Blood Spatter Trigonometry

A moving droplet of blood will eventually hit a surface. At the initial instance of contact, the spherical droplet will be tangent to the intercepting surface. The type of spatter the blood droplet leaves on the surface strongly depends on its direction and speed (its vector).
In the diagram, the instance of contact is shown for the red spherical droplet. A Dandelin cone based on the vector approximates the elliptical spatter pattern the blood will leave behind. Note that the initial tangent point is one of the foci of the underlying ellipse. The speed and viscosity will further deform the elliptical pattern.
At a complex crime scene, a forensic scientist collects data on these elliptical spatter patterns, then uses trigonometry to calculate the vectors behind each spatter. The vectors lead back to a position in time for the former owner of each droplet.


  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.

Related Curriculum Standards

US Common Core State Standards, Mathematics

Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and
interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Step-by-Step Solutions »
Walk through homework problems one step at a time, with hints to help along the way.
Wolfram Problem Generator »
Unlimited random practice problems and answers with built-in step-by-step solutions. Practice online or make a printable study sheet.
Wolfram Language »
Knowledge-based programming for everyone.
Powered by Wolfram Mathematica © 2017 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+