OSMOSISBy : AMEER AZEEZ

OSMOSIS

By : AMEER AZEEZ BREESAM

Kutaisi, 2014

Osmosis is the net movement of water

molecules across a Partially-permeable membrane.

Water molecules move randomly with a certain amount of kinetic energy…

and we can say it the phenomenon in which the two solutions of two different concentrations are separated by the semi permeable membrane . the molecules of the water move from their higher concentration to their lower concentration till the concentration of both the solutions becomes equal .

Osmosis caused by a concentration difference of H2O

If a substance is dissolved in water, the kinetic energy of the

water molecules is lowered.

This is because some water molecules aggregate on the

surfaces of the other molecules…

For osmosis we talk about the potential water molecules have to move – the OSMOTIC POTENTIAL.

Distilled water has the highest potential (zero).

When water has another substance dissolved in it, the

water molecules have less potential to move. The osmotic

potential is NEGATIVE.

Water molecules always move from less negative to more

negative water potential.

Net osmosis

=LN MN

The osmotic potential of a cell is known as its WATER

POTENTIAL. For animal cells, the water potential is

the osmotic potential of the cytoplasm.

Enough water ordinarily diffuses in each direction through the red cell membrane per second to equal about 100 times the

volume of the cell itself

Yet normally the amount that diffuses in the two directions is balanced so precisely that (zero) net movement of water occurs . Therefore, the volume of the cell remains constant . However, under certain conditions , a concentration difference for water , can develop

across a membrane,

When this happens, net movement of water does occur across the cell membrane, causing the cell either to swell or shrink depending on the direction of the water movement

When your hands are immersed in dishwater for a long time, your skin looks bloated. This is an effect of osmosis.When you pour salt onto a slug, water diffuses and slug shrinks as a result of osmosis.When you cook food and put sauce in the liquid part of your dish, some part of the solute moves inside the solid part of the food you are cooking. The solid part could be an egg, piece of meat but the sauce is made of solute and not water, so it will move into the food.

…

Osmosis Examples in Daily Life

Osmosis also plays an important part in the body .

“It helps in the transfer of water and various nutrients between blood and fluid of cells”.

“Plants also use osmosis to take in water and minerals essential for its growth “ .

“Reverse osmosis is a type of osmosis which is used to convert sewage water into clean

drinking water”

In example on osmosis take a thistle funnel and cover its mouth with a parchment paper. and fill it with concentrated

sugar solution  place thistle funnel in a beaker containing water and mark the level of sugar solution in the stem.leave the apparatus undisturbed for 4-5 hoursyou will observe that the level of sugar solution in the stem rises and the level of water decreases as water passes through the parchment paper into the sugar solution. it because of osmosis

Thank you for your attention