File:Chair-engineerguy.ogv

Bill asks the question "Why a chair?" ... the answer reveals the human aspects of engineering design.

Transcript: A chair highlights how much engineering design depends on culture constraints. Chairs come in a huge number of styles and sizes.

Now a chair seems like a natural response to how we bend at our ankles, and our knees, and our hips, but it isn't at all.

Social, not genetic or anatomical forces gave birth to the chair. Humans don't need chairs: In fact, people raised in a society that squats are perfectly comfortable.

In fact, it's perfectly natural for children to sit on the ground, until the chair conditions it right out of them, and then it hurts to get up!

So, why a chair?

Although around since ancient times, the chair was never a essential part of the household. In Rome, for example, the bed was the all-purpose piece of furniture. A Roman would eat, read, and write on their beds.

The chair made progress for many centuries, but took a few back in the 7th and 8th centuries: Arab conquerors, a people with no steady wood supply, replaced the chair-level ways of the pre-Islamic Middle East with floor-level seating.

In the 19th century the Industrial Revolution propelled the chair into our homes. Partly because of mass production, but also because the nature of work itself changed. Assembly line and office workers were more likely to be seated than those in agricultural.

And it looks like chairs are now unstoppable. Chairs are locked into our architecture: Windows are now set such that we have to be 18 inches off the ground.

And the chair is firmly ingrained in our culture. University professors hold chairs, and we have chairmen, chairwomen, and chairpeople, and as an outgrowth we county seats, district seats, and seats on the stock exchange.