1. Warm Up
Objective: Scientists will describe tool mark impressions by taking notes and analyzing tool mark impressions.
What is the topic?
What will you be doing?
Why is this important?
How will you know if you have done well?

2. Warm Up
Objective: Scientists will describe tool mark impressions by taking notes and analyzing tool mark impressions.
What is the topic? Tool mark impression evidence
What will you be doing? Taking notes, analyzing tool marks
Why is this important? Evidence; future career choice
How will you know if you have done well? Able to describe tool mark impression evidence; analyzed tool marks accurately

3. Tool Mark Evidence
Certain defects or patterns may be left on a tool when it is made or used, which can be used to find matches between evidence at a crime scene and tools or objects found at a suspect’s home.
Tool marks can be classified two ways:
Impressions – As a tool hits a softer surface, the shape of the tool and imperfections in its surface may be left behind as an impression.
Scratches – As a tool moves across a surface, it may leave ridges or striations behind.
NOTE: Some tool marks are a combination of both types.
Features to analyze:
Dimensions of the impression
Ridges or striation patterns
Defects, such as nicks and chips
Paint chips or metal shards left on a tool
Images: and

4. Tool Mark Impressions Activity
For each tool:
Choose a clay and tool.
Place the clay on the paper plate.
Carefully hit the clay. Draw and describe the impression left. Smooth out the clay.
Scratch the clay. Draw and describe the scratch left.
Smooth the clay between each tool.

5. Tool
Impression Picture/Description
Scratch Picture/Description
Hammer
Adjustable Wrench
Groove Joint Pliers
Long-Nose Pliers
Slotted Screwdriver
Phillips Screwdriver
(Bonus) Diagonal pliers

6. Analysis How can tool marks help investigators?
Today, you used clay to represent a softer surface. Would the tool mark impressions and scratches on a harder surface such as wood or metal be similar or very different? Explain your reasoning.

7. DonorsChoose Thank You Cards/Letters
Dear Jacob Leh,
Cleaning supplies, organizers, Kleenex, hand sanitizer
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New printer with ink, camera to make newsletter + copies
Or work on things you need to finish!