2007-03-25 15:07:50 · 8 answers · asked by kmsram420 1 in Science & Mathematics ➔ Other - Science
Most have the right idea, but let me clarify. Most oils and fats are not soluble in water. Rinsing your hair with water may remove loose dust and dirt but not the oils. Soap, detergent, surfactants, and related chemicals help dissolve the oil. See the first reference for how surfactants do it. During your first washing, most of the surfactant is consumed in the process of dissolving the oils. During subsequent washings, there's less oil to dissolve, so the surfactants can do the other thing they do well: facilitate soap bubbles.
To reduce pollution, manufacturers have developed surfactants which produce little or no foam. But they often add foaming agents so naive consumers can tell when the stuff is working. Some people won't believe their hair or their laundry is clean unless they see suds. To get the best, most environmentally responsible cleaning with today's products, use just enough to leave some foam residue, but no more.
2007-03-25 18:45:46 · answer #1 · answered by Frank N 7 · 0⤊ 0⤋
The first time bonds the oil in the hair which kills the foam, and the second time there is no oil in the hair to kill the foam.
2007-03-25 15:11:45 · answer #2 · answered by justbeingher 7 · 0⤊ 0⤋
The first time the detergent in the shampoo react (like it should) to the oils in your hair. The second time there is less oil thus more suds. If you want to save money, use less shampoo on the second time around. We overuse most of our hygiene products but the manufacturers love that.
2007-03-25 15:14:20 · answer #3 · answered by RickinAlaska 4 · 0⤊ 0⤋
The first time you're removing oils from your hair; it's still cleaning but the oil retards the foaming.
The second time the hair is cleaner.
2007-03-25 15:10:54 · answer #4 · answered by Anonymous · 3⤊ 0⤋
Because the first time there are oils and any remains of products still in your hair. The second time it is cleaner and therefore more foam
2007-03-25 15:11:33 · answer #5 · answered by calired67 4 · 0⤊ 0⤋
The first time around, the shampoo combines with the oil and grease on your hair, leaving little to make suds. The second time, most of the oil is gone, so more suds.
2007-03-25 15:20:14 · answer #6 · answered by Anonymous · 0⤊ 0⤋
1st time-lots of oil in your hair that made les foam.
2nd time-cleaner hair so more foam.
ta da!
2007-03-25 15:17:28 · answer #7 · answered by sara 2 · 0⤊ 0⤋
We have the same problem. It's called hard water. Lots of iron and minerals in
it.
2007-03-25 15:10:51 · answer #8 · answered by Garnet 6 · 0⤊ 2⤋