The Heisenberg Uncertainty Principle is much like trying to observe a single drop of rain in a storm while running. If you try to determine exactly where the drop is, you'll have a hard time determining its speed. But if you try to determine its speed, you'll have a hard time pinpointing where exactly it is. Despite having all the awareness, you can't simultaneously measure both with perfect accuracy. Like the raindrop, either the position or the velocity of a subatomic particle can be measured accurately at any given instance, but not both.