Why We Use Soap
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Why We Use Soap
How can soap help remove dirt?
homework question
After doing this experiment in class, my student asked me this: Why is it that when you soften your water (adding salt... right?) you still feel that the oil/soap is on your hands? any help?
Excellent question. The salt
Excellent question. The salt method of softening water is causing a chemical change, replacing the calcium and magnesium ions in the dissolved minerals with sodium ions from the salt. This reduces the "hardness" of the water, reducing scale buildup and soap scum, but since it is changing the chemicals instead of removing them, there are some disadvantages, such as the slippery feeling that it leaves on your skin.
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