## Calculus in the tannery

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How do you calculate the surface area of an irregular figure? If it’s a cowskin, you can buy an Electronic Area Measuring Machine to find it for you! The LOTO/SOFT model, for example, features continuous measure modeling, only 20 millimeters between photoelectric elements, and output in m², dm², tenths of dm², quarters of a square foot, tenths of square foot, or square inches. Not the right model for you? Don’t worry, there are several more to choose from.

I’m not completely sure how these machines work, but I’m guessing from the pictures and descriptions that each photoelectric element measures the length of skin that passes under it. Then, using the fact that the sensors are 20mm apart (so Δx=20mm) the machine must use the Trapezoid Rule, Simpson’s Rule, or some other form of numeric integration to estimate the surface area. Hooray — calculus in action!

Thanks to Mary Louise for telling me about this last week. She saw it on the “Tannery” episode of Dirty Jobs.

### 2 Responses to “Calculus in the tannery”

1. Mattia Says:

Good morning,
I’m the web master of GER Elettronica, I saw that the link to our website is wrong. Can you please change it in:
LOTO/SOFT = http://www.gerelettronica.com/prodotti_caratteristiche.php/lang=en/id_prodotto=1013/prodotto=area-measuring-machine-syncro-lt300/id_categoria=359/categoria=tannery-machines

Please let me know when you’ll change it.
Thank you very much for your availability.

Best regards

2. Ξ Says:

I’ve fixed the links and emailed you — thanks for the update!