Whereas plastic is relatively
strong, may be made optically transparent, is inexpensive
and lightweight, and is recyclable, it is not
as impervious to the passage of carbon dioxide as
aluminum and glass. For example, you may have noticed
that beverages in aluminum and glass containers
retain their carbonization (i.e., “fizz”) for several
years, whereas those in two-liter plastic bottles “go
flat” within a few months