This 10-piece set of 1" cubes is made to test density in the classroom, and by all means you should do that. Otherwise, how will the children ever understand density? But we like to just play with the cubes, to set them on a desk, or stack them, or line them up, or make shapes out of them, or just pick them up and marvel at their weight differences. You get perfect cubes of aluminum, steel, brass, copper, acrylic, oak, nylon, pine, poplar and PVC.

"WE DARE YOU!" by Vicki Cobb is a 322-page book for children, filled with over (300) scientific challenges and experiments that can be done with ordinary household stuff. A savvy adult could introduce kids to science by betting them their allowance money on the afore-mentioned challenges, including making square eggs without using a square chicken, writing with potatoes, blowing frozen soap bubbles, and a whole bunch more.

Little-bitty horseshoe magnet, for traditionalists. Just 1-1/4" across x 1" x 5/16" thick. Red-painted Alnico, with approx 2.9 lbs of pull (ignore the 2 lb on the label) it includes a little steel keeper for when it's not sticking to a tiny horse's foot.

If you make cool stuff, people will pass it on to your children’s children’s children and you won’t spend eternity as just an old picture on a lost thumb drive. We suggest: Making Inventive Wooden Toys, a 184-page paperback with plans for (33) toys, many of them ballistic, out of scrap wood and easily found hardware; or Making Poor Man’s Guitars, a 176-page paperback with detailed instructions for building string instruments out of cigar boxes, frying pans, tin cans, mailboxes and washtubs, with a beer-can microphone thrown in.

You win some, you lose some? No need to keep switching pens when you have this two-headed ball point pen with a black cartridge at one end and a red one at the other. Perfect for those hand-held profit and loss statements.

Ferrite ceramic magnets can be quite powerful and have excellent resistance to demagnetization. These rectangular ones are no exception. Add the power of surplus and we'll give you a bunch of these mighty-mites at an uber-bargain price. Measures 1-7/8" x 7/8" x 3/8" thick with a 3-lb pull. Perfect for mounting even big pix on the fridge.

This magnetic sheet isn't large enough to make a magnetic bed, but it's just right for making a bulletin board, hanging on to a rounded surface, or clinging to a car door with its glossy magnetic side. It's a flexible, very dark brown rubber-like material, easily cut with scissors. A 2-ft piece is cut for you from the 2-ft wide x .011" thick material.

Physics project alert! This robust puppy of a magnet has dual 6V coils and stands 4" high x 3-1/4" wide, not counting the side terminals. Each coil draws 2.4A at 6VDC, and is conservatively rated for 40 Newtons (approx 9 lbs) at that voltage. Can be wired in either parallel or series, and comes with a mounting hook. Works great with a 6-volt lantern battery.

Our grandmother used to tell us that all the time, and we might have learned something while we were out there if she’d given us The Kid’s Guide to Exploring Nature, this 120-page paperback from the Brooklyn Botanic Garden. Chock full of information, photos and illustrations for exploring nature in both the city (includes pigeon info!) and the countryside, and in all four seasons. They might stay out of your hair until supper.

Or want to teach kiddies to write like Dickens or draw like Michalengelo? Start with blank, staple-bound 28-page paperbacks with bright white, 80-lb paper stock pages and card-stock blank covers. You pick: the 7” x 8-1/2” books or the 8-1/2” x 11” book, both with un-ruled pages because when you're young, staying between the lines isn't the thing to do.

Sounds like a Portuguese percussion album, but it’s just an alnico bar magnet in a mount that lets it rotate freely to demonstrate the three-dimensional magnetic field. Ideal for experiments about forces between magnetic poles, fields around wire and coils, and the properties of fields produced by electric currents. Also handy as part of your ghost-hunting gear.

That's what you get with this tesla coil!! Brand new, commercial item, great for classroom demonstrations and experiments. The 50,000 volt capacity generator radiates high frequency energy through space... enough to light fluorescent tubes two feet away. It uses 115 VAC (60 Hz) with an electro-magnetically operated interrupter buzzer, high voltage capacitors, inductive coil transformer, and a monopolar high frequency transformer generator to do the trick. 11" high, with a 6" sq. x 2" high protective housing for the generator. Includes accessories and instruction booklet with 19 experiments. Pretty amazing. But please, this is not a toy and should be used only under adult supervision.

Wonderful little book jammed with elaborate colored drawings that tells the beginner a little about everything to do with a microscope. And all in a mere 48 pages! From data on the history and types of microscopes, to introductions and samples and how to prepare them, (from tissues and insects to crystals) to ideas for experiments and lists of simple equipment needs, and how to build them at home, this book is a veritable cornucopia of information. If you are thinking of getting a microscope, we strongly recommend "The World of the Microscope" as a great stimulus for the novice user. It won't answer heavy duty scientific questions. But it will keep the beginner busy, challenged and entertained for days and weeks! By Chris Oxlade and Corrine Stockley. Paperback, 7-3/4" x 9-3/4". One of the Usborne science and experiments series of books.

Genuine, original, accept-no-substitutes brand-name Sharpie®s for when you really mean it and want a permanent marker. You pick the fine point red or blue, or the blue with a 3/16” bullet tip.

So the poster is really brand new. The animals on it are (1) to (190) million years old, and if that doesn't qualify as pre-history, may we stumble over a glyptodon in the dark. Invicta Plastics Ltd. of Leicester, England, printed this 23" x 16-1/2" poster with a colorful diorama to promote their authentic scale models of prehistoric animals. A time line across the bottom lists dates and data for a dozen of them, from the plesiosaur to the woolly mammoth, and compares their sizes to that of a pair of five-year-old children. Post it on the fridge to spark supper discussions, or in the classroom as a source of extra-credit questions for science quizzes.

White chalk is fine but imagine the possibilities of a full palette of colors. Looks nice, right? Our box is (16) pieces of washable chalk at 3-1/8” long x 3/8” dia, and you’ll get (3) boxes, each with (2) pieces of green, purple, yellow, pink, hotter pink, blue, orange and white, which is a color too.

These mighty nice little ceramic disc magnets measure 18mm dia x 6.5mm thick, which in America, Burma and Liberia is 23/32" x 1/4", and for those of us still math-impaired, roughly a stack of (5) dimes. They have a 1/4-lb pull. No crafter should be without an enormous supply of these. Also note the physics-class-friendly bulk price.

These Kooties™ are impish little trademarked critters, and in this case they’re on the hardboard covers of these mini-notebooks. Measure 3-1/4” square, top-spiral bound with (71) sheets in each with little Kooties and Kuotes in the Korners. We’ll pick from the (7) assorted Kooties™ on the covers, but they’re all kute. Kinda.