Uncertainty is the state of not knowing what will happen or not being sure about something. When you feel uncertain about whether it will rain tomorrow, you don't have enough information to predict the weather confidently. When a scientist faces uncertainty in an experiment, the results could go several different ways.

Uncertainty is different from simply not knowing a fact you could look up. It's about situations where the answer isn't available yet because events haven't unfolded or because the information is incomplete. A student might feel uncertain about which project topic to choose, or about whether they'll make the soccer team. An explorer in the 1400s faced tremendous uncertainty about what lay across the ocean.

Some people handle uncertainty better than others. While uncertainty can feel uncomfortable, it's also a natural part of life. Scientists work with uncertainty all the time, designing experiments to reduce it. Entrepreneurs face uncertainty when starting businesses, not knowing if their ideas will succeed. Sometimes you have to make thoughtful choices and move forward even when you can't be completely sure how things will turn out.