Drops


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These three drops below – considered to be dried water drops – are visible on Folien 1. They are only three of the five big drops defence expert Arie Zeelenberg looked at. The other two drops are covered by the left index finger print and are not clearly visible. Our investigation therefore mainly focused on these three drops.

It is important to note that a world renowned expert in fluid dynamics, Prof Deegan from the University of Michigan, by implication cautions that we (all of us) must be very careful to assume that these are water drops. We have absolutely no proof that they are indeed water drops. The experts all simply assumed that they were water drops. They could be saliva, sweat, water, etc. Without having this knowledge, it is impossible to draw conclusive findings. For the purpose of our investigation we investigated a most likely scenario of normal household water and a relatively clean conical shaped drinking glass.

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About these three drops we ask these questions:

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– Considering that when a drop impacts a surface its final shape depends to a large degree on the impact angle, is it realistic to expect that all three drops will have such similar shapes and sizes when each must have had a different impact angle because of the round curved surface, as illustrated in the graphic above?

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– Considering a ‘most likely scenario’ of drops colliding with an inclined vertical surface while on a downward trajectory, is it realistic to expect that all three drops will not show any signs of vertical distortion or slippage? (We must state we do not say it was indeed spatter on whatever surface, but Zeelenberg claimed spatter, and we are simply reviewing this claim.)

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– If you consider the difference in impact angles created by a combination of a round horizontal plane (sideways) and an inclined vertical plane (downward), drops would spread both sideways and down on impact – basically following the plane of the surface. This is now without considering the further possibility that they will most likely break up on impact. Leaving smaller random size and shape drops (see further down).

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We have found that, considering for the sake of the argument spatter is responsible for the three dried drops, that drops flying in on a vertical surface, will break up in smaller drops on impact, leaving random shapes and smaller size drops. Remaining bigger drops will run down. Drops flying in on a flat horizontal surface will slightly spread and then stabilize under surface tension, mostly into elliptic shaped drops (depending on the impact angle), staying close to the volume and size of the original spatter drop.

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– Considering the size of the drops (4.5 mm x 2.8 mm) and the likelihood of contact angle hysteresis under the influence of gravity, would these drops all have dried to have such symmetrical shapes on a vertical surface? We worked on the size of the middle drop (4.7 mm x 2.9 mm) and using theory and principles of fluid dynamics, we calculated the angle at which such a drop would start slipping on pure and clean glass, and found it to be at a 62 degrees tilt. We must remember that the drops did not only had to sit on a vertical surface, but on an inclined vertical surface (due to conical nature of the glass).

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However, due to impurities and even microscopic defects in the glass surface, it is possible to for a drop to stick to glass at angles greater than 62 degrees (which is is a theoretical value assuming perfectly pure water and clean glass). But when this happens the drop will definitely experience contact angle hysteresis and deform under gravity – resulting in uneven white rims (see below).

– Household water contains some salts and impurities. In a drop that clings to a vertical surface and experiences contact angle hysteresis (deformation under influence of gravity), there will be a higher concentration of these particles towards the bottom of the drop where the drop bulges. During evaporation they will form a white rim along the bottom of the drop. In a drop that lies on a horizontal flat surface, the particles will be evenly distributed and will be deposited evenly during the evaporation process, forming a white rim right all around the drop.

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When looking across all three drops it is clear that there is no indication of a consistent thicker deposition along the bottom of the drops. Please see the images below for what these drops should have looked like if they dried on a vertical surface. These images were taken by Zeelenberg after experimenting with water spatter on a vertical glass plate, showing the white rims towards the bottom of the drops. These photos clearly contradict his claim and shoots him in the foot badly.

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– About the two wet blotches on Folien 1: Was it correct to claim that the two wet drops are consistent with a drinking glass without considering the climatic conditions of the 16 and 17 March 2005, how long it would have taken the drops to dry, and if the drops were deposited before or after the discovery of the body?

In a nutshell our findings in terms of drying time are that the dry drops could have been deposited on either a drinking glass or a DVD case any time before the murder – even days before it – and it does not favour one object or the other. However, considering sizes, shapes, white rims and positions, we can with great confidence and on a scientific basis say that the “dry drops” are more consistent with a flat horizontal surface than a curved vertical glass surface.

Regarding the “wet drops”: Any drops of water deposited on either object before the murder would likely have been dry by the time of the discovery of the body, and any water drops deposited any time before the discovery of the body would likely have been dry by the time the dusting took place. It is more likely that the two wet drops were deposited on the substrate the morning of the 17th (e.g. by brow sweat, sneezing), shortly before dusting took place. Under these scenarios the presence of two wet drops on the substrate does not favour a drinking glass over a DVD cover.

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Above: A drinking glass and a DVD cover splashed with the same water in one event – by flicking wet fingers from about 1 m away. Note elliptic shape drops on the DVD cover and random and odd shape drops on the drinking glass.

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Above: More examples of elliptical drops on a DVD cover.

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Above: Our test drops as on-scale overlays on Folien 1’s drops.

Below are the drops – about 12 of them – of which Arie Zeelenberg told us absolutely nothing about. They were taken from different sized high resolution images of Folien 1 in a landscape positive view, top line to the top, cut corner to top right. Relevant scales are included.

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These drops are quite small – generally less than 2 mm – and in most likelihood arrived by spatter. We have at least one drop that show a definite upward flow (Drop 3) – and three elongated drops that are either as a result of flow or low impact angle drop spatter (Drops 1, 2 and 4). Drop 7 shows a double ring – indicating that something interfered with the natural evaporation process. If we argue that a drinking glass could have been turned upside down while drying, we must consider that the potential flow is also sideways. What is especially noticeable is the complete absence of gravity – there is no consistency between the drops that shows the impact on gravity – shape, alignment, contact line deposits, etc., either in an upward or downward direction.

Zeelenberg who favoured a glass, because his argument was that “the object must have been in the vicinity of water”, negates the fact that a DVD cover can also come into all sorts of contact with all sorts of drops. We do not even know that all of these drops are dried water drops. There is no way we can know this. See what happens when you open a Coke can, or take a bite from an apple. Or sneeze. Cleaning detergents, shaking wet hands, a dog shaking wet hair, rain. Even pressing a fork into a sizzling hot mushroom can lead to fluid squirts. Moving a dripping wet object, such as a cloth or condensed beer bottle, over the DVD cover. Often in households DVD’s are watched by groups of people in a social setting in the presence of food and drinks (containers with liquid). And then we must consider that a DVD cover travels around. It lies all over. It can lie on many angles, thus drops can lay and dry on many angles (which can be the reason for inconsistent and uneven rim deposits).

By the difference in sizes, shapes and alignments it appears as if the drops on Folien 1 may have been deposited at different times by different sources. A drinking glass is washed after every use removing remnants of older drops. A DVD cover is typically not cleaned that regularly and can hold older drop marks for longer.

What if there was a drop that was cut off in the process of the double lift? Thus, it sat on the substrate and the first lift cut the bottom part off, then the second lift lifted the remaining top part? Although we cannot say with absolute certainty, the drop shown below looks very much like such a drop. It most certainly has the shape of a drop and clearly a part of this shape was cut off. (Even if it is not a drop, any shape that is cut off like this can tell us something about the lifting process.)

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This cutting off of part of a drop will not be possible with the drinking glass scenario, as only one folien would have been used and it would have stuck over the top and bottom edges (see below). A drop would also not sit in this partial shape on the bottom edge of a glass. Due to capillary forces and gravity it would run and spread along the bottom edge of the glass and onto the surface and would therefore not have a straight cut off line. The bottom of the partial drop was clearly ripped off, it is not a stop-of-flow mark.

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Not convinced about the partial drop? What if there was a second one? Two of them? See here

The drops on Folien 1 tell us of a flat surface which would often, and maybe even mostly, be in a horizontal position. Not one single drop on Folien 1 conclusively tells us of a curved and vertical surface.


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