What is Osmosis? Osmosis is the movement of water through a semi-permeable membrane. During osmosis, the water moves from an area of low-concentration (i.e. a little bit of solute) to an area of high-concentration (i.e. a lot of solute).
Osmosis is often confused with Diffusion, which is the movement of particles instead of water. One of the most confusing things is that these two processes frequently happen simultaneously, such as when the kidney’s are filtering blood.
In reality, Diffusion and Osmosis are both essential processes in the body that are used to counterbalance each other and maintain homeostasis.
Watch this cool experiment that you could even do at home yourself to help explain Osmosis.(Yes…I accidentally broke an egg while recording. This is real life, folks!)
So what’s happening in the Osmosis video? First, I dissolved egg shells in vinegar, which was way fun and worth doing once even if you don’t plan on trying the rest of the experiment. Squishy raw eggs are just cool.
With the eggshell out of the way, the thin semi-permeable membrane just underneath the shell is left intact. I’ve seen some people who can successfully bounce the egg once the shell is dissolved…obviously, you can see in the video that bouncing did NOT work so well for me 🙂
Then I placed each egg in a different solution: water (hypotonic), saline (isotonic), corn syrup (hypertonic). Then I waited…and showed the results in my video!
As you can see, although the difference between the eggs in the hypotonic and isotonic solutions are not huge, there IS a slight size difference. The hypertonic solution, on the other hand, had VERY clear results!!
Looking back, I think the less than stellar results I got for the isotonic/hypotonic comparison was due mostly to the vinegar. It looks like vinegar is a hypotonic solution, which means that since I left my eggs in the vinegar solution for a couple extra days after the shells dissolved, then they probably absorbed extra water from vinegar before I even started the experiment. I had noticed that they seemed bigger than when I had first put them in the vinegar, but didn’t think anything of it at the time. Now I know that was probably a problem!
I don’t do these experiments solely for my own enjoyment (although it was kind of fun). So let’s apply it to nursing now. Think about how the the different IV solutions we use affect the body. What if that egg was actually a red blood cell? What would happen to a patient who got too much hypertonic IV solution? Not a great situation!
Osmosis is a real phenomenon that has real consequences in our nursing practice, so it’s important to make sure you really understand what’s going on at the molecular level. I’m working on a series of articles that go into a little more detail on what happens for patients when they get different types of IV fluids, so be on the look-out for those soon.
If you liked this experiment, make sure to leave a comment below and let me know! Got any questions about osmosis or about how I did this experiment? Ask those in the comments below, too!