If you're looking for a fun (but dangerous – wear gloves and eye protection!!) science experiment to do at home, here's a good one. Simply stir drain cleaner (98% sulfuric acid) into some sugar, and watch as it turns into a black monstrous blob that pushes its way out of the glass.
The science behind it? From ThoughtCo:
The sulfuric acid removes water from the sugar in a highly exothermic reaction, releasing heat, steam, and sulfur oxide fumes. Aside from the sulfurous odor, the reaction smells a lot like caramel. The white sugar turns into a black carbonized tube that pushes itself out of the beaker.
Sugar is a carbohydrate, so when you remove the water from the molecule, you're basically left with elemental carbon. The dehydration reaction is a type of elimination reaction.
C12H22O11 (sugar) + H2SO4 (sulfuric acid) → 12 C (carbon) + 11 H2O (water) + mixture water and acid
Although the sugar is dehydrated, the water isn't 'lost' in the reaction. Some of it remains as a liquid in the acid. Since the reaction is exothermic, much of the water is boiled off as steam.