We had two labs in class the other day. The first was a lab where we created a "cell" with glucose and starch in the mixture, then soaked in water (in a beaker) for some time. After soaking it in water, we took out 1 mL of the water in the beaker, put a dropper full of benedict solution in, and put it into a test tube, which we them proceeded to dip into hot water for a few minutes. The water in the test tube turned a murky orange color, like this:
Then, we put a few drops of iodine into the beaker, and waited for another few minutes. The cell turned into a bluish black color, since the iodine went into the cell because of diffusion. The iodine reacted with the starch and glucose, which is why the cell's contents changed color. It looked like this at the end:
The second lab was a lab that also had to do with diffusion. We had pieces of NaOH that were cut into cubes and prisms, and we dropped them into beakers filled with phenolphthalein. The solution immediately turned pink, and we left the pieces of NaOH in the solution for around 3 minutes. Afterwards, we took them out and cut them in half. The pink color had soaked through about 1 millimeter all around, and the rest was still white. (It's not very clear in the picture, but that's definitely what happened.)
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