Examples of osmosis of salt
Answers
BY DIPAKJ
This is by far the most popular example of osmosis, probably appearing in every chemistry textbook in the country. As you will see with many examples of osmosis, this animal cell example involves salt and water. Our cells have semipermeable membranes that do not allow salt particles to flow in and out. The only way, then, “water down” an over salted cell is to allow water to move back and forth. Therefore when we are dehydrated and drink a lot of water, we are reaching equilibrium in our cells by filling them back up with water.
Water Soak
You can soak a large number of things in water to literally watch osmosis take place before your eyes. Dehydrated fruits and vegetables are great examples. The water isn’t simply flowing into empty spaces inside the fruit. It is literally passing through the cell walls and re-hydrating the fruit or vegetable. Something such as a raisin will have a very, very high concentration of sugars and water (do not confuse concentration with quantity; the raisin has little water, but it is highly concentrated). Thus, the water flows from a point of low concentration (the cup or bowl of water) to one of high concentration (the raisin). In this way equilibrium is achieved.
3. Root Pressure
I mentioned animal cells above, but plant cells work in the same fashion and are just as popular for osmosis examples. If you’ve ever wondered how roots generate “pressure” to withdraw water and nutrients from the soil, it’s through osmosis. This is accomplished by attracting the polar nutrients in the soil toward the root’s cells. It’s a very clever trick because the nutrients bring water with them and therefore solve this necessary problem for plants.
4. Cholera
Osmosis allows for terrible things to happen, as well. Cholera would not be possible without osmosis. The choleric bacteria populate in our intestines and begin to reverse the intestinal cells’ ionic orientation. In other words, it changes the way ions and, subsequently, water are transported in our intestines. So what does this mean, exactly?
It means that the cholera perform a perfect coup. First of all, when our ions’ orientations are switched, the intestinal cells are no longer able to absorb water into the body. Just the opposite, in fact. Now osmosis happens in the other direction and water moves from our intestinal cells into our intestines. This is what causes cholera’s infamously deadly watery diarrhea. Second, this compounds the rate at which you get dehydrated. Not only can you not absorb water, you are literally being drained dry. This is why cholera can kill you so quickly, because it does not rely on how much water you consume.