Teacher Notes for Reflection and Mirrors

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


Unit Overview

We would suggest that 11 days on this topic would be necessary to cover all Learning Outcomes. There are three primary goals:
  1. To understand why the reflection of light off a smooth, flat surface results in the formation of an image.
  2. To understand why the reflection of light off a concave or convex surface results in the formation of an image.
  3. To use qualitative and quantitative approaches to describe how the object distance affects the image characteristics for plane, concave, and convex mirror.
The first 4-5 days will be devoted to plane mirrors. The remaining time will be devoted to curved mirrors.


Time, Content, and Decisions

When it comes to planning all the Physics you wish to teach your students, time is more often the enemy than the friend. While it is difficult for us to imagine cutting anything out of a curriculum, the unfortunate reality is that there is a day on the school calendar that says Summer Break begins.

If you need to steal time from Mirrors to give time to another topic, we might suggest limiting the math at the end of the unit. Now we think the mirror equation is rather cool. Its ability to predict the same conclusions regarding image characteristics that students view in lab and the same conclusions regarding image characteristics that students learn from ray diagrams strikes us as downright groovy. But unfortunately, our giddy enthusiasm for the mirror equation has never been satisfactorily matched by students. So transfer some of those mirror equation days to doing more projectile problems (or the topic of your choosing) and we are certain you'll be quite satisfied.



This unit is as phenomenological as they come. Every outcome can begin with a lab or demonstration. The hands-on experiences do not require fancy equipment. We've suggested five labs. Our Teacher Guides suggest alternative methods. There's more lab ideas in our Laboratory section.


Other Resources

There are a few resources that we did not list in our Lesson Plans and Learning Outcomes and Activities that you may find to be very helpful. These include:
  1. Science Reasoning Center: Curved Mirrors
    Students analyze and interpret a complex diagram; identify the effect of variations in one quantity upon another quantity; draw conclusions that are supported by one or more data presentations; identify evidence that supports a conclusion; transform data from a table into a graph; and to interpolate and extrapolate from data in a table.
  2. Science Reasoning Center: Object-Image Relationships
    Students identify the effect of one variable upon another variable; select values and compare values on a graph; draw conclusions that are consistent with a data presentation (or two); combine data from two graphs in order to identify an accurate conclusion; and to interpolate using values on a graph.


Teacher Presentation Pack

We say this a lot. But we think it is worth saying. Our Teacher Presentation Pack is a huge time-saver. For early-career and cross-over Physics teachers, it may also become a life saver. It includes a large collection of Slide Decks, animations, and graphics for use in your classroom. Once downloaded, you can modify and customize the Slide Decks as needed. The slides are highly organized and (mostly) graphical; they make great graphic organizers for any student, and especially for the struggling student. Learn more.


Also Available ...

Physics teachers may find the following for-sale tools to bes 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)