The Stamp Factory

Common Core standards covered

• 8.G.A.1Verify experimentally the properties of rotations, reflections, and translations:
• 8.G.A.1.aLines are taken to lines, and line segments to line segments of the same length.
• 8.G.A.1.bAngles are taken to angles of the same measure.
• 8.G.A.1.cParallel lines are taken to parallel lines.

© Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

Teacher-facing overview

Big idea: Verify experimentally that rotations, reflections, and translations take segments to segments of the same length, angles to angles of the same measure, and parallel lines to parallel lines.

Student target: “I can verify by measuring that slides (translations), flips (reflections), and turns (rotations) keep side lengths, angle measures, and parallel lines unchanged.”

Success criteria: I can measure and record the sides and angles of a figure and its image. · I can verify that all three rigid motions preserve length and angle. · I can verify that parallel segments stay parallel after any press. · I can state what a rigid motion CAN change: position and orientation only.

Essential question

A stamp slides, flips, or turns before it lands — so what makes every print still count as the SAME logo?

Learning target: I can verify by measuring that slides (translations), flips (reflections), and turns (rotations) keep side lengths, angle measures, and parallel lines unchanged.

Success criteria

• I can measure and record the sides and angles of a figure and its image.
• I can verify that all three rigid motions preserve length and angle.
• I can verify that parallel segments stay parallel after any press.
• I can state what a rigid motion CAN change: position and orientation only.

Why this matters

8.G.A.1 asks students to VERIFY the properties experimentally, and a factory quality-control report is that verification with a clipboard: measure the master, measure the print, compare line by line. It also builds the exact vocabulary — image, preserved, rigid — that Transformation Studio assumes when it asks students to find which sequence of motions maps one congruent figure onto another. This is the measuring lesson; the studio is the proving lesson.

Students should already be able to

• Plotting points and reading coordinates in quadrant I.
• Measuring segment lengths on a grid (count, or Pythagorean for slants).
• Recognizing right angles and parallel segments.

Vocabulary to define explicitly

• Translation (the slide press)

  Every point moves the same distance in the same direction.

  Example: Logo corner (1, 1) slides +5 right, +2 up to (6, 3) — and so does every other point.

  Not an example: Moving one corner 5 and another corner 3 is a stretch, not a slide.

🔒 3 more terms with examples and non-examples — Reflection (the flip press), Rotation (the turn press), Rigid motion — are defined in the full lesson. See plans →

Where this shows up outside the classroom

Assessment plan

Formative — for feedback during the lesson

• Warm-up never/can lists.
• Report rows during QC floor work — the rotation row especially.
• The impostor verdict and its justification.

Summative — the graded evidence: The exit ticket (image endpoints, preserved angle, allowed changes), scored with the four-criterion rubric.

The task students work on

LogoPress Inc. stamps a triangular logo onto products. The master logo L has corners (1, 1), (4, 1), (1, 3). Three presses each make one print: the SLIDE press moves the stamp right 5 and up 2; the FLIP press mirrors it across the line x = 6; the TURN press rotates it a quarter turn counterclockwise about the point (6, 6). Your quality-control team measures every print and certifies — or rejects — each press.

Quality-check report — one row per press. Master measurements: bottom 3, left 2, slant √13 ≈ 3.6, right angle at A.

Anticipated student strategies

Measure-and-compare first because it is the verification itself; corner tracking second to explain the landing spots; the overlay last to cement that 'congruent' means 'lies exactly on top.'

1. Count-and-compare. The student counts grid units for the horizontal and vertical sides of master and image, and checks the slant with the Pythagorean theorem (3² + 2² = 13 both times).

   The intended method. Share first — the row-by-row match IS the verification the standard asks for.

🔒 2 more anticipated strategies with select-and-sequence guidance are in the full lesson. See plans →

Lesson script

🔒 The remaining 4 steps — fully scripted with teacher-says lines, discourse questions, look-fors, and interventions — are in the full lesson. See plans →

Misconceptions and how to respond

• “The flipped print is a different logo because it reads backwards.” Measure it: every side and angle matches the master. Orientation is on the CAN-change list; lengths and angles are not. Backwards and congruent.
• “The turn press moves the center too.” — the teacher response is in the full lesson.
• “Slant sides can be counted like gridline sides.” — the teacher response is in the full lesson.
• “If it looks the same size, it's certified.” — the teacher response is in the full lesson.

🔒 Every misconception ships with a tested classroom response. See plans →

Scaffolded practice

The workbook follows gradual release rather than a page of blank prompts: 1 fully worked, 1 partially completed, then 4 independent.

1. I doVerify the slide press: master (1,1), (4,1), (1,3); print (6,3), (9,3), (6,5). Measure both triangles and give the verdict.

🔒 5 more prompts across all three release tiers are in the full lesson. See plans →

Worked solutions and scaffolds for every prompt are in the downloadable kit, included with membership. See plans and pricing.

Exit ticket

1. A slide press moves every point +3 right, +4 up. The master segment runs (2, 2) to (6, 2). Give the image segment's endpoints and its length.

🔒 2 more exit-ticket questions are in the full lesson. See plans →

Worked answers, the completed answer tables, and the scoring rubric are in the downloadable kit, included with membership. See plans and pricing.

Printable handouts in the kit

All handouts are in Printable_Handouts.pdf inside the kit download.

Materials and classroom resources

Student experience

Students enter through a low-floor prompt, build or sketch a model, test a strategy, revise their thinking, collaborate, and present a final solution. The task remains accessible while allowing for sophisticated reasoning.

Detailed facilitation notes

1. Step 1: Measure the master logo's sides and angles. Ask: “What do you notice?”, “What could you try next?”, and “How can you prove that?”
2. Step 2: Check the slide press output against the master. Ask: “What do you notice?”, “What could you try next?”, and “How can you prove that?”
3. Step 3: Check the flip press and turn press. Ask: “What do you notice?”, “What could you try next?”, and “How can you prove that?”
4. Step 4: Write the factory's guarantee. Ask: “What do you notice?”, “What could you try next?”, and “How can you prove that?”

Differentiation and inclusion

Support: One press at a time, whole-number coordinates, and a fixed checklist (sides, angles, parallels) to verify. Extend by asking which press was used given only the master and one print — Transformation Studio's opening puzzle.

Language support: “I started by…”, “My model shows…”, and “I know my answer is reasonable because…”.

Extension: Require a second solution, alter a condition, or have students write a challenge for another group.

Accessibility: Manipulatives, enlarged visuals, oral response choices, partner reading, and reduced-copy student pages.

Assessment plan

Formative checks: Strategy choice, accuracy, representation, collaboration, and explanation.

End evidence: One completed quality-check report with measurements for all three presses.

Mastery: The student completes the task accurately and explains the strategy with limited prompting.

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