The human physics laboratory

Another great lecture at WIT this week was a public lecture on the physics of the human body. (The lecture was presented as the annual Tyndall lecture of the Institute of Physics and also as part of Engineering Week at WIT by CALMAST, see post below).

The lecture was given by Dr Kevin McGuigan, Senior Lecturer in physics at the Royal College of Surgeons of Ireland. Kevin is well-known for his successful research into the solar disinfection of drinking water, but he clearly has a second talent as a natural communicator of science.

The theme of the talk was that if you consider almost any important principle in physics, you will find a great example of its application in the human body. There were dozens of intriuging examples of this, here are just a few:

– Discussing friction, Kevin described the role of saliva in overcoming friction in indigestion. The students weren’t particularly interested until he gave a superb demonstration of the effect by getting two hapless volunteers to stuff themselves quickly with cream crackers without water!

– On Newton’s second law, the speaker explained the concept of impulse, showing clips of the effect on the neck/head of the driver of a car brought to rest from high speed, or struck from behind. He then explained the importance of both the crumple zone and air bags.

– A quick overview of the physics of rotational motion in liquids led to a discussion of the role of fluid in the ear. Kevin then gave a demonstration of the role of this liquid in balance by rotating a hapless volunteer in a chair 10 times!

The human laboratory: IoP Tyndall lecture

The speaker also discussed Bernouille’s equation, discussing what happens during an aneurysm as example. However, I suspect the students enjoyed another example of Bernouille’s equation most – ‘The physics of farts’. Here Kevin gave each member of the audience two sheets of paper and got them to observe what happens when you place them close to the mouth and blow (it behaves like a shutter opening and closing due to the difference in air pressure on the sides of each sheet). He then explained this as the same process that happens as  boys (only boys?)  attempt to release compressed air from their posteriors without making a sound, usually with a resulting brmmmmmpt!!

Another fine example was a demonstration of how sweat cools the body, using the latent heat of vapourization.

All in all, this was a super example of an outreach lecture that got a fantastic reception from a packed auditorium of students and schoolkids. I had to leave early, but I found myself frantically taking note of examples for next year’s 1st science class!

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