(simulated) blood stains
- 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
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on Wednesday, April 20th, 2005 at 20/04/05 and is filed under Maths.
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