page_title: Osmosis
hierarchical_section_title: Osmosis
caption_attribution_description: This is a shot from a three dimensional computer simulation of the process of en:osmosis. The blue en:mesh is impermeable to the larger balls, whereas all of the balls are (in the animated version) bouncing about according to the rules of physical simulation of the kinetics of an ideal gas. Averaged over long period of time, each ball has has the same kinetic energy as each of the other balls, even though at any given moment the velocities are distributed according to the appropriate en:Boltzmann functions. Likewise, each species (in this case color) of balls (as a group) exerts time averaged force (due to the bouncing) upon the walls of the box, which corresponds to the partial en:pressure contribution associated with that group. These properties emerge even though the collision function used in the simulation is trivial, to wit: void Mass::collide (Mass *X) { vector v_cm; v_cm = (velocity*mass+X-&gt;velocity*X-&gt;mass)/(mass+X-&gt;mass); velocity = v_cm*2 - velocity; X-&gt;velocity = v_cm*2 - X-&gt;velocity; m_bCollision = true; X-&gt;m_bCollision = true; } Accordingly, one can make theoretical assumtions about the behaviour of such mixtures according to the application of Dalton's law of partial pressures, and so on, and thereby gain some insights into how certain physical processes really work.
context_page_description: Osmosis is the movement of water through a semipermeable membrane from a region of high concentration to a region of low concentration, tending to equalise the concentrations of the water. Osmosis is passive transport, meaning it does not require energy to be applied. What causes osmotic pressure is different concentrations of solutes on the two sides of the membrane.
  When osmosis happens, water moves from the side of the membrane with a Higher amount of osmotic pressure to the side of the membrane with the lower amount. An important example of osmosis is the movement of liquid molecules across a cell membrane into a cell with a higher solute concentration. Osmosis is a fundamental part of cell biochemistry, but also has mechanical applications and usages.
context_section_description: Osmosis is the movement of water through a semipermeable membrane from a region of high concentration to a region of low concentration, tending to equalise the concentrations of the water. Osmosis is passive transport, meaning it does not require energy to be applied. What causes osmotic pressure is different concentrations of solutes on the two sides of the membrane.
  When osmosis happens, water moves from the side of the membrane with a Higher amount of osmotic pressure to the side of the membrane with the lower amount. An important example of osmosis is the movement of liquid (solvent) molecules across a cell membrane into a cell with a higher solute concentration. Osmosis is a fundamental part of cell biochemistry, but also has mechanical applications and usages.
caption: This is a shot from a three dimensional computer simulation of the process of osmosis. The blue mesh is impermeable to the larger balls, but the smaller balls can get through. All the balls are bouncing about
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