My apologies to fellow posters who might think I had abandoned the work I was doing on this. I hope you won't be disappointed in what I've been busy working on (besides the RL stuff that always comes up). Because its been a while (12-21-2012) since my last post in this series, I probably should review the main point I was trying to make which led me to where I am.
Parts-1 through -4 are all on the first page of this thread. But basically, despite the coroners reference to the depressed fracture as being a roughly rectangular shaped displaced fragment of skull, I believe it is in fact oval shaped. I feel knowing this is essential to knowing what weapon was used to cause the head wound.
I became pretty convinced about all this back around August/September (2012). So in the back of my mind, I had this idea that I needed some way of demonstrating it. Then when I saw the Halloween decorations going up in the stores, it dawned on me what to use. I found just the right one, bought some modeling clay, and here is the result:
The cheap plastic skull I bought has a flattened backside (Im thinking the reason for this is to keep it from rolling around when put on a table as a Halloween decoration), which allows me to add a layer of modeling clay which will show how various sized and shaped objects cause pressure. Since it is smaller than a real skull, I measured it to get an approximate scale size.
(Paying attention to the calculations is not necessary for the post -- they're just here for anyone who likes to know the details.)
I used the following dimensions for an average 6-year-olds skull:
1) skull perimeter = ~21
2) skull avg. diameter = 6.65
3) skull height = 7
Corresponding measurements on the toy skull are:
1) 16
2) 5
3) 6
Calculations:
1) 16 / 21 = 0.7619
2) 5 / 6.65 = 0.7519
3) 6 / 7 = 0.8571
So based on the above, when I get to where Im using this model, Ill use 3/4 (0.75) as the scale, which is pretty easy to use in calculations and reasonably close to what I measured. I think the third ratio (skull height) is off from the others because of a lack of correct perspective in the mandibular area depicted in the skull (not to mention the fact that after all -- its just a cheap-
passed Halloween toy). I think if I had photo software that allowed me to overlay a picture of the toy with a photo of an actual human skull, the reason for this variance would be obvious. But for my purposes here, using three-quarters as the scale is sufficient. What I am hoping for anyway is to demonstrate what would cause the 1/2 x 1-3/4 oval-shaped hole.
I mentioned earlier that in Geometry, an oval is the resulting intersection of a sphere and a cylinder. So I believe that it was some type of cylindrical object that caused the depressed fracture in JonBenets skull. Since we know approximately the dimensions of that area, we should be able to at least narrow down the possible diameter of the cylinder, and then perhaps decide what might have caused it.
But before I try to find the correct size (diameter) of the cylinder, I should demonstrate the effect of a few other objects that have been considered as possible weapons so we can eliminate them from the discussion. Rather than have to form the clay over and over again on the skull (for which I have no mold), I used something I could easily and consistently shape the clay to in order to get a curvature approximately the same as a skull.
Fortunately for me, Mrs. otg doesnt read here. If she did, shed see from what Im about to show you that I used her stainless steel mixing bowls and other various kitchen devices, and Id be in the dog house.
(Shhhhhhhhhh..... Dont anyone tell her -- I dont need the grief.) This is one reason its taken me a while to get some of this done
(Mrs. otg doesnt leave the house much without me since shes been ill.).
I put together the following video showing how I did this and the impressions left in the compound curvature of the clay with various objects and speculated weapons. I know most of the people here are pretty smart, so it shouldnt take too much to get the idea by watching this how different shapes leave different impressions, and the impressions of even other shapes can then be almost predicted.
Here it is. If a picture is worth a thousand words, this should hopefully save me a lot of writing about what I found:
[ame="http://www.youtube.com/watch?v=pUwVZclrqkY"]Weapon Shapes - YouTube[/ame]
Despite going through all the other reasonable possibilities I could think of and that other posters have suggested, the cylinder is the only thing that causes a depression in the clay in the same shape as the depressed fracture in JonBenets skull. So I feel comfortable in saying that Ive confirmed the geometry and am confident that the weapon used was cylindrically shaped.
One more little demo (and one that anyone can easily recreate) to show in small scale the effect of a cylinder hitting a spherical object:
[ame="http://www.youtube.com/watch?v=YgQqsStqaNc"]Egg Demo - YouTube[/ame]
The purpose of the ice cream scoop was just to compare the effect of something spherical to a cylinder (in this case -- the handle of a wooden mixing spoon).
The next thing will be to narrow down as much as I can the diameter of the object that might have caused the depressed fracture, and then show how it caused the linear fracture as well.