Large and heavy coils of enamel-clad copper wire, which allow for tight, dense windings, are useful for demonstrating induced currents caused by a changing magnetic field. Students can spin magnets on a rubber band to produce enough electrical energy to light an LED. Not much, sure, but it’s still borderline magical.
Note that these hold up for a long time. Acquired in April of 1966 – just shy of six decades ago – and it’s still in regular use.
That $115.00 price marked on there? $1,171.89 in today’s dollars. Do you think we’ve recouped our investment?
When learning about the laws of Ohm and Kirchhoff, it helps to have some hands-on experimentation, wiring together batteries and resistors and tiny little incandescent bulbs. Try it, see what happens, measure your voltage and current. Simple enough, yet more satisfying and memorable than just drawing squiggles on paper.
Plus, you get to open and close the switch like a tiny Frederick Frankenstein! Just try to resist the urge to shout out “My Creation Lives!” too loudly.
Ah, the annual astronomy craters lab. Lots of sand, lots of color powder, a handful of marbles and ball bearings and slingshots. And a mess that’s really something to behold.
It’s definitely a “don’t wear your good clothes” sort of lab session.
What to do when a battery-powered device would function better with fewer batteries? In our case, a dead-simple DC motor that gives better results when operating at 4.5 V instead of 6 V – but the holder that completes the circuit is sized for four AA batteries.
The answer: a battery-shaped slug of aluminum, which happily conducts current, fits in the place of a functional battery, and has some adorable bright-yellow heat-shrink tubing to stand out! Mostly because bright colors are easier to identify when you drop something on the floor. Round things have a habit of rolling off of surfaces at inopportune times.
One of the key benefits of a 3D printer is the ability to create prototypes rapidly. Doesn’t quite fit? Adjust the model, re-slice, and set the new print to go. When you’re down to sub-millimeter tweaks with each iteration, it’s a relief to let the machine whir and ooze out the next version.
If at first you don’t succeed, try again and again and again and again…
If it still works, it stays in service. There’s always a bit of “what’s this?” and “what’s it do?” and “how do I make it do what it does?” when stumbling across old equipment, but that’s what we have physicists for.
Probably not an actual horseshoe magnet inside there.
Remember those days? Floppy disks and cassette tapes and VHS and all those different storage media using magnetic materials, which could be corrupted or unwritten with inadvertent exposure to strong magnetic fields.
For fun, see how many modern applications still use a stylized version of the 3.5″ floppy as a “save” icon. (As of scribbling this, Microsoft Excel does.)