Answer:
Skittles are coated with sugar and food coloring. When you add warm water to the Skittles, the sugar and food coloring start to dissolve. They have similar amounts coated on them so they dissolve at similar speeds and stay in their lanes.
The sugar is moving to areas of water with lower sugar concentration. If the water is poured in the center, this is happening for each Skittle at relatively the same speed.
Step-by-step explanation: