Re: What makes sugar sticky?

Sugar itself has many forms. I assume that you mean normal table sugar. This sugar is not sticky when it is dry, but when it gets wet it becomes sticky due to something called hydrogen bonding. The formula for sugar is C6H12O6. When this interacts with water the hydrogens in the sugar and the hydrogens in the water have an attraction toward each other. It is these hydrogen bonds which make the sugar "sticky". There are many ways which sugar can pick up moisture. These include, but are not limited to moisture from your hands and the atmosphere. A very concentrated solution of sugar can also be sticky. If you get just a small amount of water in a pile of sugar you have made a sugar solution which is saturated and has a very high concentration of solids. A good, non-sticky example to use is sand at the beach. When it is dry, it flows freely. If you add just a little water, the sand will clump together, although it still looks like sand, much the way sugar reacts to water. One thing to remember is that sugar will dissole in water, but sand will not.