(simulated) blood stains

Simulated blood stain 25cm board height

  • recipe: 300ml of milk and three tablespoons of treacle – warm milk over electric hotplate in milk pan. Spoon treacle in and stir well.
  • looks lumpy but dries (in a few days) really convincingly
  • Students set up a dissection board or similar with some wall paper afixed – set the board at known angles
  • drop the simulated blood a number of times at each angle
  • replace the paper with a new sheet and set aside to dry (we used prep room shelves)
  • set board to a new angle and repeat
  • cover range from roughly 80 degrees to 10 degrees at 10 degree intervals
  • use length of board and height of end as acurate measure of angle rather than rely on a small plastic protractor
  • test the relationship angle = arcsin(width/length) for the elliptical stains
  • low angles – stains almost circular
  • high angles – stains take on secondary drop patterns
  • intermediate angles – angles estimated from blood stain shape within 2 or 3 degrees of actual angle but always overestimating…
  • see blood spatter pattern analysis in bodmas for references
  • Thanks to Paul S, Helite, Terry, Jo, Vicky, Louisa for research, recipes and focus on this one

Simulated blood stain 50cm board height

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