This mystery can be used to introduce osmosis and diffusion.
Two beakers are displayed at the front of the room. Both look identical in that they both contain a plastic zip--lock bag with a starch solution inside. The zip-lock bags are both sitting in a clear solution. What the students don’t know is that while the solution in one beaker is just water, the second also contains iodine. In beaker two, the colour of the solution inside the zip-lock bag will change. Students need to figure out why this is happening.
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