What is an example of osmosis?

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aimeefarnum's profile pic

aimeefarnum | High School Teacher | (Level 2) Adjunct Educator

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Osmosis is diffusion of water across a semi-permeable membrane.  Salt is too big to pass through a cell membrane, but water molecules can fit.  Since everything wants to reach equilibrium, the only thing that can flow to create equal concentrations is water.

Real world examples of osmosis:

1.  Why we use saline solution for contact lenses - if you ever placed your contacts in pure water you will notice how uncomfortable it is the next day, or if you fail to rinse out your contact case it will get too salty.  Saline solution for contact lenses is the same concentration of salt water as your eye.

2.  Saline drips at the hospital - same ratio of salt water as is in your cells.

3.  Making french fries - more salt makes the french fries more crispy and less soggy.  This is done by pre soaking the potatoes in salt water before frying.

4.  Reverse osmosis - add energy to the system to force the water to flow backwards through a membrane.  It is used as a method to filter or desalinate water (but requires alot of energy)

5.  The different salt ratios in cells explain why salt water fish cannot go in fresh water and vice versa.

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chris-so-cool | Student, Undergraduate | (Level 1) Honors

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osmosis  is the phenomenon in which the two solutions of two different concentrations are separated by the semi permeable membrane. the molecules of the solvent move from their higher concentration to their lower concentration till the concentration of both the solutions becomes equal.

e.g: 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 of thistle funnel.

leave the apparatus undisturbed for 4-5 hours.

you 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 solutin. it it because of osmosis

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dannyjesusv | Student, Grade 9 | (Level 1) Salutatorian

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A good example of osmosis would be dipping a sponge into water, because there is a higher concentration outside, so the water goes in and makes the sponge expand.

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revolution | College Teacher | (Level 1) Valedictorian

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osmosis is a process which the movement of water molecules from a solution of higher water potential to a solution of lower water potential through a partially permeable membrane, and is present in animal or plant cells.

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interpreter | Student, Undergraduate | (Level 1) eNoter

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osmosis is the movement of solute from a higher concentration  to lower concentration through a semi permeable membrane.

eg. soak some dry grapes in water after 10 to 15 mins u can see them swell up. thisis due to the water.

thank you, i hope u find this usefull.

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rbrogdon | Elementary School Teacher | (Level 1) Honors

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Osmosis is the movement of something through a membrane from an area of greater concentration to an area of lesser concentration.

An example would be to place two tablespoons of raisins into one cup of water and let sit overnight. The next morning, observe the changes to the raisins. Take them out, keeping as much of the water in the cup as possible. Re-measure the water to see how much the raisins absorbed through osmosis.

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fami | Student, Grade 10 | (Level 1) Honors

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Osmosis is the movement of water molecules from a region of higher water potential i.e. a hypotonic solution to a region of lower water potential i.e a hypertonic solution, against the potential gradient, through a partially permeable membrane.

e.g:- The cellular system of animals/plants, which allows the water molecules and other dissolves substances to pass readily across the partially permeable cell surface membrane in or out from the cytoplasm of the cell. This accounts for

01. turgidity and plasmolysis in plants

02. crenation in animals


P.s:- don't confuse osmosis with diffusion for diffusion is the movement of fluid particles from a region of higher concentration to a region of lower concentration (not water potential) against the concentration gradient (not thepotential gradient). Unlike osmosis it is not an obligation to have a membrane. e.g:- evaporation

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rhales | Middle School Teacher | (Level 1) Honors

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Ways I have showed my students examples of osmosis:

Soak a gummy bear in water.

Soak a raw egg in vinegar to remove the shell. Then you can soak it in water and have the students measure the diameter of the egg. You can also soak it in other solvents and see how the diameter of the egg will change.

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i-am-urmi | Student, Grade 9 | (Level 1) Honors

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Osmosis is the movement of liquid molecules from a higher concentration to a lower concentration through a partially permeable membrane.

An example of osmosis can be the intake of water molecules in plants. As the cell sap of the root hair cell has a more concentrated solution than the soil, water particles moves in the cell through osmosis.

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go4knowledge2 | Student, Grade 11 | (Level 1) eNoter

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What is osmossis, it is the process of movement of solvvent from low concentration of soloute to high concentration of solute.

When you put rasins in water, after some time they swells. That is due to osmossis.

Thanks for asking.

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karan123- | Student, Grade 10 | (Level 1) eNoter

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a good eg.:-if u submerge some grapes in plain water(isotonic soln.),after some time the grapes swell up and may even burst

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absspace | Student | (Level 1) eNoter

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example of osmosis can be :

movement of water molecules form the mesophyll cells to the guard cells where the water gets transpired


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krishna-agrawala | College Teacher | (Level 3) Valedictorian

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Osmosis is a process in which liquid from one solution moves to another solution separated by a semi-permeable membrane. The most common examples of osmosis is provided by all plants and animals. Plant absorb water from the earth through the process of osmosis. Exchange of water in body fluids and body cells in animals (including humans) takes place through osmosis. Arabian countries with limitited supplu of drinking water use the proces of osmosis to generate drinking water from sea water.

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melissaivanarampersad | Student, Undergraduate | (Level 1) Salutatorian

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Examples of Osmosis Applied

The following are examples of osmosis for those of you who need to see an example to clearly understand science (like me)…

Example of osmosis 1.

If you put rice into a bowl of water, the water will move into the rice causing them to swell, while causing the water level to drop.

Osmosis example 2.

If a cell is placed in a container which is full of a hypotonic solution (not many solutes) than the fluid in that container will naturally want to be drawn into the cell and this will cause the cell to swell up and rupture (lyse).

Example of osmosis 3.

If a cell is placed in a container which is full of a hypertonic solution, than the cell will lose fluid as it is diffused outof the cell into the area of greater solute concentration. This will cause the cell to shrink (crenate).

Example of osmosis 4.

In medicine, if a patient drawns in salt water, the hypertonic water in the lungs will cause more fluid to be drawn out of the pulmonary arteries into the alvioli and lungs. This will more often result in pulmonary oedema than a patient who has drawned in fresh water.

Example of osmosis 5.

If you admister normal saline to a patient intraveneously (which has the same osmolarity as blood / the same amount of solutes as blood) it will mean that the fluid remains unchanged, because their is no osmotic gradient (basically all the fluid stays the same). Now, if you were to give mannitol (which is a very hypertonic solution) the fluid within the blood will be drawn out of the cells and into the mannitol solution.

Examples of Osmosis in Cells?

This becomes important when looking at the structure of cells in biology.

If a cell has a high concentration of a solute (salt) it will draw fluid into its cell. If allowed to continue to do this, it will eventually swell up and rupture (this is called cell lysis).

If a cell has a low concentration of a solute it will lose fluid as the fluid within its cell is allowed to be drawn out of the cell through osmosis and into the intersitial space. This will cause the cell to shrink (this is called cell crenation).

Practical Examples of Osmosis in Medicine

Basically, this concept becomes important when we start to administer hypertonic or hypotonic solutions. We understand that if we were to admister 100% sterile water intraveneously to patients who are dehydrated, the cells within the vasculature (blood vessels) would draw up all that fluid due to the osmotic gradient shift (this basically means that the fluid will want to shift into the cells) and this will cause the local cells to swell and lyse (rupture). This means that the red blood cells themselves will no longer be capable of carrying oxygen and serving their purpose.

Likewise, if you were to administer 50% glucose intravenously, the hypertonic solution (lots of solutes) will cause a lot of fluid to shift towards it. Now, so long as the canula is in a large vein, it will be able to draw fluid from a large area. However, if the canula is inserted in a small vein or accidentally inserted into the intersitial space and not a vein, it will not be able to draw fluid from all over, and consequently draw all the fluid from the surrounding cells. This will cause the cells to shrink (crenate) and again, become unable to sustain life. In these circumstance, patients may develop cellulitis or damaged veins.

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javaria95 | Student, Grade 10 | (Level 1) Honors

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when salt water is added to an elodea leaf and all the chloroplasts within the cell moves to the outside of the cell or to the center of the cell. It balances the water 

A red blood cell is placed in fresh water. There are more free water molecules outside the plasma membrane then inside the cell, so osmosis occurs- water diffuses through the blood cell (causing it to swell and burst). 
the movement of water from an area of lesser concentration to one of greater concentration
Also when you soak rice the starch from the rice goes into the water causing the change of color.

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