P+B: The Bacterial Guide to Maxwell's Equations p3

Just updating my dA - feel free to ignore this if you've already seen it on SJ!
First page: pnb.smackjeeves.com/comics/186…
Second page: pnb.smackjeeves.com/comics/190…
Source of this page at pnb.smackjeeves.com/comics/190…


The final equation... we explain the relationship between electric current and magnetic field... Also, try this demo out if you haven't before and if you can get hold of a wire, battery and compass. It's really neat. At least Hans Christian Oersted thought so...

I realise the second row might not be all that clear - what we're looking at is a close-up of the metal plates joined to the battery, as shown in the previous strip. The metal ions in the plates are shown as red spots, and the free electrons as blue dots. The current in the wire is the flow of charge carried by the electrons.

A big thank-you to Andy Yeomans for explaining to me in 1st year the content shown here. What is displacement current? The current that would flow between the plates of a capacitor if the capacitor weren't there, except it is so it doesn't. Genius.

For anyone who's wondering, the capacitors you get in camera flashes look like this (at least in the old days, dunno how much tech has changed since): en.wikipedia.org/wiki/File:Con… - the metal 'plates' are foil-thin, separated by insulating gunk rather than air, rolled up and packaged all nicely. Some applications, however, will use capacitors like this: upload.wikimedia.org/wikipedia… - you can see the metal plates separated by insulating ceramic in the things in the middle column of the picture.