Okay, they’re just strips of metal, but CJ says one of each and a grapefruit will get you at least a “C” at the science fair. The copper electrode is 100mm long x 18mm wide  x .8mm thick (3.94" x .7" x .041”). The zinc electrode is 4” long x 3/4” wide x .027” thick and stamped “ZN”. And both of them are awfully useful for crafters and jewelry makers, too.

If Madame Curie had owned this, she'd be alive today. (She'd be more than 140 years old, of course, but still….) Our Radex RD1503 digital radiation meter evaluates the ambient level of gamma radiation, and can detect objects polluted by beta active radioactive nuclides. It uses a Geiger counter to detect the amount of gamma radiation within 40 seconds. It indicates the ambient dose equivalent in µSv/hr (0.05 to 9.99) and the µRem/hr exposure dose rate on a scale of 0.1 to1.25. The values are displayed on a 1-3/4" x 1-1/8" LCD screen. The presence of each particle is indicated by a clicking sound, for quick identification of affected areas, and it has an audio alarm with 3 adjustable ranges. The unit measures 4" x 2-1/4" x 1" and comes with a detailed manual and technical certificate. Requires (2) "AAA" batteries. Made in Russia. CE.

This black plastic gear is 3-1/16" dia with (96) teeth at 32 pitch, 20-degree pressure angle. Center has a 9/16" ID bore with a 3/4" dia x 1/8" bushing on both sides. One side also has (3) 3/32" ID x 1/8" standoffs along with a 3/16" tooth along one edge. Source and function are unknown but you'll think of something.

In the universe of reed switches, we're assured that this one is quite snazzy. In a 1" x 9/16" x 3/8" housing with a  3/8" mounting wing with (2) 3/32" mounting holes. Trigger distance is approx 1" regardless of magnet strength. Comes with 20" tinned leads. Rated for 400mA at 24VDC. Normally open.

These LEDs are wired with an in-line diode on one leg so you can run them with either AC or DC. 24 volts works best (do not run them on 120V!) drawing 4mA. You'll get leads between 4" and 9" with quick-disconnect terminals. You pick yellow or red.

These pushbutton switches have (8) sets of SPDT contacts and measure 2-3/8" long (not counting the button) x 1" x 5/8". The contacts for both rows, starting at the pushbutton, are normally closed; common; and normally open with (4) sets in each row. When the pushbutton is engaged, the window at the front is green. We think these were used as buss switches. Made in the USA for ITT/Schadow.

This solderable perf board for the electronics hobbyist measure 1-1/2” x 1-3/4” x 1/16” or 3-1/4" x 2-1/2" x 1/16" with 1mm dia copper pads on one side with holes sized for component leads. Has 1/8" dia mounting holes on the corners.

Is it spring? Well, it’s a spring. This steel extension spring is technically a “short throttle return spring” and measures 2-1/4" long x 7/16", but it will be just as happy returning anything else if your throttle is already back where it belongs.

This small reversible DC motor from JEI runs on 3-6VDC. At 6V it draws 350mA no load and stalls at 1.9A. Spins approx 1000 rpm and approx half that at 3V. Great for science fairs, hobbies and any kind of project that needs spinning. Measures 1-3/16" long x 7/8" dia with a 1/4" x 1/16" shaft and tiny contacts for power that you'd best solder.

This float valve assembly has a 2-15/16" x 1-9/16" dia white, barrel-shaped plastic float on a 1" x 1-1/4" stainless steel arm, making it look like a float valve for a Lilliputian toilet tank. Arm is connected to a 1/4" ID check valve with a 1" long flattened shaft and cotter pin connector. Designed for a bottom mount.

Don't wait or it'll all be gone. You get (4) pieces, 11 feet each, of 18-2 wire, polarized, black with a white stripe and eminently discardable spade-push terminals on both ends. (That's under a nickel a foot, cowboy.) Lamp cord, speaker wire, pretty much anything you run juice to.

Another very small jumper. This jumper wire is only 3" long with brass screw terminals. The wire is 20 gauge stranded copper and the terminal are 3/16" OD, 1/8" ID.

Individual cases for 3–1/2” computer discs. The nice thing about these is that they are stiff enough to protect the disc but just flexible enough not to be brittle and break the way most “jewel” cases do. Red, blue, purple or gold, all are translucent enough to read interior labels. We pick your color.

Ten dozen, to be exact. Our package of 120 radial lead electrolytic capacitors comprises: (15) each of 1uF, 2.2uF, 4.7uF, 10uF, and 22uF at 50V, (15) each of 47uF and 100uF at 25V, and (5) each at 220uF, 470uF and 1000uF at 25V. From Velleman®.

That's what these nylon bushings were made for, but they're suitable for anything that could use a little bushing. Our middle-sized measures 15/16" dia x 15/32" thick with a 3/8" bore and a slight taper.

No tiskets, just gaskets. Our super-slick translucent white silicone ring gaskets measure 2-3/4" OD x 2" ID x .031" thick. Made by silicone elves in a hollow tree. In the USA.

These pillow block bearings have 13-gauge steel mounting straps, 4" long x 1-1/8" with 5/16" x 5/8" mounting slots, and a sintered iron ball unit measuring 1-11/16" dia with either a 5/8” ID or 1” ID brass sleeve. The 5/8” ID one has an oil cup on the top; the 1” dia version has a grease fitting in the same place.

Ten-packs of 2-pin breakouts (or terminal blocks) from telephone junction boxes, in black or gray with red and green leads that terminate in a modular plug. The breakouts measure 11/16" wide x 5/8" high x 3/4" deep. The screw terminals are 1-1/4" long and the modular plug jumper reaches about 2-3/8" when snapped into its clip.