Spine Fit

This is another question that I’m going to clear. Most of us notice that after a couple of times a new soap doesn't produce the same amount of lather it once used to. Many of the people who hardly have a bath or the ones who have found an alternative, wouldn't understand what I’m talking about, but for the rest of the normal people I’m going to give a lucid, logical reason why this happens.

When soap is made it consists of a homogenous mixture of lather forming agent with similar characteristics to a detergent and a fatty acid based constituent. When water is used to lather up the detergent in the soap mixes with the soap and forms lather. This effectively reduces the surface tension of the water and results in better lather formation. However when there are lots of dissolved salts in the water, which is typical of a type of water called hard water, the detergent interacts with these salts and prevents the formation of lather. This can be prevented by using alum or other agents that effectively sediment the salts thereby reducing the salt content in the water. However, what happens over time in order to reduce the lather in soap is quite different. The prolonged exposure to water causes all the detergents in the soap to diffuse towards the outer layer of the soap where it can interact with the water present. This continuous movement of the soap reduces the homogeneity in the bar of soap and these results in the decrease in the amount of detergents in the inner regions of the soap. The ultimate effect of this phenomenon is that the inner regions of the soap do not form as much lather as the outer regions do.