# Soap and the death of a bubble bath
**URL:** https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575
**Category:** Factual Questions
**Created:** [June 10, 2004, 1:28am UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575 "2004-06-10T01:28:58Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Antigen](https://boards.straightdope.com/u/Antigen)
#### Post date: [June 10, 2004, 1:28am UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/1 "2004-06-10T01:28:58Z")
Why do the bubbles all disappear in my bubble bath after I lather up with a bar of soap?
Bubble bath = liquid soap, so why would the addition of more soap ruin my bubbles?
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### Author:  [@antechinus](https://boards.straightdope.com/u/antechinus)
#### Post date: [June 10, 2004, 2:28am UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/2 "2004-06-10T02:28:41Z")
This is similar to a recent thread about the foaming power of various detergents.
Bubble bath has detergents that are high foaming. The bubble films are made up of a layer of detergent molecules all the same size on either side of a thin film of water. The molecules have a water-loving head and water-hating tail so they all end up pointing in the same direction to form either side of the film.
When you introduce different types of detergents, such as soap, then there are molecules are a slightly sifferent size and shape that want to get into the film. The ordered layers of detergent moleculaes are disrupted by the other detergent and the bubbles cannot form as easily.
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### Author:  [@RobertG](https://boards.straightdope.com/u/RobertG)
#### Post date: [August 4, 2014, 1:51pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/3 "2014-08-04T13:51:39Z")
Soap (meaning actual soap soap) reacts with so-called “hardness” minerals (mostly calcium, then magnesium, then a few less prevalent) in water to form lime soaps, which are anti-foams. No defoaming effect of soap is seen in a bubble bath in water that has been completely “softened”. Some laundry detergents have used small amounts of soap as an anti-foam.
Anti-foams work by collecting at the same surfaces of water that make up bubble films, and breaking the structure of the film-forming molecules – not the individual molecules, but the structure they form together at the surface.
Meanwhile the bubble bath prevents the lime soap from aggregating on surfaces as bathtub ring or scum, which it would do otherwise. So you get 2 benefits: The soap in “hard” water breaks the foam to make draining the tub easier, and the bubble bath keeps the soap you’re using to wash with from leaving a ring. You just have to time it so you’re bored with the bubbles before you start washing.
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### Author:  [@Poysyn](https://boards.straightdope.com/u/Poysyn)
#### Post date: [August 4, 2014, 2:18pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/4 "2014-08-04T14:18:43Z")
Try a Lush bubble bar, those things last and last!
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### Author:  [@johnpost](https://boards.straightdope.com/u/johnpost)
#### Post date: [August 4, 2014, 2:39pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/5 "2014-08-04T14:39:53Z")
zombie or no
if it’s good stuff the bubbles come back.
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### Author:  [@DingoelGringo](https://boards.straightdope.com/u/DingoelGringo)
#### Post date: [August 4, 2014, 2:42pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/6 "2014-08-04T14:42:21Z")
> [@Antigen](#):
>
> Why do the bubbles all disappear in my bubble bath after I lather up with a bar of soap?
>
> Bubble bath = liquid soap, so why would the addition of more soap ruin my bubbles?
I’m available to wash your back, bubbles or not.
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### Author:  [@jayjay](https://boards.straightdope.com/u/jayjay)
#### Post date: [August 4, 2014, 11:54pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/7 "2014-08-04T23:54:02Z")
> [@DingoelGringo](#):
>
> I’m available to wash your back, bubbles or not.
THAT wasn’t creepy at all…
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### Author:  [@Channing\_Idaho\_Banks](https://boards.straightdope.com/u/Channing_Idaho_Banks)
#### Post date: [April 22, 2015, 6:22pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/8 "2015-04-22T18:22:58Z")
I’m pretty sure this has to do with phosphorous levels in soap that cause bubbles. That has been banned for years to try to keep waterways from turning into a foamy mess.
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### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [April 22, 2015, 6:48pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/9 "2015-04-22T18:48:30Z")
> [@RobertG](#):
>
> Soap (meaning actual soap soap) reacts with so-called “hardness” minerals (mostly calcium, then magnesium, then a few less prevalent) in water to form lime soaps, which are anti-foams.
Calcium and magnesium stearate, if I’m not mistaken.
Anyway, this is the explanation that makes the most sense to me; there’s not any appreciable amount of phosphorus in soap or bubble bath, and using other detergent type products (body wash, shampoo) containing a mix of synthetic detergents (primarily sodium laureth sulfate, decyl glucoside and cocamidopropyl betaine) won’t de-bubble a bubble bath, while soap manages it in a matter of a minute or two.
I have a small boy and a baby; I’ve learned how to avoid the de-bubbling!
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [April 22, 2015, 6:58pm UTC](https://boards.straightdope.com/t/soap-and-the-death-of-a-bubble-bath/249575/10 "2015-04-22T18:58:11Z")
> [@Channing\_Idaho\_Banks](#):
>
> I’m pretty sure this has to do with phosphorous levels in soap that cause bubbles. That has been banned for years to try to keep waterways from turning into a foamy mess.
Phosphorus in detergents is banned because it stimulates algae growth, which then leads to oxygen depletion and “dead zones.”
> **[Dead zone (ecology)](https://en.wikipedia.org/wiki/Dead_zone_(ecology))**
>
> Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen (DO) concentration falls to or below 2 ml of O2/liter. When a body of water experiences hypoxic conditions, aquatic flora and fauna begin to change behavior in order to reach sections of water with higher oxygen levels. Once DO declines below 0.5 ml O2/liter in a body of water, mass mortality occurs. With such a low concentration of DO, these bodies of water fail to support the