Yes folks, it's a plastic tube that you blow into and a little pointer moves along to register how hard you can blow ...so simple that nobody could possibly make it wrong, or could they? Notice how the graduated scale bunches up towards the far end ...it's called a logarithmic scale and properly reflects the exponentially increasing amount of force required to move the pointer. Think of it like throwing a ball ...to toss it a couple of yards requires almost no effort and to throw the same ball half the length of a football field requires much more force. The amazing thing is that this scale was changed by the manufacturer only recently ...read on.

This is how the peak flow meter's scale used to look ...notice how the graduations are all evenly spaced from one end to the other. The person who thought this was a great way to measure force needs a good kick up the arse. I wrote several emails to the manufacturers and they never did reply ...so I made a web page detailing what was wrong with the design and just waited for the search engines to pick up on it. Mysteriously, the company dropped the old linear scale eighteen months later. Whether I was wholly responsible for forcing them to change the design, I will never know ...but I was in there somewhere!