What is Osmosis?
Unfortunately osmosis is where the concept of diffusion gets even more confusing. Rather than the simple process of one chemical evening itself out, osmosis relates to a situation where something is dissolved in something else. It is initially rather important that you understand the difference between a solvent and a solute – a solute being the thing which is dissolved, and the solvent being the thing which it is dissolved in. If you make a cup of tea and decide to have some sugar in it, then the drink of tea is the solvent because you are dissolving into the tea, and the sugar is the solute, because it is dissolving into it. The definition of osmosis is very difficult to understand, but once it is explained, it makes a lot more sense. Put very simply, osmosis – when refering to water – is effectively the diffusion of water molecules. The strict definition is the diffusion of a solvent, through a partially permeable membrane, from an area of low concentration to an area of high concen
Osmosis is a process in which a fluid passes through a semipermeable membrane, moving from an area in which a solute such as salt is present in low concentrations to an area in which the solute is present in high concentrations. The end result of osmosis, barring external factors, will be equal amounts of fluid on either side of the barrier, creating a state which is known as “isotonic.” The fluid most commonly used in demonstrations of osmosis is water, and osmosis with a wide variety of fluid solutions is key for every living organism on Earth, from humans to plants. There are some key terms related to osmosis which may be helpful to know when thinking about how osmosis works. The fluid which passes through the membrane is known as a solvent, while the dissolved substance in the fluid is a solute. Together, the solvent and dissolved solute make up a solution. When a solution has low levels of a solute, it is considered to be hypotonic, while solutions with high solute levels are know
Osmosis quite simply is the physical process by which a liquid from a weaker medium is drawn through a semi-permeable membrane into a stronger liquid medium. So what does this mean and how does this relate to boat hull damage? The simple answer is probably not a lot! Contradicting earlier theories, the damage from “osmosis” is not caused by excessive water permeation. There are absolutely no osmotic forces involved as the gelcoat is an absorbing material which can never act as an osmotic membrane! Instead it is the process of hydrolysis, which creates the water soluble corrosive products which in turn create the familiar cavities. (Hydrolysis is the general term given to the reaction of any material with water, for example organic compounds like polyester resin, itself the main constituent of GRP laminates.) Once the cavities have formed, then excess water will enter giving rise to high moisture readings. This process may normally be slow, but the presence of free acids or alkalis will
This is called osmosis, the reason it is important is that all living cells are covered with these materials which will let water through but not salt or sugars ( they are called partially permiable membranes by the way) so if you stay in a bath too long water moves into your skin and your fingers go all wrinkley, if you go swimming in the sea and get covered with salt, you get really thirsty as the water is sucked out of you by the salt and osmosis, and for the same reason snails shrivel up when you pour salt on them…. oh and it drives lots of important biological processes.
Osmosis is based upon the fundamental pursuit for balance. Two fluids containing different concentrations of dissolved solids that come in contact with each other will mix until the concentration is uniform. When these two fluids are separated by a semi permeable membrane (which lets the fluid flow through, while dissolved solids stay behind), the fluid containing the lower concentration will move through the membrane into the fluid containing the higher concentration of dissolved solids (Binnie e.a., 2002). After a while the water level will be higher on one side of the membrane. The difference in height is called the osmotic pressure. What is Reverse Osmosis? By applying a pressure that exceeds the osmotic pressure, the reverse effect occurs. Fluids are pressed back through the membrane, while dissolved solids stay behind. To purify water by Reverse Osmosis membrane, the natural osmosis effect must be reversed. In order to force the water of the brine stream (high salt concentration)