Bubble Bath

[kags]

Can someone please explain to me (in terms that would be understandable by a 9 year old), why bubble bath bubbles disappear when soap is added to the water. I have Googled this, and am none the wiser for reading the answers given.

[Skids]

Because of their different pH values.

[kags]

(anticipating the next question from the 9 year old) - but why would that make the bubbles disappear?

[-=BigD=-]

Because (in 9 yr old terms) bubbles like water and when saop is added it changes the water to saopy water which bubbles don't like so the bubbles disappear.

[MargeB]

Hi Kags.

All the air in the world pushed down on the bathwater. The bathwater pushes back up at the air. If you put soap in the water, it makes the bathwater push up a wee bit less. When it does this, it also makes it easier for bubbles to form on the water and hold together. If you slosh the water without soap, normally no bubbles appear. The soap in bubblebath is good at making this happen.

The problem comes with bars of soap. I think normally would be good at making lots of bubbles, but when they are put in water they release a special ingredient (calcium I think) and it makes bubble making harder.  This is because people used to complain about all the soapy suds from baths clogging up rivers and upsetting the ducks.

Paul

[kags]

Thank you MargeB, I can understand that, and my 9 year old is much smarter than me so I am sure he will understand too! Thanks also to BigD and Skids.