Forensic Anthropology With 3D Printed Bones

I 3D printed anatomically accurate bones for an inquiry-driven forensic anthropology investigation in a high school elective class. See the attached student handout for project description, objective, and assessment criteria.

NGSS alignment:

DCI: HS-LS1.A, HS-ETS1.C

SEP: Planning & Carrying Out Investigations, Engaging in Argument from Evidence

CCC: Scale, Proportion, & Quantity

I 3D printed bones with bone-colored PLA filament ordered from Amazon.com. The 3D printing happened on a Creality Ender-3 Pro and a Creality CR-10.

I printed deer bones from scans made by Dr. Eric Bauer: https://sketchfab.com/ebauer4/models and human bones from scans made by Dr. Elizabeth Weissbrod: https://3d.nih.gov/users/eweissbrod.

I buried the bones with play sand inside plastic bins, both purchased from Home Depot. I provided the students with tools including brushes, bags, envelopes, and Sharpies purchased at Dollar Tree, as well as evidence markers, evidence labels, and rulers, from Carolina Biological Supply.

I chose models of bones from reputable databases and users (see supplies section).

• Human: 1 femur, 2 os coxae, 1 scapula, 1 clavicle, 2 vertebrae (Dr. Weissbrod scanned all of these bones from the same female subject. For my activity, these bones represented the remains of a missing female hiker.)
• Deer: 1 femur, 1 pelvis, 1 scapula, 1 sacrum, 2 vertebrae, 1 jaw

I challenged my students by giving them both human and deer bones to identify and analyze. Models are available of many other types of human bones and from other species.

I 3D printed the bones from bone-colored PLA filament. I used a Creality Ender-3 Pro and Creality CR-10 printer. The CR-10 has a larger print dimension, particularly in the z-axis, which was crucial for the human female femur, the largest and longest bone.

I printed all the bones in life-size. The prints took several hours each, even for the smallest bones. On a few occasions I could combine several bones into one printing job, which reduced the time slightly.

I put sets of 7 bones into 6x16x24 inch flat, plastic bins, either 7 human bones or 7 deer bones. This number of bones seemed like an appropriate variety without being overwhelming. I added about 0.25 cubic feet of play sand (half a bag) to each bin. This was enough sand to mostly bury sets of bones without the bins becoming too heavy. I ruffled the sand to remove digging marks.

Each bin went to one group of 2-4 students.

I explained the scenario to the entire class: these bone scatters were recently found at a state park, and the police are trying to match the bones to missing persons cases.

I instructed the students to break up into their lab groups, go to their lab stations, and observe and ask questions about the bones for a few minutes before doing anything with them. Then we reconvened as an entire class. The students shared their observations and questions, such as, "I saw 3 bones, and I think one of them was a leg bone" and "How many bones are there under the sand?"

After sharing observations and questions, I asked the students to brainstorm what we should do next as forensic investigators. We had already reviewed these kinds of skills in class. I wrote their ideas on the front whiteboard.

The students returned to their lab stations in groups. They excavated the bones, counted them, took photographs and measurements, and entered them into evidence.

After documenting the bones as evidence, the students began addressing the objective of the investigation: do the bones match any of the missing persons cases?

Very quickly students judged whether they were working with human or non-human bones (the deer jaw is a giveaway). Groups with deer bones sometimes figure out the species by luck, intuition, or prior knowledge. Probing questions like "What do some non-human bones look like on Google Images?" "What kinds of bones are likely to be found in a forested state park?" or "What animals do humans hunt or see as roadkill?" can lead to student realizations.

Groups with human bones have to judge, based on the number, type, and features of the bones, the likely number of humans represented and the sex of the person. I asked guiding questions such as "How many of each bone does a person typically have?" "Are the bones proportional to each other, indicating they could be from the same person?" "How are bones different between male and female sexes?".

After all groups have investigated and analyzed their bones, I brought the entire class back together. We decided together what information the report of the investigation should include, which I wrote on the front whiteboard.

I graded this activity as a formative and gave the students the option to work in groups on their report, as well as time in class. If a summative grade, I probably would have the students work individually, and if time is limited, the students could work on their reports outside class.

I was astonished during and after the investigation how much students learned about human anatomy from this activity, while also practicing forensic techniques. Students used advanced vocabulary like "clavicle" with ease and precisely described their reasoning to draw scientific conclusions. Having the 3D printed bones, as opposed to paper models or descriptions, was essential to this level of enthusiasm and engagement.

I designed this activity for 2 separate sets of bones (human, deer) but you can use as many or as few types as you like, do multiples of each, or mix and match the types of bones for an extra challenge. Make sure to adjust the premise of the activity if needed: I specifically told students about a missing female hiker, and I printed a set of 7 bones from a female human, which one group excavated, analyzed, and matched to solve the case.