Today in class we went over the concept of osmosis and diffusion. Osmosis is when water travels through a semi-permeable membrane from areas of higher concentration, to areas of lower concentration. Diffusion is kind of like the same thing but is not specific to water. It deals with a solutes concentration gradient, and how the solution travels from areas of higher concentration, to areas of lower concentration. After reviewing these concepts, we went into more detail and talked about what makes something hypertonic, hypotonic, and isotonic. A hypertonic solution that has
higher osmotic pressure (or has more solutes) than another solution to which it is compared. A hypotonic solution refers to any solution which has a
lower osmotic pressure than another solution (that is, has a lower concentration of solutes than another solution). Isotonic solutions are two solutions that have the
same concentration of a solute. here are some notes from class:
After this we set up three experiments to help with our understanding of osmosis.
The first experiment required us to fill tubing to with solutions that that had varied amounts of solute in it. We would then place this tubing into a cup of pure water and measure its mass after fifteen minutes or so. Here are some pictures of the first experiment:
The second experiment was where we cut up potatoes and placed them in covered cups of the different solutions. We would then come in later that day to record any changes in mass. here are is a picture:
The third experiment required us to fill tubing with a sports drink (we chose vitamin water) and place it in a covered cup filled with the different solutions. Once again we would later come back to see if there were any changes in mass. More pictures:
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