Teacher Notes for Experiments, Variables, and Relationships


Lesson Plans || Learning Outcomes and Activities || Teacher Notes || Labs


Unit Overview

The beginning of the year Lesson Plans are always filled with a collection of vital housekeeping tasks and relationship building tasks that must be done. Policies (yours and the schools), grading (or ungrading) practices, information about the course and how to be successful, expectations for behavior and performance, practices and expectations for the lab and for lab reporting, etc. This unit (and any first unit of the year) is the place where all that happens. But in addition to the housekeeping and relationship building tasks, this unit is where students get acquainted or re-aquainted with some big ideas that will be used throughout the course. Many of these ideas have been taught in other science classes or in math classes but deserve some review.

We are suggesting 8 days to cover all the housekeeping and relationship building tasks and to accomplish the following three goals:
  1. To develop the skill of producing a lab report that identifies a question to answer, presents evidence in the form of a Data table or graph, and answers the question by making a claim that is supported by the evidence of the data section and includes reasoning that explains why the claim is sensible in light of the reported evidence.
  2. To relate the expected graph, the generic equation, and the pattern of change for two variables to the type of relationship that exists (linear, quadratic, inverse, constant) between those variables.
  3. To calculate and make meaning of the slope of a best-fit line on a graph.


Content Shortage

The content in this unit is usually covered in the first chapter of a Physics textbook. The second chapter often has to do with Kinematics or Describing Motion. In the early years of our website, we left out this topic and essentially integrated it into the other topics on an as needed basis. As such, you will find little Tutorial information or Labs or Think Sheets on the website that pertain to topics such as experimental design, variable relationships, claim-evidence-reasoning statements, etc. In creating this unit, we have added these items separately to our Lesson Plans section. And we have linked to this content from both the Lesson Plans page and the Learning Outcomes and Activities page. For subsequent units, you will find that there is plenty of content to support the topics in the unit.


To Cover or Not To Cover

This unit is one of the units that is often skipped by teachers. For such teachers, Kinematics is the starting point and the concepts associated with lab reporting, relationships, and slope are introduced on an as-needed basis throughout the early units and the rest of the year. The assumption is that these concepts have been taught in previous courses and only require review as opposed to coverage within a whole unit devoted to the concepts. 

Either approach has merit. We've personally done it both ways and have found there to be advantages and disadvantages to each approach. The approach that works best seems most dependent upon the type of student that populates the course. Students with strong math skills are more able to adapt to the cover-as-needed approach and also more likely to be bored by the other approach. Presenting these concepts in their own unit may help students to gain greater confidence and skill. Particularly for non-honors classrooms, cultivating such skills early in the school year will give students greater confidence and less frustration as they are used in later units.


Labs and Lab Notebooks

Our approach to labs and lab reporting is definitely not the norm. We've witnessed that teachers generally prefer "Lab Sheets" that they can distribute to students that have directions, pre-made tables, follow-up questions, and a place to provide a conclusion. We've done labs that way as well. But our approach used on the website has been to skip the Lab Sheet and to provide a question and a purpose. A procedure might be suggested. The role and use of the provided equipment is usually described and often demonstrated. We sometimes flash a diagram or other graphic organizer on the screen that students can refer to. But we avoid a step-by-step procedure. 

We also tend to avoid providing data tables (though admittedly, we do sometimes provide data tables). We often describe some considerations regarding what data should be collected and how much data should be collected. But our general trend is to leave as much decision-making as is possible to the student. The more invested that students become in the decisions (even if they make bad ones), the better we feel about the value of the lab.

The use of a lab notebook facilitates this approach of leaving a large amount of the decision-making up to the student. Starting with a blank page of paper in a lab notebook creates a noticeably different vibe than having a Lab Sheet with step-by-step directions and blanks to be filled in. While we can imagine that our approach may not be for every teacher, we do believe that every teacher should at least try it. If you're hesitant about diving in but are willing to try it, we would suggest finding labs that have a very clear question and purpose. The more clear that the question and purpose is, the more it can guide student procedure within the lab. Here's two examples - one with a purpose capable of guiding students and the other quite incapable of guiding students in conducting a procedure:

Example 1 - Well-defined purpose; students can design their own procedure

Purpose: To contrast the shape and slope of the velocity-time graphs for the following types of motion:

  • moving in the + direction versus moving in the - direction
  • moving fast versus moving slow
  • a constant speed motion versus a gradually changing speed
  • a speeding up motion versus a slowing down motion
  • moving in the same direction versus changing directions
  • combinations of the above

Example 2 - Ill-defined purpose; students will not likely know how to proceed
Purpose: To determine how the shape and slope of a velocity-time graph is related to the type of motion.

The Example 1 purpose is detailed enough that a demonstration of how to use a motion detector and the stated purpose would be sufficient information for students to complete the lab without a teacher-provided step-by-step procedure. While there is nothing wrong with the purpose provided in Example 2, we just do not believe there is enough detail to inform students about what procedure they should carry out. It will either lead to a lot of questions posed by students to the teacher or it will lead to procedures that provide minimally useful end-product in terms of how shape and slope are related to the type of motion.

Our approach is one of a purpose-driven lab as opposed to a procedure-driven lab. We have provided Teacher Guides to each of our lab that provides additional details that the teacher may need in order to use the lab within their classroom. Our Teacher Guides also include scoring rubrics which we have found to help considerably with the grading process. 


Task Tracker and Student Buy-In

If you are using Task Tracker assignments (or simply using our interactive assignments without Task Tracker), then you will need to spend some time and effort selling students on the approach. This unit is a good place to begin your sales pitch.

The program works best when students understand its role in the learning cycle. The role that these activities have may vary from teacher to teacher. But in general, these activities are sense-making activities. They are an opportunity for students to reflect on the meaning of ideas conveyed through lecture, labs, discussions, etc. The activities are (or at least should be) tied to the other activities of the lesson and unit and serve to re-adjust, re-align and reinforce the understanding.

The activities also serve as self-assessments. When the understanding is strong, completion of a Concept Builder or other activity goes smoothly and the student feels like a superstar (or Master or Wizard). When the understanding is weak, the progression through the interactive material will be slower. When a student gets stuck on the same type of question, it ought to be a red flag to that student that there is something missing in their understanding of some aspect of the concept.

Students who have difficulty with our activities need to understand that there is likely an easily-correctable misunderstanding of the concept. The correction or remediation occurs when they pause, read, reflect, and adjust their conception of the idea ... and then continue. The read and reflect could include looking at class notes, reviewing any help sheet distributed by the teacher, looking over a record from an in-class activity, or using the information found by tapping on the Help Me! button.

Nearly every question of every activity includes a Help Me button that links to tutorial information that is specific to the question. It is more often than not very specific to the question. We've seen students use this information to complete activities prior to class coverage of the topic; so it clearly has tutorial value. For frustrated students having difficulty with the activity, the need is to exit their guess-and-check cycle and PAUSE. Read and Reflect. Adjust their thinking. And then continue. We like to advertise it as "the fastest way to finish the work is to slow down." It is also the less frustrating way and most satisfying way to finish the work. When such a once-frustrated student acquires that understanding and finishes the work, they will feel like a superstar (or Master or Wizard). They have climbed the proverbial ladder from zero to hero. When doing these activities in class, you will sense their satisfaction and be able to celebrate with them. It's a high-five moment! Or a Dataway moment.

Spending some time in the early units cultivating this approach will produce huge dividends. Investing in student buy-in will add tremendous value to our Task Tracker activities.


Also Available ...

Physics teachers may find the following for-sale tools to be useful supplements to our Lesson Plan and Pacing Guide section:


  1. Task Tracker Subscription (annual purchase)
    A subscription allows teachers to set up classes, add students, customize online assignments, view student progress/scores, and export student scores. Task Tracker accounts allow your students to begin assignments in class or at school and to finish them at home. View our Seat and Cost Calculator for pricing details.
  2. The Solutions Guide
    We publish a free curriculum with >200 ready-to-use Think Sheets for developing physics concepts. The Solutions Guide is a download containing the source documents, PDFs of source documents, and answers/solutions in MS Word and PDF format. An expanded license agreement is included with the purchase. (Cost: $25 download)
  3. Teacher Presentation Pack
    This is a large collection of downloadable content packed with nearly 190 Microsoft PowerPoint slide decks, the corresponding Lesson Notes (as PDF and fully-modifiable MS Word format), about 170 animations (in .gif, .png, and .mp4 file formats), a countless number of ready-to-use images (including the original source documents that would allow for easy modification of those images), and a license that allows teachers to modify and use all the content with their classes on password-protected sites (such as course management systems).  (Cost: $40 download)
  4. Question Bank
    We distribute a Question Bank that includes more than 9300 questions neatly organized according to topic. The Question Bank is the perfect tool for busy teachers or new teachers. Even if you don't use the website with your classes, the Question Bank will assist you in quickly putting together quizzes, tests and other documents with high-quality questions that target student's conceptions of physics principles. And if you do use The Physics Classroom website, the Question Bank is the perfect complement to the materials found at the website. (Cost: $25 download)