What is an example of osmosis?

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Examples of osmosis—the equalizing movement of molecules through a semipermeable barrier—can be found in desalination, water treatment, and food preparation.

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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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Osmosis is defined as the movement of solvent molecules through a semi-permeable membrane.  The solvent molecules (often water) will naturally move through the membrane from areas of high concentration to areas of low concentration.  This has the effect of equalizing the concentrations of two different solutions separated by a semi-permeable membrane.  This type of membrane allows the water molecules to pass freely through it but the solute molecules (the substances dissolved in the water) cannot pass through and as such are trapped on their respective sides of the membrane.

An example of osmosis is putting a slice of tomato into a solution of saltwater.  The fiber of the tomato acts as a semi-permeable membrane allowing the water to pass through.  The saltwater has a lower concentration of water due to the presence of the salt molecules compared to the water inside of the tomato slice.  As a result, the water will transport out of the tomato slice over time and into the surrounding saltwater solution, thus making the tomato slice shrivel up and become smaller.

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What is an example of diffusion-osmosis?

Diffusion is an equalling of the concentration of particles within a given unit of space.  A good example of diffusion would be if I strike a match in one corner of the room, in just a few minutes, the odor of sulfur from the burning match would spread throughout all the air molecules within the room.

Osmosis is a form of diffusion, except through water concentration within an object.  It is a process which equallizes the water content in an organism or unit by passing water across a semi-permeable membrane, which means the membrane will allow some things to pass through, but not all things.  A good example I used in my class room this year to demonstrate osmosis was to take an egg and soak it in vinegar for 24 hours to remove the calcium from the egg shell.  The next day, I took the now pliable egg and immersed it in table syrup, which has a low concentration of water, for another 24 hours.  The next day, I removed the egg, which was now "deflated" because some of the water content within the egg diffused across the membrane into the syrup, in an attempt to equalize the water concentration.  I then took the "delated" egg and soaked it another 24 hours in water; the next day, it was back to it's original inflated self, as the water diffused back into the egg.

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Example of osmosis?

Osmosis is the diffusion of water through the cell membrane. The cell membrane is selectively permeable and water is able to pass through it.  If there is a higher concentration of water, outside the cell membrane, relative to the inside, inward osmosis will occur. The contents of the cell will swell. This can be seen under a compound microscope using onion cells. If a wet-mount slide of onion epidermis is prepared and the cells are placed in distilled water, the cytoplasm of the cell will expand due to inward osmosis. There will be a greater concentration of water outside the cell, relative to the inside and inward osmosis will occur. In microscopic organisms living in freshwater, there will always be inward osmosis occurring and the homeostasis of these cells would be threatened because they could potentially burst. However, mechanisms like contractile vacuoles use energy to push out the excess water from these cells.

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