Distance Fallen vs. Stain Diameter (Screencast)
Learners observe how a blood drop in flight continually accelerates and increases in velocity over time. As the drop falls, resistance accumulates. The increase in stain diameter relative to distance of a typical 50 ml drop of blood is represented here. This activity has audio content.
This screencast, we see how the shape of a stain defines the angle of impact. In general terms the more circular the stain, the more perpendicular will be the angle at which it struck the surface. The more elliptical the shape of the stain, the more acute the angle will be. With practice and experience, the analyst can recognize the general angle of impact based solely on the shape of the stain.