Unit 1.1 Investigating the Scene: Forensic scene documentation, evidence log, crime-scene sketch, trace evidence, biometric data.
What to do if absent- CER:
- Claim, Evidence, Reasoning — make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure — the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities — you open it through Schoology.
Week overview - Investigating the Scene: documenting evidence like a forensic scientist
Document a mock scene with a sketch and an evidence log, examine trace evidence under the microscope, and tell the difference between an observation and an inference while protecting the chain of custody.
- 1Open the Unit 1.1 task in your PLTW shell so you know what scene evidence is graded.
- 2Sketch the assigned scene to scale and label fixed reference points before touching anything.
- 3Record each piece of evidence in an evidence log with a number, description, and location.
- 4Mount a trace evidence sample (hair or fiber) and observe it under low and high power on the microscope.
- 5For three observations you record, write a matching inference and explain how they differ.
- 6Sign and date your evidence log to model chain of custody and note your control sample.
- • You can produce a labeled scene sketch and a complete evidence log.
- • You can distinguish an observation from an inference in writing.
- • You can explain why chain of custody and a control sample protect evidence.
Daily lessons this week
Open any day for its full lesson, the work due that day, and guided notes.
Written CER (3-5 sentences) taking a side on whether investigators should disturb a scene to collect evidence, with a chain-of-custody reference in the reasoning.
Exit ticket: write the four documentation steps in correct sequence and list three required fields in a chain-of-custody record.
Team scene packet: one photo with scale marker, scaled sketch with orientation, completed evidence log, microscopy sketch at two magnifications, and one contamination risk noted.
CER arguing what the trace evidence suggests about the scene, using Wednesday's microscopy observations as evidence and acknowledging at least one limitation.
Complete scene evidence packet: scene photos with scale, labeled sketch, signed evidence log, microscopy sketches at two magnifications, Thursday CER, and completed self-assessment form.
Quick intro to the week
- A scene only tells the truth if you document it before you disturb it, so today you slow down and record like a professional.
- Today's goal: build a clean evidence log and use the microscope to turn trace evidence into reliable data.
- Monday's bioethics debate frames the unit: when does collecting biometric data at a scene cross the line into invading privacy?
- Your graded scene sketch and evidence log are submitted in the PLTW course shell.
Your PLTW coursework this week
Do this: Advance the PLTW PBS Unit 1.1 benchmark by documenting a scene and logging trace evidence in the online course shell.
- • Chain of custody is the documented record of who handled evidence and when.
- • An observation is what you sense directly, while an inference is a conclusion drawn from it.
- • A control sample gives a known comparison for trace evidence.
- • Create a scaled scene sketch and a numbered evidence log.
- • Operate a compound microscope to examine trace evidence.
📋 PLTW evidence due Friday: completed Unit 1.1 scene sketch and evidence log with chain-of-custody documentation.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction.
This week's PLTW tracker
Your week at a glance. Check off each deliverable as you finish it, then submit so Mr. Mendoza can see how the class is pacing.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
| Day | Date | Focus | Key deliverable |
|---|---|---|---|
| Monday | Mon, Aug 31 | Ethics of the scene | Written CER (3-5 sentences) taking a side on whether investigators should disturb a scene to collect evidence, with a chain-of-custody reference in the reasoning. |
| Tuesday | Tue, Sep 1 | Documentation and custody | Exit ticket: write the four documentation steps in correct sequence and list three required fields in a chain-of-custody record. |
| Wednesday | Wed, Sep 2 | Scene documentation lab | Team scene packet: one photo with scale marker, scaled sketch with orientation, completed evidence log, microscopy sketch at two magnifications, and one contamination risk noted. |
| Thursday | Thu, Sep 3 | Analyze trace evidence | CER arguing what the trace evidence suggests about the scene, using Wednesday's microscopy observations as evidence and acknowledging at least one limitation. |
| Friday | Fri, Sep 4 | Submit scene evidence | Complete scene evidence packet: scene photos with scale, labeled sketch, signed evidence log, microscopy sketches at two magnifications, Thursday CER, and completed self-assessment form. |
- M: Philosophy for Kids / John Carroll bioethical debate
- T: teacher background notes + PLTW launch task
- W: lab / data or model work
- Th: analysis / CER or design revision
- F: submit tracker + weekly evidence
Due by week's end: Scene sketch/evidence log.
Lab day — what to bring & watch
This explainer accompanies the PLTW lab protocol — watch it before lab.
What to do when absent
Most days, this class is your PLTW coursework — and PLTW is online and individual. So being out usually just means doing exactly what we did in class, from home.
Open Schoology (CMSD) and keep goingHow to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
You can't do those from home — do this instead: Teacher-posted data/model packet, same objective. Supplemental: Khan: scientific method; HHMI/forensics teacher-approved evidence clips if used.
Class still runs. A substitute will post today's plan — complete the online activity above; it's built to be self-guided. Need the concept taught without a teacher? Use this authoritative explainer:
Khan Academy: using the microscope (Cell biology)Vocabulary
Virtual resources
Resources & readings
Hand-picked materials for this lesson. Class file items open the document directly; the rest are vetted readings and interactives from other biomedical programs.
Standards this week
WebXam practice
Drop your Week 2 here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
Upload a project