Using Trigonometry on blood stains

This is the free element of a lesson which I used at the end of the Trig topic and only includes the PowerPoint with two worked examples. This *** DOES NOT INCLUDE*** the worksheet I later mention. This can be found as a paid resource with the presentation.

This lesson looks at the use of Trig when looking at blood that was been ‘flicked’ at a crime scene. I go through two worked examples and then there’s a worksheet which has them doing 11 calculations split over 3 questions.

There are two questions which get the students to use the numbers to prove their findings. The second question asks them to explain how the small angle means it must have been flicked away from the body at a greater force showing this was an attack and not an accident.

The third gets them to show how three sets of stains have a similar angle and another three have a similar angle. This then proves the victim was hit once while standing and again while they were lower down which then proves the case.

This lesson needs limited explanation and allows lots of time for the students to have a go. I have put a ruler on the bottom just to help you when students don’t have them. Most of them just ripped it off and used them.