[Physics] Why is unit of pressure (psi) used to determine things like bite force of an animal

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Whether in tv documentaries or journals, whenever they talk about an animal's bite force, it's measured in PSI anytime imperial units are used (ex: National Geographic, NIH Journal). Many even seem to highlight the fact that it's pounds per square inch.

But when it's used in SI unit context (ex: BBC Earth), it's written in Newtons, a measurement of force.

It seems to me that a force should be measured in a unit of force and not pressure. Additionally, pressure alone would seem to tell us nothing since area is never specified, thus unknown force.

So why is a unit of pressure so dominantly used to indicate an animal's force?

For example, this science daily shows the croc having a bite force of 3700lbs. But then other sources (along with every other web search) will say 3700psi. This National Geographic article even writes psi side by side with newtons as if it was pound-force.

Best Answer

"Bite force" is just one of many anachronism that pop up in science when you look for them. Physics and the other sciences haven't always been such sticklers for accurately naming phenomena, both because they didn't care about rigor as much and because they didn't know better. In this case, the problem isn't bad units, it's a bad name. It really should be called "bite pressure" since it is the pressure that the teeth exert on whatever it is the animal is biting.

Strong jaw muscles and well shaped jaw bones will increase the amount of force that can be exerted, while sharp teeth decrease the biting surface, creating large pressures. When trying to pierce, cut, or grind, pressure is the important factor, not force.

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