By Rod Cross, Physics Department, Sydney University. May 2007
Balcony falls are relatively common. The picture below is a photo of the glass panel below a balcony handrail taken soon after a woman fell over the handrail. Dust on the outside of the glass panel revealed an impression where the woman had pressed against the outside of the glass panel before falling to the ground. The photo is upright, shows the whole panel from the floor to the hand rail 1 m above the floor, and was taken at night looking out through the glass panel.
A white handrail is at the top of the photo. Balcony floor tiles and the balcony door are reflected in the glass. The floor tiles are actually in front of the glass panel and form the overexposed white patch at the bottom of the photo. Part of a wood chair is on the floor at the left of the photo. The most likely events that led to this pattern on the glass are shown in the stick figure diagrams below. The event was not clearly witnessed, although a male inside the apartment said he saw the woman go head first over the handrail. The police were not convinced since the image in the glass was upright. The woman was wearing a strapless dress.
The resulting patterns on the glass are sketched below:
In this case, the sequence of events responsible for the fall was determined by careful examination of the evidence left on the balcony itself. The woman hit the panel twice, first in an upside-down position (c) and then in position (e). Evidence from the trajectory of the fall was not required. The coffee bean or oval shape pattern was most likely formed by the dimple that develops at the top of the shoulder when the arm is stretched backward.
Further details of this and another falling fatality can be found in an article published in Journal of Forensic Sciences, 51, 93-99 (2006).