Let's consider the glaze on the meatloaf. Specifically, ketchup.
Putting the meatloaf away, I almost grabbed aluminum foil. That would've been a mistake, since it can actually react with the tomato-based glaze and dissolve the foil -- assuming the meatloaf is in a metal loaf pan.
The reason this happens is that it's forming a primitive battery between the dissimilar metals (pan and foil) and an electrolytic medium (acidic tomato paste). This is the same principle that Allessandro Volta used when he produced his first battery, eponymously called a voltaic pile.
His invention was inspired by the work of a contemporary, Luigi Galvani. They actually had marked disagreement about the nature of electricity. Volta saw it as a natural phenomenon while Galvani believed it to be biological, perhaps because of how he discovered and investigated it.
Galvani, of course, did his famous experiments with frogs that showed how the muscles of dead frogs could be induced to kick. This, eponymously named galvanism, is related to a the more subtle galvanic skin response that deals with changes in conductivity of human skin under different conditions.
The most famous application of galvanic skin response is as one of several measurements used in lie detectors. Perhaps a more proper term for this sort of lie detector is polygraph, which reflects the fact that it's using a variety of different inputs.
The polygraph, in its earliest incarnation, was the invention of one William Marston, quite an interesting individual. He invented something else which you've surely heard of: Wonder Woman.
This comic book character that later entered movies, cartoons, and everything else, was produced by William Marston. You'll also recall that she had a "lasso of truth"... a reference back to his interest in lie detectors, perhaps? (And that fact that she seemed to go around tying people up all the time... well, a reference to some other interests of his, perhaps?)
Regardless, it's undeniable that the Wonder Woman character has been successful, however, and established a strong female role. One rendition was the campy TV series featuring Lynda Carter. She also appeared as a guest on the Muppet Show with a Wonder Woman theme.
And that leads back to what we were watching with dinner recently. It was an earlier episode of the Muppet Show and it featured a rendition of Yes, We Have No Bananas. It was performed by Marvin Suggs and his All-Food Glee Club. (It's Jim Henson -- it doesn't have to make sense!)
One of the singing foods? A tomato.
It makes a joke about ketchup and we're back to our yummy start of this journey.