Scientific investigations involve asking and answering a question and comparing the answer with what scientists already know about the world.
Scientists use different kinds of investigations depending on the questions they are trying to answer. Types of investigations include describing objects, events, and organisms; classifying them; and doing a fair test (experimenting).
Simple instruments, such as magnifiers, thermometers, and rulers, provide more information than scientists obtain using only their senses.
Scientists develop explanations using observations (evidence) and what they already know about the world (scientific knowledge). Good explanations are based on evidence from investigations.
Scientists make the results of their investigations public; they describe the investigations in ways that enable others to repeat the investigations.
Scientists review and ask questions about the results of other scientists' work.