SEPs: Planning and Carrying Out Investigations

Science and Engineering Practices: Planning and Carrying Out Investigations

Investigations are a crucial part of both science and engineering. In science, investigations help to better understand phenomena and test theories—and ultimately, answer questions. In engineering, the goal of investigations is to test designs under certain conditions, solve problems, and see if the functioning of a design can be improved. As part of any science or engineering investigation, the first—and very critical—step is to set up appropriate parameters. You don’t just dive into an experiment or observation; you state your goals and make predictions (based on a scientific question), identify your variables, or even make a model. In other words, you formulate a solid plan. 

There are various types of scientific investigation, each suited to different circumstances. People usually think of scientists in lab coats with Petri dishes and microscopes when they imagine scientific investigations, but scientists also carry out investigations in the field, make observations, or investigate through secondary research.

Planning and Carrying Out Investigations: Progression

Primary School (K–2)
1. With guidance, plan and conduct an investigation in collaboration with peers.
2. Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question.
3. Evaluate different ways of observing and/or measuring a phenomenon to determine which way can answer a question.
4. Make observations (firsthand or from media) to collect data that can be used to make comparisons.
5. Make observations (firsthand or from media) and/or measurements of a proposed object or tool or solution to determine if it solves a problem or meets a goal.
6. Make predictions based on prior experiences.
Elementary School (3–5)
1. Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered.
2. Evaluate appropriate methods and/or tools for collecting data.
3. Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon or test a design solution.
4. Make predictions about what would happen if a variable changes.
5. Test two different models of the same proposed object, tool, or process to determine which better meets criteria for success.
Middle School (6–8)
1. Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.
2. Conduct an investigation and/or evaluate and/or revise the experimental design to produce data to serve as the basis for evidence that meet the goals of the investigation.
3. Evaluate the accuracy of various methods for collecting data.
4. Collect data to produce data to serve as the basis for evidence to answer scientific questions or test design solutions under a range of conditions.
5. Collect data about the performance of a proposed object, tool, process, or system under a range of conditions.
High School (9–12)
1. Plan an investigation or test a design individually and collaboratively to produce data to serve as the basis for evidence as part of building and revising models, supporting explanations for phenomena, or testing solutions to problems. Consider possible variables or effects and evaluate the confounding investigation’s design to ensure variables are controlled.
2. Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.
3. Plan and conduct an investigation or test a design solution in a safe and ethical manner including considerations of environmental, social, and personal impacts.
4. Select appropriate tools to collect, record, analyze, and evaluate data.
5. Make directional hypotheses that specify what happens to a dependent variable when an independent variable is manipulated.
6. Manipulate variables and collect data about a complex model of a proposed process or system to identify failure points or improve performance relative to criteria for success or other variables.

Grades K–2: Progression

It’s important to allow younger students to start (with guidance) planning their own investigations from the early elementary grades.

In K–2, students can carry out simple investigations that provide data to support explanations or design solutions.1 This will help them start to understand the importance of planning and carrying out investigations in science.

Introduce students to investigations in science by helping them plan “controlled investigations”—also known as a fair test. For example, let’s say our question is “What do plants need to survive?” First, ask your students what they think plants need to survive. Discuss this as a class, encourage them to ask questions and formulate theories, and have them think about what they, as humans, need to survive. Agree on a hypothesis: plants need X and X to survive (water and sunlight). So how do we gather the data we need? By conducting a (fair test) investigation using four seedlings. 

– The first seed will receive no sunlight and no water
– The second seed will receive sunlight but no water
– The third seed will receive no sunlight but will get water
– The fourth seed will receive sunlight and water

Across a few weeks, observe the seedlings’ growth as a class. Ask questions: do the students still think that their hypothesis is correct? Remind them that it’s OK if their hypothesis turns out not to be correct—being wrong is just a part of the scientific process and brings us closer to the “right” answer.

With any investigation in the science classroom, where you do have a predetermined plan, it’s very important to include the students in the planning process and to work through each step with them.

Grades 3–8: Progression

In the example above, the investigation would be carried out as a class, but by Grades 3–5, science investigations can progress to something a little more complex, and students should become comfortable planning and carrying out investigations with a little less guidance. They should be encouraged to choose their own tools for data collection and start to include control variables (elements that will remain unchanged throughout any experiment). The students could design an investigation to determine how to best transfer energy by building a propulsion mechanism for a toy car—the car (the control variable) will always remain the same but the materials (the independent variables) that they choose to use for propulsion will change. To get your students used to verifying the validity of investigations, you could repeat this experiment and see if the data collected remains the same or changes. 

In middle school, students will use all that they have learned in elementary school together—planning their investigations (independently, or in small groups), deciding the appropriate experimental variables, providing evidence, and designing solutions. They should also start to choose their tools to analyze and evaluate their data. 


Learn More About Planning and Carrying Out Investigations with Twig Science

Download our free printable Planning and Carrying Out Investigations poster to serve as a reminder for your students that this practice is an important part of the process of scientific investigations.  

To ensure that you hit the three dimensions of science learning, you need the support of a comprehensive 3-D science program. Twig Science is a phenomena-based science program that ensures all students have an interwoven understanding of Crosscutting Concepts, Science and Engineering Practices, and Disciplinary Core Ideas.