I rather liked the analogy of the soda siphon and the cylinders.
Carbonated water is made using a soda siphon or a home carbonation system or by dropping dry ice into water.
Home soda siphons and soda water are enjoying a renaissance in the 21st century as retro items become fashionable.
Contemporary soda siphons are commonly made of aluminum, although glass and stainless steel siphons are available.
