Separate glasses using physics
When you see two glasses stuck together, you usually try separating them yourself, but that can end very badly since it rarely works out. The glass might break in your bare hands, and you could get hurt. You better use physics to separate them while you enjoy the show.
When physics and grandparents intertwine, we can learn many things, and separating glasses is one. Fill the top glass with cold water and put the lower one inside a bowl with warm water. The opposite temperatures will collide, causing both glasses to separate easily without you risking getting cuts all over your hands.