3. It takes place when stomata opens for gas
exchange while photosynthesis .
It helps the plants cool down as it absorbs
the heat when it evaporates(same principle as
that of when we sweat).
It also creates suction pull, which leads the
water from roots in the xylem rise up. BUT
HOW ????????????
4.
5. It is the attraction of
two molecules of the
different kind.
It may be because of
bonding .
When opposite
charges attract each
other adhesion may
take place.
Like the water is
clinging to the leaf.
6. When water is poured on clean glass,
it tends to spread, forming a thin,
uniform film over the glasses surface.
This is because the adhesive forces
between water and glass are strong
enough to pull the water molecules
out of their spherical formation and
hold them against the surface of the
glass, thus avoiding the repulsion
between like molecules.
7. This is the
attraction of
molecules of same
type.
The attractive
forces exist
between molecules
of same substance.
Water droplets are
formed because of
cohesive forces.
8. This theory was proposed by an Irish
botanist H.H. Dixon and John Joly (in 1894).
They said that water is pulled from up, and
not pushed from down .There are 2
important things of this theory. They are:
Cohesion of water and adhesion between
water and xylem tissues
Transpirational pull
10. As the water molecules attract
each other (by cohesion) they
cannot be easily separated away
from each other.
Further, there is attraction
between water molecules and the
inner wall of xylem .
So , one can determine that water
cannot be pulled away because of
strong adhesive and cohesive
forces between water and xylem
and water and water respectively.
11.
12. It is the pulling force
responsible for lifting
the water. As water is
lost in form of water
vapor to atmosphere
from the stomata,
there is a negative
pressure created in
the cells of leaves or
it can be said that
the concentration of
water becomes
less(in the leaves).
