ELI5 Dry Ice - why should it never go in a swimming pool?

How is dry ice made? Why does metal make a 'screaming sound' when dry ice is touched to it? Is it possible to make fizzy fruit with it? Why should we never put dry ice into a swimming pool?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: utahraptorIseternal, extralargelobes, multifazed, haort, hellowmanderdoo, firedan1176, em2skinner & concise_pirate For some cool science experiments to do with dry ice, check out this site: https://dryiceinfo.com/science.htm To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]