Crime Lab Forensics

Students in grades 8 to 10 spend nine class periods as trainees at a student crime lab, working out who took a school's robotics trophy. They separate marker inks with paper chromatography, sort fingerprint patterns, graph shoe length against height to estimate a height, compare fibers, and check alibis on a timeline, learning that every clue has limits. Teams write a claim-evidence-reasoning lab report and defend it at a mock case review before the culprit's letter is read.

Driving question: How can a crime lab use evidence, and be honest about what it does not know, to solve the case of the missing trophy?

What's in the PDF (23 pages)

• A teacher guide with the unit overview, the materials list, and 4 teacher tips
• 9 standards with what students do for each one, and a pacing table for all 9 days
• 9 lesson plans with minutes for each part, teacher notes, and an exit ticket
• 9 student handouts: Case file: the missing Golden Gear, Evidence board, Ink chromatography lab, Fingerprint card, Shoe print and height, Fiber comparison, Timeline and alibis, Lab report: claim, evidence, reasoning, Case review planner
• A rubric with 4 rows and four score levels, and a student reflection page
• Support and extension ideas, and a plan for the final showcase

What students make

• A chromatography record with Rf values
• A fingerprint card and class tally
• A scatter plot with a line of best fit and a height range
• An evidence board that rules each suspect in or out
• A CER lab report and a three-minute case review

Day by day

Day 1, The case opens: Students read the case file and the four suspect statements, learn the difference between class and individual evidence, and set up the evidence board.

Day 2, Ink chromatography: Teams run three markers and the scene note on coffee filter strips with water and measure how far each dye travels.

Day 3, Ink results: Students find Rf values to 2 decimal places, decide which marker matches the note, and explain why some dyes travel farther.

Day 4, Fingerprint patterns: Students lift their own fingerprints with pencil graphite and tape, sort them into loops, whorls, and arches, and compare the class tally with the scene print.

Day 5, Shoe print and height: Teams plot shoe length against height, fit a line, and use it to estimate a height range for the shoe print at the scene.

Day 6, Fiber evidence: Students compare fibers under a magnifier and check the lab's line against a line from the class's own data.

Day 7, Timeline and alibis: Teams build a timeline from the logs, check every alibi, and finish the evidence board.

Day 8, The lab report: Each team writes a claim-evidence-reasoning lab report and plans a three-minute case review.

Day 9, Case review day: Teams present at the case review and answer a question, hear the culprit's letter, and write a reflection.

Standards

• NGSS MS-PS1-2 (PS1.A): Each pure substance has characteristic physical properties that can identify it.
• NGSS HS-PS1-3: Grades 9 and 10 link how far a dye travels to its attraction to water.
• CCSS 8.SP.A.1-3: Students plot the data, fit a line, and use it to estimate a height.
• CCSS HSS-ID.B.6a-c: Grades 9 and 10 fit a linear model and use residuals to set a range.
• CCSS HSS-ID.C.7 / C.8: Students interpret slope and intercept and compute and interpret r.
• CCSS HSN-Q.A.3: Students round Rf values to 2 places and report a range, not a point.
• The other 3 standards are listed in the packet.

Printing

Print the teacher pages once for yourself, and print the handouts for each student or each team. The pacing table lists the handouts you need each day. Every page is Letter size, and the handouts print clearly in black and white.

License

This file is for one household, one classroom, or one homeschool group. You may copy it for your own students. An extra license is required before you share it beyond your group.

How you get your files
After checkout, the download link is on the order page and in your confirmation email. Open the PDF and print what you need.

Questions? support@trailposteducation.com