12E/P1 ( Grades: K-2 ): Ask "How do you know?" in appropriate situations and attempt reasonable answers when others ask the same question.
1A/P1 ( Grades: K-2 ): When a science investigation is done the way it was done before, we expect to get a very similar result.
1A/P2 ( Grades: K-2 ): When a science investigation is done again in a different place, we expect to get a very similar result.
NSTA National Science Education Standards
2.1 ( Grades: K-12 ): Evidence consists of observations and data on which to base scientific explanations. Using evidence to understand interactions allows individuals to predict changes in natural and designed systems.
2.3 ( Grades: K-12 ): Scientific explanations incorporate existing scientific knowledge and new evidence from observations, experiments, or models into internally consistent, logical statements. Different terms, such as "hypothesis," "model," "law," "principle," "theory," and "paradigm" are used to describe various types of scientific explanations. As students develop and as they understand more science concepts and processes, their explanations should become more sophisticated. That is, their scientific explanations should more frequently include a rich scientific knowledge base, evidence of logic, higher levels of analysis, greater tolerance of criticism and uncertainty, and a clearer demonstration of the relationship between logic, evidence, and current knowledge.
A.1.1.a ( Grades: K-4 ): This aspect of the standard emphasizes students asking questions that they can answer with scientific knowledge, combined with their own observations. Students should answer their questions by seeking information from reliable sources of scientific information and from their own observations and investigations.
A.1.2.a ( Grades: K-4 ): In the earliest years, investigations are largely based on systematic observations. As students develop, they may design and conduct simple experiments to answer questions. The idea of a fair test is possible for many students to consider by fourth grade.
A.1.3.a ( Grades: K-4 ): In early years, students develop simple skills, such as how to observe, measure, cut, connect, switch, turn on and off, pour, hold, tie, and hook. Beginning with simple instruments, students can use rulers to measure the length, height, and depth of objects and materials; thermometers to measure temperature; watches to measure time; beam balances and spring scales to measure weight and force; magnifiers to observe objects and organisms; and microscopes to observe the finer details of plants, animals, rocks, and other materials. Children also develop skills in the use of computers and calculators for conducting investigations.
A.2.1 ( Grades: K-4 ): Scientific investigations involve asking and answering a question and comparing the answer with what scientists already know about the world.
A.2.2 ( Grades: K-4 ): 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).
A.2.5 ( Grades: K-4 ): Scientists make the results of their investigations public; they describe the investigations in ways that enable others to repeat the investigations.
D.2.1 ( Grades: K-4 ): The sun, moon, stars, clouds, birds, and airplanes all have properties, locations, and movements that can be observed and described.
E.1.2.a ( Grades: K-4 ): Students should make proposals to build something or get something to work better; they should be able to describe and communicate their ideas. Students should recognize that designing a solution might have constraints, such as cost, materials, time, space, or safety.
E.2.5 ( Grades: K-4 ): Tools help scientists make better observations, measurements, and equipment for investigations. They help scientists see, measure, and do things that they could not otherwise see, measure, and do.