How cool is too cool? Well, how about -109.3 °F (-78.5 °C)? That's the temperature at which carbon dioxide (CO2) changes from a gas to a solid, and vice versa.
Though as a gas it's invisible, frozen CO2 – known as “dry ice” - looks a lot like water ice. Since the compound sublimes from a solid directly to a gas, however, dry ice is indeed dry to the touch.
Speaking of which, you don't want to actually touch dry ice as it can freeze flesh on contact and leave painful “burns”. All the more reason for staff at a certain Bubble Tea cafe in China to add cubes of dry ice to their drinks! Hey, the kiddies (and foreign tourists who should know better) just love it... check out this video:
Safety concerns aside, the dry ice cubes do add extra bubbles to any Bubble Tea, amiright? Not to mention the distinctive mad scientist effect of the thick, cold CO2 “smoke” exuded by the rapidly sublimating dry ice cubes inside each delicious cup. Everyone practice your Igor ("that's EYE-gor") impressions now!
You'll pay from 12 to 20 yuan ($2 to $3) for the pleasure of drinking dry ice infused Bubble Tea; and perhaps more later at the hospital depending on one's Blue Cross coverage. Cheers! (via Rocketnews24)