I found this link on the snopes website and thought it was very interesting. They said that there is not a special substance in pools that turns urine a different color. To prove this, they used scientific thinking. First, they had to rule out rival hypothesis. To do this, they would have had to have gone out and found a chemical that turned a different color when exposed to just urine. These chemicals tend to react to many other substances found in urine that can be found in everyday life. Second, they would have had to have been able to disprove this. Thus, they would have had to have found a chemical that does react to urine alone. Third, this experiment would have had to have been able to be replicated. They would have to be able to perform it twice. There has been no such chemical that has been found to change colors when exposed to urine. Many people have believed in this myth for some time because they believe that kids would be less likely to urinate in a pool if they knew that it would change colors.
Laurel Swendsen firstname.lastname@example.org