Shattered Secrets Slides
SHATTERED SECRETS
Case File: GLASS-2026
Forensic Evidence Scavenger Hunt
The Briefing
A break-in occurred at the Crystal Museum.
Thief escaped through a window, leaving behind glass shards.
"The physics of glass never lies—if you know how to read it."
Objectives
- Identify Fracture Patterns
- Determine Order of Impact
- Match Density and Index
SITE A: FRACTURES
TASK 1
EXHIBIT 01
Identify these on your Evidence Tracker:
PATTERN A: Cracks that radiate like spokes on a wheel.
PATTERN B: Cracks that form circles around the impact.
SITE B: IMPACT ORDER
TASK 2
The T-Junction Rule
When glass breaks, new cracks stop at pre-existing cracks.
Which impact hit first? #1 or #2?
#1 #2
LAB: DENSITY TEST
Analysis Room
Sample A
A
Floats in middle
D = 2.5 g/cm³
Sample B
B
Sinks to bottom
D = 2.5 g/cm³
Conclusion?
Which sample is MORE DENSE than the liquid?
FACT: If an object SINKS, its density is GREATER than the liquid.
THE BECKE LINE
TASK 3
Optical Matching
When glass and liquid have the SAME RI, the glass vanishes.
Match Task:
Find the oil slide where the glass vanishes.
SLIDE A
HALO PRESENT
SLIDE B
GLASS VANISHED
CASE CLOSED
Final Report
Who broke into the museum?
Suspect #1
Evidence Match Found
Suspect #2
No Forensic Tie
Evidence Tracker Worksheet
Evidence Tracker
Case File: GLASS-2026 / Museum Investigation
Investigator:
1
Site A: Fracture Analysis
RADIAL CRACKS Definition
CONCENTRIC CRACKS Definition
Exhibit 01 Log
Pattern A (Spokes):
Pattern B (Circles):
2
Site B: Sequence of Impacts
Which hole hit first?
#1
#2
Justification (The T-Junction Rule):
Sketch Reconstruction
Lab Analysis & Verdict
Part A: Density Testing
| Sample | Observations | Result vs. 2.5 g/cm³ |
|---|
| Suspect A | | |
| Museum B | | |
Part B: Optical Match
Slide 1 (Halo)
Slide 2 (Vanished)
Why does an RI match make glass invisible?
Final Verdict
Innocent
Guilty
Summary of Proof:
Forensic Integrity Division • Case Closed
Investigator Key
Lead Investigator Key
Teacher Reference • Case: GLASS-2026
Official Use Only
1. Site A: Fracture Analysis
Radial
Cracks radiating outward from point of impact like spokes.
Concentric
Cracks forming circles around the point of impact.
Pattern A:RADIAL
Pattern B:CONCENTRIC
2. Site B: Impact Order
HOLE #1 HIT FIRST
Radial fractures from #2 stop when they reach existing fractures from #1. This is the T-Junction Rule.
STOPS AT PRE-EXISTING
3. Lab Analysis Results
Density (Float/Sink)
- Suspect A:Matches (2.5)
- Museum B:Sinks (>2.5)
Refractive Index
OIL SLIDE 2 MATCH
RI Match = No refraction = Glass vanishes.
Verdict: GUILTY
Suspect A glass matches the museum evidence on both Physical (Density) and Optical (RI) properties.
Pacing Guide
45-60 min. Spend ~10 min per "Site" slide to allow for discussion of the T-Junction rule.
Misconception
Remind students that invisibility (RI match) is the goal, not high visibility.
Teaching Note
Emphasize how Density and RI together turn "class evidence" into a much stronger match.
