When you stir sugar into water, the crystals will swirl and eventually disappear, but the molecules aren't gone -- they've just dissolved. Take a sip and the water will taste sweet. In order to separate the sugar from the water, you'll have to do an evaporation experiment.
A Sweet Experiment
Evaporation is the process through which matter changes from a liquid to a gas. In a sugar-water solution, water will evaporate and leave behind the sugar. You can do a simple evaporation experiment with kitchen utensils. Stir several spoonfuls of sugar into a glass of hot water. Knot a piece of yarn around the middle of a pencil. Place the pencil on top of the glass so that the string is dangling into the solution. Leave the glass somewhere safe until all the water evaporates. You'll see sugar crystals clumped onto the string and the bottom of the glass.