It’s a question that I am sure many of you have asked yourself. If that angry looking person over there decided to hit me over the head with a bottle, would it be better if it were finished or full? Well thankfully a research paper has the answer and contains my ‘Research Quote of the Week’!

“Fights are commonly carried out with fists, feet, furniture and drinking vessels”

So, why would you want to research this? Well, Dr Bolliger and his Switzerland based team wanted to see “if the amount of energy exceeds the energy necessary to inflict serious injuries to a victim”, with the goal of aiding forensic science.

Now, its difficult enough making a choice what to drink when in your local pub, let alone to think about its potential use for research/weaponry. The researchers selected Feldschösschen in half litre bottles, the reasons for this choice were not made clear in the article (Figure 1). It was a small study, with 10 bottles used (4 full and 6 empty).

The strength of the bottles was then tested using a drop-tower (apparatus in which weights are dropped onto materials to test their properties. The bottles were place on their sides and had a wooden board attached to them (to cause a more dispersed impact similar to what the cranium would experience) and soft clay used to represent the brain soft tissue (As seen in Figure 2). A 1 kg heavy steel ball was dropped from different heights (minimum 2 m, maximum 4 m) onto the bottles.

They observed that full beer bottles tolerated energies of up to 25 J, but burst at 30 J. Whereas, empty shattered at 40J. Again, it is worth pointing out that this is a small study. But, the results are interesting ( especially for those with alcohol induced anger issues) as it indicates that the bottles make a much more suitable “club” than the traditional UK pint glass (shatters at 1.7 J). But, why does this difference occur, and which bottle would hurt more to get hit by!?

There are two main theories as to why the difference occurs:

Beer is an almost “incompressible fluid” and even a slight deformation could lead to an increase of the pressure within the bottle and its destruction. As beer is carbonated. The gas pressure, and may assist in the destruction of the bottle.

And the ouch factor? Well, as the study looked at impacts on the bottle and not made by the bottle as little mathematical recalculation is required to calculate the amount of work needed to swing the bottle and its imapact force. The researchers conclude the following:

“full bottle will strike a target with almost 70% more energy than an empty bottle. In other words, it takes less muscle work to achieve a greater striking energy when fighting with a full bottle, even though lifting the bottle requires slightly more energy.”

In terms of damage to the skull electrohydraulic experiments using human cadaver heads had previously shown that the skull is fractured by 14.1 – 68.5 J depending on the area hit. Implying, that both full and empty bottles could fracture areas of the skull.

So, there we have it. If you are a bit weak and want to cause harm an enemy with a beer bottle, either will do the job. But, choose a full bottle for that extra force in your hit.

Bolliger, S., Ross, S., Oesterhelweg, L., Thali, M., & Kneubuehl, B. (2009). Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull? Journal of Forensic and Legal Medicine, 16 (3), 138-142 DOI: 10.1016/j.jflm.2008.07.013