Inspector Detector Challenge

Type Category
Instructional Materials
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



Students use the engineering design process to design and build magnetic-field detectors, and use them to find hidden magnets. Parallels are drawn to real-world NASA missions and how NASA scientists use magnetic field data from planets and moons. The website has video clips, teaching suggestions, a student handout, and a link to the pdf of the Teacher’s Guide for Mission: Solar System. The Inspector Detector challenge is a series of activities that form a unit in the Mission: Solar System collection. * NOTE: The Teacher’s Guide does not contain the lesson plan. You will need to click on the Student Handout heading of the website to download the “Inspector Detector Challenge Leader’s Notes”. Or you can go to the Design Squad webpage ( Related Resources) to download the Mission: Solar System full guide.

Intended Audience

Educational Level
  • Middle School
Access Restrictions

Free access with user action - The right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use.

Performance Expectations

MS-PS2-5 Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other even though the objects are not in contact.

Clarification Statement: Examples of this phenomenon could include the interactions of magnets, electrically-charged strips of tape, and electrically-charged pith balls. Examples of investigations could include first-hand experiences or simulations.

Assessment Boundary: Assessment is limited to electric and magnetic fields, and limited to qualitative evidence for the existence of fields.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
The purpose of the activity is to design and use a device that can detect magnets hidden under a newspaper. The only way that the device can work is if objects are able to exert forces on each other even when not in contact. Thus, a successful use of the device leads toward an understanding that magnetic fields extend through space and that magnetic forces can act at a distance. The resource does not address electrical or gravitational forces and fields Note: The introductory video, titled “Inspector Detector Challenge” should NOT be shown to most students, as it “gives the game away” by telling the students up front about fields, and showing two ways to build a magnetic field detector.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The focus of the activity is using the engineering design process to find a solution to a problem: “Where is the magnetic field felt on this simulated planet?” Criteria and constraints for the design are given in the lesson. Teachers should use this vocabulary to overtly point out the criteria and constraints to students. The lesson plan specifically refers to steps of the design cycle “Build, test, evaluate, and redesign”. To strengthen this focus on design, offer more types of materials for students to choose from. As written, students only engage in evaluating, redesigning and rebuilding after the culminating challenge, and only if they feel it is necessary. A “testing station” where students can use their prototype designs with magnets would allow students to evaluate and redesign their detectors before committing to a design to use for the culminating challenge of detecting magnets hidden under newspapers. While the Mission: Solar System Guide PDF mentions that the Inspector Detector challenge addresses six of the the NGSS Practices, it does not include specifics. The PBS Learning Center website’s “Teaching Tips” gives some rather vague and generic tips to incorporate Defining Problems, and Engaging in Argument, which could inspire a teacher, though the tips themselves do not address the whole of either of those practices.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The introductory portion of the lesson brings in the idea of fields. While the challenge video clip, “Inspector Detector Challenge” does so also, it is NOT recommended that teachers show the entire video as an introduction, as the video tells, rather than having students discover. The segment from 0:42 to 1:15, about how and why NASA uses magnetometers, would be appropriate to show at the end of the lesson, to make the connection between what the students have done and what NASA engineers do. An alternate video, about NASA’s MAVEN magnetometer, is available on YouTube at The devices that students build will be able to work to solve the problem, because fields extend through space. The devices allow students to map the effect of the field, figuratively by looking at their devices, and literally with a grid system.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
The patterns created by the magnetic field on the magnetometer are what allow the students to recognize the cause (invisible magnetic field) having an effect (moving magnetometer pieces in a predictable way). The lesson as written focuses on this idea of the tool responding by creating patterns. The lesson could be enriched or extended by adding a component about how magnetism works. A teacher would need to go into more detail about lines of magnetic force, and would need to include some activities and/or demonstrations that specifically show the patterns made by lines of magnetic force around a magnet, e.g. having students “map” the responses of a compass to a bar magnets, and/or draw their observations of iron filings reacting to differently-shaped magnets. The class would then have a discussion about the reason that those observed patterns are formed.

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
This lesson has students build a structure (magnetometer) to serve a function (detect magnetic fields). The way they build the magnetometer, and the reason the magnetometer will work, relies on an understanding of the properties of the materials offered and how they might be combined. The Mission: Solar System Guide does not use the exact words “structure” or “function”, so teachers will need to highlight this connection with the class, either as students begin designing their magnetometers or after they have used them.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This activity cleaves to the spirit of NGSS in the way it makes a natural connection between a science concept and engineering design. The lesson makes it very easy to highlight a practice and a crosscutting concept. Students blend these strands together as they solve a problem.

  • Instructional Supports: Real-world connections are strong - students use real objects and, while they are not exploring other planets themselves, the video clips make it clear that this is something that is really happening, and that real engineers are working on. The combination of video clips and students’ own engineering is strong. Instructions for differentiation are not given, but the lesson offers several opportunities where a teacher could make this happen (e. g., show different video clips to different groups, be more or less specific with examples of magnetometers, have more or less challenging “planetscapes”). A weakness of the lesson lies in a lack of opportunity for students to communicate their findings, give and respond to feedback. The lesson as written has no place for that, though it’s hinted that this could happen during the “evaluate and redesign” phase of engineering design.

  • Monitoring Student Progress: This lesson has a rubric at the end, but the rubric addresses only practices and teamwork, not the DCI or cross cutting concepts . The Leader Guide gives questions to ask before and after the activity, but many are closed-ended, and there is no information for the teacher about how to use these as formative assessments.

  • Quality of Technological Interactivity: This lesson does not include interactive technology. With regard to computer technology in general, the videos played smoothly, the site login worked fine, and the PDF files downloaded without trouble. The videos can be downloaded if internet connectivity is an issue.