Materials List: Bone Crusher

Each group needs:

  • 1 small animal bone, such as from a cat, turkey or chicken; purchase a turkey or chicken from a grocery store or butcher and remove the bones, or purchase a cat for anatomy dissection and remove the bones, or purchase a cat skeleton from
  • access to a scale, to measure bone mass
  • access to water, graduated containers and a sink, to measure bone volume by water displacement
  • (optional) calculators
  • computers or iPads with Internet access for student research, ideally one per group
  • poster-making supplies or PowerPoint® software, to create a class presentation
  • Bone Crusher Fracture Worksheet, one per group
  • Bone Crusher Design Worksheet, one per student

To share with the entire class:

  • tension-compression machine and a video camera to record bone fracture testing; see the note below for options
  • safety glasses 

Options for tension-compression machines:

  1. Arrange to use a tension-compression machine, such as a Tinius Olsen universal testing machine, at a local university. Contact the mechanical engineering department first, then the civil engineering department, requesting access to a tension-compression machine. Depending on the machine size, it can be transported to your classroom, or take the class to the university. If a machine is not available for classroom use, arrange for someone at the university to fracture the bones while students watch live via Skype or FaceTime.
  2. Use the method described in the Sticks and Stones Will Break That Bone! activity. To do this, duct tape a bone so it spans the gap between two tabletops; from the middle of the bone, hang an S-hook connected to a length of chain or rope holding a bucket by its handle. Add weights or sand into the bucket until the bone breaks. After a fracture occurs, measure the weighted bucket. Most chicken bones are capable of holding 40-50 pounds (18-23 kg). Some bones require a large amount of weight to fracture, close to 200 pounds (90 kg).
    A photograph shows a long, whitish bone held vertically at each end by the pincher grips of a machine.
    A tension-compression machine applies force to break a cat femur.
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