Prism Lab Lesson Plan Guided Notes Teacher ResourcePrism Lab: Mirror World Mission Briefing & Field Notes Subject: Geometry / Transformations Topic: Intro to Reflections Name: __________________________ Date: ___________________________ Learning Objectives Identify and draw lines of reflection (mirrors). Reflect points and shapes across the x and y axes. Verify that reflected figures remain congruent. Key Vocabulary Reflection: A "flip" over a line. Line of Reflection: The mirror line. Pre-image: The original figure. Image: The new figure (labeled with '). Guided Field Notes 1. What is a Reflection? A reflection is a transformation that creates a mirror image. Every point in the image is the same _______________ from the line of reflection as the corresponding point in the pre-image. L Pre-image L Image 2. The Mirror Rules When reflecting over an axis, the coordinates change in a specific way: Over the X-Axis: (x, y) → (_____, _____) The x stays the same, the y flips its sign! Over the Y-Axis: (x, y) → (_____, _____) The y stays the same, the x flips its sign! 3. Congruence Check After a reflection, does the shape change size or shape? _________ Because they are the same size and shape, the pre-image and image are CONGRUENT. Lab Practice: Identifying Mirrors Look at the pairs below. Draw the line of reflection (the mirror) for each. Teacher Implementation Guide Hook (5-10 mins) Ask students if they've ever noticed writing on the front of an ambulance. Why is it backwards? Discuss how drivers see it "flipped" in their rear-view mirror so they can read it correctly. Instruction (15 mins) Use the Anchor Chart (provided) to demonstrate the x and y axis rules. Emphasize that "reflect" means "equal distance from the mirror." Have students physicalize this by standing a certain number of floor tiles away from a wall (the mirror) and asking where their "reflection" would be. Guided Practice (15 mins) Complete the Guided Field Notes together. For the coordinates section, use a specific point like (2, 3) and plot it on the board. Then reflect it over the x-axis to show it lands at (2, -3). Common Misconception Students often think reflecting over the X-axis changes the X-coordinate. Remind them: Jump OVER the x-axis? You are moving vertically (y changes).
Mirror Mission WorksheetMirror Mission Prism Lab: Reflection Analysis Name: Date: 1 Spot the Mirror For each pair of figures, draw the line of reflection (the mirror) that would create the image. A B 2 Coordinate Jump Apply the reflection rules to find the coordinates of the reflected image. Pre-image PointLine of ReflectionImage Point (x', y')A (3, 5)x-axisA' ( _____, _____ )B (-4, 2)y-axisB' ( _____, _____ )C (0, -7)x-axisC' ( _____, _____ )D (-2, -3)y-axisD' ( _____, _____ ) 3 Mirror Master Reflect triangle **PQR** over the **y-axis**. Plot and label the image **P'Q'R'**. P Q R Final Conclusion: Are the pre-image and the image congruent? How do you know? Critical Thinking: If a point lies exactly ON the line of reflection, where will its image be?
Reflection Protocol Anchor ChartInternal Reference: Doc #REF-01 Reflection Protocol The Science of Mirroring Shapes X Across the X-Axis (x, y) (x, -y) Transformation Rule (x, y) → (x, -y) "Keep the X, Flip the Y" Y Across the Y-Axis (x, y) (-x, y) Transformation Rule (x, y) → (-x, y) "Keep the Y, Flip the X" Congruence Size and shape never change. Distance Points stay equidistant from the axis. Isometry Reflections are a type of rigid motion.
Reflection Challenge Cards Activity ResourceReflection Challenge Cards Prism Lab: Interactive Task Set Material ID: TASK-REF-04 TASK 01 Coordinate Jump Point A is located at (4, -7). What are the coordinates of the image A' after a reflection over the x-axis? Answer Area ( ____ , ____ ) TASK 02 Identify the Mirror Point B (-3, 2) reflects to B' (3, 2). Which axis was used as the line of reflection? Answer Area _________________ TASK 03 Visual Reflection Reflect the segment across the y-axis. Hint: Count the distance to the y-axis for each endpoint. TASK 04 The Congruence Lab Triangle ABC is reflected to A'B'C'. If the perimeter of ABC is 24 units, what is the perimeter of the image A'B'C'? Answer Area ________ units Why? _________________________ TASK 05 Quadrant Quest A shape is located in Quadrant II. If it is reflected over the x-axis, in which quadrant will its image land? Quadrant I Quadrant II Quadrant III Quadrant IV Circle your answer! TASK 06 Stationary Points Point K is located at (0, 5). What is its coordinate after a reflection over the y-axis? Answer Area ( ____ , ____ ) TASK 07 Double Flip Point L (1, 1) is reflected over the x-axis, then that new point is reflected over the y-axis. Where does it end up? Answer Area ( ____ , ____ ) TASK 08 Reflection Truths Reflections preserve orientation. Reflections preserve side lengths. Reflections preserve angle measures. Check the boxes that are TRUE for all reflections.
Mirror Calibration Warm Up Activity ResourceMirror Calibration Prism Lab: Daily Warm Up Mission Day: 01 Lab Access: Grade 8 Researcher Name: Date: 01 The Selfie Paradox Imagine you are wearing a t-shirt with the word GEOMETRY on it. You take a selfie using the front camera of your phone. GEOMETRY Real Life GEOMETRY Selfie Preview Observation: The selfie preview is a of reality. Why does the phone do this? ___________________________________ 02 Line of Symmetry Check A reflection "flips" a shape over a line. For the figure below, draw one line that perfectly splits the shape into two mirroring halves. 03 Lab Prediction If you reflect a small square, will the reflection be a bigger square, a smaller square, or the exact same size? Bigger Smaller Same Size
Reflection Protocol Exit Ticket Assessment ResourceMission Debrief Exit Ticket: Reflection Protocol Doc #EXIT-01 Researcher: Date: 1. Coordinate Transformation Point P (-5, 3) is reflected over the y-axis. What are the coordinates of the image P'? ( ____ , ____ ) 2. Identify the Axis A triangle starts in Quadrant I. After a reflection, its image is in Quadrant IV. Which axis was it reflected over? X-Axis Y-Axis Circle your answer 3. Property Check True or False? A reflection can change the area of a shape. TRUE FALSE Confidence Level Cut here for next mission
Mirror World Instructional SlidesPrism Lab: Unit 04 Mirror World Introduction to Geometric Reflections Scanning for symmetry... ? The Selfie Paradox Why do you look different when you take a selfie compared to a regular photo? "Your front-facing camera shows you a mirror image so you can pose, but the final photo often 'flips' back to reality." Which version is the "real" you? Mirror View Final Image What is a Reflection? A Reflection is a transformation that "flips" a figure over a line. The resulting figure is a mirror image of the original. The line is called the Line of Reflection. F Pre-image F Image X The X-Axis Rule (x, y) → (x, -y) When you reflect across the X-axis, the X-coordinate stays the same, but the Y-coordinate becomes its opposite. "Keep the X, Flip the Y" (4, 3) (4, -3) Y The Y-Axis Rule (3, 5) (-3, 5) (x, y) → (-x, y) When you reflect across the Y-axis, the Y-coordinate stays the same, but the X-coordinate becomes its opposite. "Keep the Y, Flip the X" Congruence Check True or False? Reflections change the size of the original figure. FALSE Reflections produce CONGRUENT figures! ! Lab Challenge Predict the coordinates of the image: A (2, -4) Reflect X-Axis B (-6, 0) Reflect Y-Axis Solution Reveal A' (2, 4) B' (6, 0) Mission Complete Reflection Protocol Initialized. Next Phase Complete Mirror Mission Worksheet Team Task Challenge Card Station Rotation Exit Scan Submit Reflection Protocol Ticket
Reflection Master Key Teacher ResourceMaster Key Complete Lesson Solutions Teacher Resource Mirror Calibration 1. Selfie Paradox: The preview is a reflection or mirror image. Phones do this so the camera acts like a mirror (easier to pose), but the saved photo is often flipped back to show what others actually see. 2. Symmetry: A vertical line straight down the center of the butterfly shape. 3. Prediction: "Same Size" (Reflections are rigid motions). Mirror Mission 1A: Vertical line center. 1B: Horizontal line center. 2: A'(3,-5), B'(4,2), C'(0,7), D'(2,-3) 3: P'(-2,2), Q'(-5,2), R'(-2,6). Congruent: Yes. Challenge Cards T1: (4, 7) T2: Y-Axis T3: End (-2, 2) & (-5, 5) T4: 24 units T5: Quadrant III T6: (0, 5) T7: (-1, -1) T8: Lengths, Angles Mission Debrief 1. Coordinate: P' (5, 3). (Y-axis flip changes the X-sign). 2. Axis: X-Axis. (Moving from Quad I to IV is a vertical flip). 3. Property: FALSE. (Reflections preserve area/congruence). Total Mission Points: 100 Prism Lab Geometry Series © 2026
