Here's a breakdown:

* Hypothesis: A proposed explanation for a phenomenon. It's a testable prediction that can be supported or refuted through scientific investigation.

* Forming a Hypothesis: Scientists use observations, prior research, and their own knowledge to formulate a testable hypothesis.

* Testing a Hypothesis: This is done through experiments, observations, or data analysis. The goal is to gather evidence that either supports or contradicts the hypothesis.

Example:

* Observation: Plants grow taller when they receive more sunlight.

* Hypothesis: Plants need sunlight to grow.

* Test: Set up two groups of plants: one in sunlight and one in the dark. Measure their growth over time.

Important Note: A hypothesis is not a guess; it's a well-reasoned prediction based on existing knowledge.