Newton's First Law: Inertia Kills Investigation

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SWBAT determine how mass affects the inertia of an object made of matter.

Big Idea

Spinning eggs! Tablecloth magic tricks! Newton's first law of motion can explain it all!


10 minutes

Inertia is a tough word to pronounce; it is also a tough concept to conceptualize accurately. The good news is that Newton's 1st Law - the law of inertia - explains many fun, engaging and important phenomena. In this investigation, students spin eggs, do tablecloth magic and cut stacks of coins with a knife - all in the name of evaluating how the mass of an object affects its inertia.

Being a guided inquiry investigation, students use several science practices in order to plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object (MS-PS2-2). These practices include: develop a model to show the relationships among variables, including those that are not observable but predict observable phenomena (SP2); plan and conduct an investigation 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 (SP3); construct an explanation that includes qualitative or quantitative relationships between variables that predict and describe phenomena and uses models or representations (SP6); and construct, use, or present a written argument supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon or a solution to a problem (SP7).

Students also interact with three different investigations that can help them model how inertia contributes to interactions within a system, which is a direct link to the cross-cutting concept that Models can be used to represent systems and their interactions (CCC).

In order to ENGAGE students in this lesson, I use a variety of multimedia resources as listed in Inertia Kills Experimental Engagement. An important note for this lesson is that the concept of inertia needs to be thoroughly introduced prior to the investigation. A lesson like Newton's Laws Graffiti can meet this student need. Additionally, it is important to pose the authentic problem students will solve using the conceptual understanding gained in the investigation. This problem is: Why should we wear a helmet when riding the Costa Rican Jungle Slide? The resources listed support the introduction and setting the purpose for this problem.


50 minutes

The EXPLORE stage of the lesson is to get students involved in the topic so that they start to build their own understanding. To help students explore, in groups, students plan their investigation using the Inertia Kills Experimental Design Plan. This is a structured inquiry lab in which students complete some sections of the plan while other sections are provided. For more on this strategy, view: Structured Inquiry is Still Inquiry. Each student records on their own experimental design plan. At this point in the year, my students have designed several experiments, so they don't require much instruction or guidance during the process other than to coach them to use precise scientific vocabulary in sections like "Procedure" and complete reasoning in sections like "Hypothesis" as shown in the Inertia Kills Investigation Student Example.

By having each student record the design plan, students are more apt to be engaged with and learn the experimental design process. Since students vary in their ability to understand experimental design, I can review student work to assess for gaps in individual understanding.

Once students have completed the experimental design plan, they are ready to conduct the investigation using the Inertia Kills Experimental Procedure.  The following videos illustrate each part of the procedure.

Inertia Kills Experimental Procedure Part 1:

Inertia Kills Experimental Procedure Part 2:

Inertia Kills Experimental Procedure Part 3:

Upon completion of the exploration stage, students move on to data analysis and evaluation of learning in the EXPLAIN stage of the lesson.


50 minutes

The EXPLAIN stage provides students with an opportunity to communicate what they have learned so far and figure out what it means. This stage of the lesson presents a great place for a quick formative assessment. The first strategy for helping students explain what they have learned is to individually complete the Newton's Laws Notes Student Handout for Newton's 1st Law. By completing these notes, students are able summarize the basic concepts related to inertia. Upon completion, students review their notes with a copy of the completed Newton's Laws Student Notes.

A second "explain" strategy is for students to choose to answer an analysis question or complete a quiz. The analysis questions students may choose from are:

1) In terms of inertia, explain why the eggs react differently when you try to spin and stop them. Explain your reasoning.

2) Describe how mass affected your “Tablecloth Experiment”.  Which bottle had more inertia? Illustrate your answers.

An example of the quiz can be found here: Newton's First Law of Motion Quiz.

The EXTEND stage allows students to apply new knowledge to a novel situation. The novel situation in this case is applying the conceptual understanding gained in the investigation to the authentic problem:

Why should we wear a helmet when riding the Costa Rican Jungle Slide?

A document with this prompt is included here: Inertia Kills Investigation Final PACER Argument Prompt. This is an excellent opportunity to talk with students about models and systems. The learning students do will be enhanced when they realize that the eggs are modeling the skull when thinking about concussions and helmets. Additionally, inertia is a property of matter that affects the motion of objects within systems. Some students make these leaps themselves; for other students it is important to used discussion and images to help connect the dots. For an example of student work regarding this prompt, check out: Inertia Kills Investigation Final PACER Argument - Exemplar.


The EVALUATION stage is for both students and teachers to determine how much learning and understanding has taken place. There are many opportunities for assessment built into this investigation depending on the the goals of the lesson:

1) Assessment of planning and carrying out an investigation (SP3 - Inertia Kills Experimental Design Plan).

2) Models (SP2 - Inertia Kills Investigation Final PACER Argument Prompt).

3) Constructing Explanations (SP6 - Inertia Kills Investigation Final PACER Argument Prompt).

4) Written Arguments (SP7 - Inertia Kills Investigation Final PACER Argument Prompt).

5) Core Disciplinary Ideas: A Change in an object’s motion depends on the sum of the forces on the object and the mass of the object (MS-PS2-2 - Newton's First Law of Motion Quiz or Analysis Questions or Inertia Kills Investigation Final PACER Argument Prompt).

In order to extend or remediate learning, we may also use Newton's Laws of Motion Interactive Presentation as a supplementary tool to explore the laws. This presentation includes links to simulations, examples and questions that can be used for assessment.