Good example. But let's suppose you've never seen any rectangle that
wasn't square. You've learned that you only need to measure one side
(with a Bird side-meter, undoubtedly) in order to determine the area.
Works fine. Always has. You swear up and down that the area of a
rectangular figure is always the square of one side. Then someone gives
you a rectangle. Worse yet, they claim there's something called a
rectangle, which you've never seen.

It's been really interesting to see how the various participants in this
discussion react to this new concept.

Roy Lewallen, W7EL

Richard Harrison wrote:
Keith wrote:
"Scientists are usually interested in producing models which will allow
them to predict the behaviour of the real world.

True. Models must be adjusted to reality, not the other way around. But,
once the model is verified it becomes useful.

You don`t have to measure the area of a rectangle with a planimeter once
you know that area is the product of the length and width of the
rectangle.

Best regards, Richard Harrison, KB5WZI