Here's why:

* Simple carbohydrates are made up of short chains of sugar molecules. These molecules are polar, meaning they have a slightly positive and slightly negative end.

* Water is also a polar molecule.

* Polar molecules attract each other, which is why simple carbohydrates dissolve in water. The water molecules surround the sugar molecules and pull them apart, allowing them to dissolve.

Examples of simple carbohydrates that dissolve in water:

* Glucose

* Fructose

* Sucrose (table sugar)

* Lactose (milk sugar)

Note: While most simple carbohydrates dissolve readily in water, there are some exceptions. For example, some complex carbohydrates, like starch, can form suspensions in water rather than dissolving completely.