Reverse Osmosis

[hazelm]

When the label on a bottle of lens cleaner says the ingredient is "reverse osmosis water, isn't it giving us just plain water?

 

Actually not giving anything since no amount of pushing on the plunger brings out anything.  But the label does say "reverse osmosis water".  Given to me by the optometrist's office with my new glasses.

 

Thanks

[exchemist]

When the label on a bottle of lens cleaner says the ingredient is "reverse osmosis water, isn't it giving us just plain water?

 

Actually not giving anything since no amount of pushing on the plunger brings out anything.  But the label does say "reverse osmosis water".  Given to me by the optometrist's office with my new glasses.

 

Thanks

it  means water purified by reverse osmosis, an alternative to distillation.

 

The water is made to pass through a semi-permeable membrane, under an applied pressure to overcome the osmotic pressure that would normally make the water tend to flow from the purified side to the impure side. 

[hazelm]

it  means water purified by reverse osmosis, an alternative to distillation.

 

The water is made to pass through a semi-permeable membrane, under an applied pressure to overcome the osmotic pressure that would normally make the water tend to flow from the purified side to the impure side. 

Oh!  All right.  Thank you.  I should have "googled" or "wiki'd" it before opening my mouth.  Thank you.

[exchemist]

Oh!  All right.  Thank you.  I should have "googled" or "wiki'd" it before opening my mouth.  Thank you.

Osmosis is one of a number of phenomena that go by the name of "colligative properties". More here: https://en.wikipedia.org/wiki/Colligative_properties 

 

- in case you have trouble sleeping at night....

 

If you have 2 solutions separated by a semi-permeable membrane, so that water molecules can get through it but not those of the substance dissolved, water tends to diffuse from a weaker solution into a stronger solution, i.e. in the direction needed to even out the two concentrations.

 

The water will continue diffusing from the weaker side to the stronger side until the level of liquid on the stronger side has risen enough to exert a pressure that counterbalances the tendency to diffuse. This is known as the "osmotic pressure". 

 

In reverse osmosis, you exert a pressure, artificially, on the side with the stronger solution, to force water back through into the weaker solution, against this natural osmotic pressure. It's a kind of molecular level filtration, basically. 

 

Osmotic pressure is an important concept in biology. It accounts for how a lot of cellular behaviour works - and even why you find "burst" earthworms on your lawn after rain!  

[hazelm]

Osmosis is one of a number of phenomena that go by the name of "colligative properties". More here: https://en.wikipedia.org/wiki/Colligative_properties 

 

- in case you have trouble sleeping at night....

 

If you have 2 solutions separated by a semi-permeable membrane, so that water molecules can get through it but not those of the substance dissolved, water tends to diffuse from a weaker solution into a stronger solution, i.e. in the direction needed to even out the two concentrations.

 

The water will continue diffusing from the weaker side to the stronger side until the level of liquid on the stronger side has risen enough to exert a pressure that counterbalances the tendency to diffuse. This is known as the "osmotic pressure". 

 

In reverse osmosis, you exert a pressure, artificially, on the side with the stronger solution, to force water back through into the weaker solution, against this natural osmotic pressure. It's a kind of molecular level filtration, basically. 

 

Osmotic pressure is an important concept in biology. It accounts for how a lot of cellular behaviour works - and even why you find "burst" earthworms on your lawn after rain!  

Well, they must have reversed the lens cleaner solution once too often as, no matter how much I pushed the plunger on that bottle, no  water ever came out.  It was in there.  I could see it.  But I got nothing.  I checked Wiki.  They even do it for washing windows.  I am guessing it is to prevent scratches on the glass.  Would I be right?

 

Those poor worms.  I thought they dehydrated from sun exposure.  When I lived where I had a patio which didn't quite touch the building,  I would get swarms of earthworms up from under the concrete and onto the patio where they enjoyed their bath.  When rain began letting up, most swarmed back down fast as they could go.  A few hung back too long.  Sounds like children? :-)