Transcript Diffusion & Osmosis

Diffusion & Osmosis
Diffusion
The movement of molecules
from an area in which they are
highly concentrated to an
area in which they are less
Concentrated.
 requires
NO ENERGY.
Concentration
How crowded the solute is in
the solution
 If
the solute is more crowded then
the concentration is higher.
 If
the solute is more spread out then
the concentration is lower.
Diffusion of Perfume in the
classroom
Who smelled the
perfume first?
Who smelled it
last?
Diffusion of Food Coloring in Water
How did the temperature of the water affect
the speed of diffusion?
How could you explain this observation?
Osmosis
 The
diffusion of water across a
semi- permeable membrane.
 Requires
NO ENERGY.
Semi-Permeable Membrane
A
membrane that allows only certain
materials to cross it
 Water
passes through pores in the
membrane
Osmosis Video
http://highered.mcgrawhill.com/sites/0072495855/student_vi
ew0/chapter2/animation__how_osmos
is_works.html
Movement of Water
 Why
does water move from less
concentrated solution to the more
concentrated solution?
Isotonic Solution
A
solution that causes no change in
the size of the cell
 Why
do you think it causes no change
in the size of the cell?
Hypertonic Solution
 Has
more dissolved particles outside
the cell then inside the cell
 Meaning:
Hyper: more than normal
 Tonic=Dissolved particles

A
solution that causes a cell to
shrink because of Osmosis.
Hypotonic Solution
 Has
less dissolved particles outside
the cell then inside the cell
 Meaning:
Hypo: less than normal
 Tonic=Dissolved particles

A
solution that causes a cell to swell
because of Osmosis.
Summary



Diffusion is the movement of molecules
from an area of higher concentration to an
area of lesser concentration.
Osmosis is the movement of water thru a
semi-permeable membrane.
Both do not require NO ENERGY!