I will tell you people a story today. Well not a whole story, just an incident.
So the evil man got in the way of The Bride. And his head fell in one neat stroke of her katana. If I make this into a movie there are two ways I can go from here. One is the gory japanese style ala Ichi the Killer, of which Quentin Tarantino is quite a follower. Another is the regular action film, where the director has chosen the genre of the film as non-gory, decides to just let the blood flow slowly. What do you think will happen to the evil man?
We will discuss scientifically what should happen lest the above incident actually happens outside a studio.
Why? Why oh why? What is the need of such a discussion do you ask. Becaue there is a difference between the science questions we grew up solving in school and that we encounter in our day to day life. In the school questions, all the variables are defined. You already know what is known and what you have to find out. In the real world the exact problem is not very evident. It is not even evident that there’s a scientific question around. There are prejudices, supersition, common sense and a lot of other such words floating around. So if you know what the exact problem is, the solution is just elementary school standard.
The above diagram is pretty self evident. And apart from the normal pressure head, there is a lot of lose in pressure due to kinks and bends in the pipe.
So when someone is beheaded, the pressure at which the blood will spurt out is =
P = (density of blood) X (gravity) X (height of head) + (a considerable lose factor)
Since our arteries are pretty branched the lose factor will be quite high.
Conclusion is that the blood will spurt for a moment of time to a height close to the top of the head (at least). The at least is because extraneous factors like the air resistance, the lose factor, etc. After the initial moment of spurt since the system is now not closed (less amount of blood in the system), the speed of the splurting blood will ebb and then change to a flow.