This document discusses various physical properties of agricultural crops including size, shape, volume, density, roundness, sphericity, and porosity. Size is measured using tools like calipers and microscopes. Shape can be round, oblate, or irregular and influences packaging and sorting. Volume is measured by water displacement. Density is the ratio of mass to volume. Roundness and sphericity quantify how close a shape is to a perfect sphere. Porosity measures empty space between grains. Physical properties provide important information about crops.

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2. . Physical properties
 Basic physical property: size, shape, mass, surface
area, colour, appearance.
 Derived physical property:: volume, density,
roundness, roundness ratio, sphericity and porosity.

3. Size
 Size is measured in the form of diameter/ radius,
length and breadth, and length, breadth and
thickness.
 When the size can be expressed in two or three
dimensions, the major dimension is length and the
dimension perpendicular to length is breadth or width
and the dimension perpendicular to both length and
breadth is called the thickness or height.

4.  The measurement is done using vernier caliper, screw
gauge, travelling microscope, etc.,
 Normally a minimum number of 50 grains / samples
are measured and the mean is reported with the
standard deviation.

5.  The size of the grains increases with moisture content
at extreme conditions due to swelling.

6. Shape
 Shape is an important property to specify the
geometry of the crop.
 They are important for the design of packaging system
and sieve for grading/ separation.
 Following are some of the important shapes and
examples.

7. . Important shapes of agricultural
crops and examples.
 Round approaching spheroid like.
Round approaching
spheroid like.
eg. Lemon, apple
etc.
Oblate flattened at stem end
apex
eg. Pomegranate,
pumpkin
Regular horizontal section
approaches to a circle
eg. Grapes etc.
Irregular horizontal cross-
section departs from a
circle.

8. Roundness:
 it is the measure of sharpness of solid.
. Roundness =AP/AC
Where AP= largest projected area of object when it is
natural rest position (kernel)
Ac= area of smallest circumscribing circle
Roundness ration =r/R

9. Sphericity
 Isoperimetric property of a sphere:
Sphericity=di/dc
Where di-diameter of largest inscribed circle .
Dc= diameter of smallest circumscribed circle.

10. Volume
 Bulk volume:
 volume of the bulk materials including pore space
between granular pack.
 It is normally measured from the container or bin the
bulk grain occupies.

11.  True volume:
 Volume of the fruits / vegetables is measured by water
displacement method.
 Volume=(weight in air-weight in water)

12. porosity
 Porosity is defined as the percentage of volume of
inter-granular space to the circle volume of grain bulk.

13. Density
 Density is the ratio of mass to volume.
 Bulk density:the ratio of the grain mass divided by the
volume occupied by the grain kernels and the inter
granular spaces

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