Actually, when you touch an ice cube with your finger or your tongue, the coldness of the ice immediately freezes the moisture on your tongue and finger too and it then sticks to you. Or, (with regard to a finger) the heat from the finger may suddenly melt a little bit of ice but then the ice cube fights back and freezes the water and sticks.
In any case, it's because the finger/tongue has stuck due to moisture freezing on contact!
2. Is sports drinks acidic?
Yes. Some sports drinks even has a pH level as low as 3.07. Examples of sports drinks such as Vitamin Water, Life Water, Gatorade and Powerade have been proved that they are able to damage tooth enamel, even more so than soda due to a combination of acidic components, sugars, and additives.
3. Glycerin Experiment
Just some information, Glycerin is neutral, sweet-tasting, colorless, thick liquid which freezes to a gummy paste and which has a high boiling point. Glycerin able to be be dissolved into water or alcohol, but not oils. On the other hand, many things will dissolve into glycerin easier than they do into water or alcohol. Thus it is a good solvent.
The big beaker is filled with glycerin, making the small beaker look invisible. Because glycerin has the same index of refraction as the pyrex glass in the beaker, light goes through the beaker, instead of bouncing off and hitting our eyes. As a result, the small beaker seems invisible.
By the way, I also came upon this interesting video from Youtube. Enjoy! =)
