greater the surface area of the liquid->the greater will be the
evaporation
4. MOISTURE CONTENT OF THE-FEED – some drug constituents undergo hydrolysis
readily in presence of moisture at high temperatures
- to prevent decomposition, the materials exposed to lower temperature initially,
then exposed to higher temperature for final concentration
5. TIME OF EVAPORATION – time of exposure is longer, the greater will be the
evaporation
6. FILM AND DEPOSITS – vegetable extracts are concentrated in steam pan, film may
be formed
- film reduced evaporating surface
- stirring is necessary

7. 1. EVAPORATING PANS (steam
jacketed kettle)
2. VAPOUR HEATED EVAPORATORS
WITH TUBULAR HEATING SURFACES

8.  Horizontal tube evaporator
 Climbing Film evaporator/rising
Film Evaporator
 Vertical tube evaporator
 Falling Film Evaporator

9. HUMIDITY
MEASUREMENT

10. WHAT IS HUMIDITY?

12. Water
mixing ratio

14. Ex. One cubic meter of air is dried out and found to
contain 0.006 kg of water. The amount of water in
saturated air, found from tables would have been 0.017
kg.
RH is 0.006 x100= 35.3 %
0.017

19. CONDENSATION

23. Condensation is the change of water from its gaseous form (water
vapor) into liquid water.
Condensation generally occurs in the atmosphere when warm air
rises, cools and looses its capacity to hold water vapor.
As a result, excess water vapor condenses to form cloud droplets.
The upward motions that generate clouds can be produced
by convection in unstable air, convergence associated with cyclones,
lifting of air by fronts and lifting over elevated topography such as
mountains.

24. Condensation also occurs at ground level. The difference
between fog and clouds which form above the Earth's surface
is that rising air is not required to form fog.
Fog develops when air having a relatively high humidity
comes in contact with a colder surface, often the Earth's
surface, and cools to the dew point.