A Little Bit More
Every living organism must maintain a balance of water in its body for life to exist. If an organism can’t maintain this balance, all kinds of problems can arise that can lead to death. Most of us have learned about osmosis in school and know that this physical movement of water is a very important part of life on earth.
According to one biology textbook, osmosis is “the movement of water through a membrane down a water potential gradient”. It also can be said that osmosis is the ability of a non-pure water solution to gain water when separated from pure water by a semi-permeable membrane.
I’ve always had trouble remembering which way the water would travel in a given situation and find it easier to think of this process with a concrete example in mind. If an object that is NOT pure water is placed in contact with PURE water I can figure out what must take place to equalize, or attempt to equalize, this arrangement. IF water from the NOT-pure water system leaves and goes through a membrane to the pure water, the NOT-PURE side simple becomes more and more concentrated and does not approach equilibrium. If, however, water from the PURE-WATER side goes through a membrane into the NOT-PURE side, it will move the two solutions closer and closer together towards equilibrium. I hope this helps the next time you need to figure out which way the water moves!
Activities
Science – Osmosis
Objectives: See osmosis in action
Materials: Online access
There are lots of ways you can show osmosis in action so I’m sharing a few websites that will do just that. Check these out and choose what you feel will address the needs of your students in the best way.
Activities on Osmosis – grade 5-8
Simple osmosis activity
Osmosis activity
Key Concepts
Adaptations and Diversity, Behavior and Regulation, Environmental Issues, Structures and Functions
Questions
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