Which concept is defined as a testable explanation that can be tested by experiments?

• A. Melting point
• B. Hypothesis
• C. Boiling point
• D. Steam

Answer: (B)

A hypothesis is a testable explanation that can be tested by experiments. In science, you start with a question and propose a statement that makes a specific prediction about what you expect to observe. Because it is testable, you can design experiments or observations to confirm or refute it, and it can be proven false if the results don’t match the prediction. For example, “If a metal is heated, it will expand” gives a measurable prediction you can test with measurements. The other terms describe properties or states of matter: melting point and boiling point are the temperatures at which a substance changes phase, and steam is water in gaseous form. Those are not testable explanations by themselves, so the best fit is hypothesis.