BOYS practicing with air rifles like to shoot at targets that will reward them with action when hit. When the target shown is struck, it will leap into the air with a loud snap. Target holder is soldered to trigger of mouse trap.

Build your own LASER! (Nov, 1964)

PS Builds a LASER …and so can you

The incredible ruby ray is the hottest scientific discovery of the decade, but practical uses are still scarce. Here’s your chance to join the search

-June, 1960: Dr. T.H. Maiman, of the Hughes Aircraft Co., reports the development of the first successful ruby laser.
—November, 1964: Popular Science publishes plans for the first do-it-yourself ruby laser.

By Ronald M. Benrey

IT MAY sound like science fiction— but it’s really science fact: You can build a working ruby laser. It could be the most challenging—and rewarding— home-workshop project that you have ever tackled.

A ruby laser is a source of coherent light. All of the light waves in the pencil-thin, bright-red ruby laser beam are in phase—or in step—with each other. This extraordinary property of the laser beam—shared by no other light source—has spurred a world-wide search for practical uses.

Ordinary light sources—a light bulb, for example—generate incoherent light; the light waves are out of phase with each other.

Drop a pebble into a still pond, and the waves ripple out smoothly in all directions. This represents a single light wave from a light source. All light sources produce more than a single wave, however.

They act as if you dropped a handful of pebbles at once: You get a jumbled clutter of waves one on top of another. This clutter of waves is analogous to incoherent light.

Suppose, though, you dropped your handful of pebbles one pebble at a time, each in exactly the same spot in the pond. The waves would continuously radiate from that point. All of the wave crests would be in phase. This is coherent radiation.

A ruby laser generates a coherent light beam by a similar process. Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Inside the ruby laser rod—heart of the ruby laser—excited atoms are stimulated to emit light waves in phase with each other.

Light Harpoon Gun Spears Fish and Frogs (Jun, 1952)

Light Harpoon Gun Spears Fish and Frogs

THIS efficient weapon operates on the same principle as the harpoon guns used in whaling in that it has a line uncoiling from a tank with which to retrieve the harpoon as well as the prey. Appearance and size (Fig. 3) are similar to a conventional gun with the exception of the tank for the line. The “barrel” (Fig. 1) consists of a length of cold-rolled steel channel secured to stock with 3 countersunk screws, and has a guide near “muzzle” with a-groove for harpoon shaft to raise one of the barbs above bottom of channel. Well or tank for line is one end of a 1 lb. fruit can, edges filed smooth and painted brown. Fit end of line with a ball or block; before firing wedge line in one of the forks as illustrated. To recoil line lift out end and, beginning at that end, wrap line loosely around your hand and replace in tank.

Power It with a PULSE JET (Jun, 1952)

Power It with a PULSE JET

THIS model plane project uses what may be the smallest successful pulse-jet engine ever built. It was developed after scores of experiments and the building of a dozen test models by Hiram Sibley, Jr., a California guided-missile engineer.

Print Photographs in COLOR on METAL Gifts (Jan, 1935)

Print Photographs in COLOR on METAL Gifts

YOU can inject a personal note into your Christmas gifts this year by placing on them photographs of yourself, of friends or of scenes you have snapped with your camera. Any smooth surface can be treated in this way, including metal, wood, glass or composition. The pictures are permanent, can be made in any color, and have the shiny, glass-like appearance of glazed enamel.

Build Your Own Geiger-Gun (Jul, 1957)

Remember, EVERYONE should have a Geiger counter! No exceptions. If you don’t build one now, you’re going to feel mighty stupid when you’re trying to evade the radioactive hot spots in post-apocalyptic America.


Ultra-simple counter useful on camping trips or in CD survival kit

EVERYONE, prospector or not, should have a Geiger counter. Many wise householders are assembling survival kits of food, bandages, and water. By adding this handy, inexpensive radiation detector, you can provide your family with a means of detection of contaminated material in the event of atomic warfare. Simple as the counter may be, it will detect radiation as feeble as that given off by a watch dial—or it could make you rich by locating a uranium ore vein.

Divine Strobotron (Jul, 1957)

Why divine? Well if you look at the diagram on the third page you can clearly see the image of the Flying Spaghetti Monster. Obviously the designer has been touched by his noodly appendage.

The next steps for me are an ebay listing, followed by the inevitable pictures of me in a Golden Palace Casino T-shirt and hat.


High Speed Stroboscope Freezes Motion


WOULD YOU LIKE to examine the contortions of your high-speed circular saw, drill or handsaw under conditions that seem to slow it down to a crawl ? Any repetitive movement, whether rotary or reciprocating, can be viewed as though the moving body were at rest or in very lazy motion—under the flashing illumination of this wide-range “Varistrobe” (variable flash-rate stroboscope).

Junior Cadet Space Helmet (Aug, 1962)

Wow, this looks like it’s harder to make than than the street legal kart.

Junior Cadet Space Helmet

As any budding young astronaut will tell you, his most important piece of equipment is a realistic helmet with light, radio, oxygen tanks, and plenty of colorful armor.

WETHER they’re solving re-entry problems on the living room banister or stalking Martians in the orchard, junior spacemen need plenty of imagination-inspiring equipment. So vital a piece as the helmet should be built at home where the astronaut can help and be sure the construction meets space-age requirements.

Remote-Control STATION WAGON (Aug, 1949)

Remote-Control STATION WAGON

A 7-1/2 inch scale model of the Jeep Station Wagon. Powered with a miniature electric motor, you can “drive” it yourself.

By Douglas Roffe

A flick of the switch, the lights go on and this realistic little station wagon starts to roll! A flick of the switch and it’ll back up! A twist of the wrist and you can steer it to the left or the right!

Powered with a miniature electric motor driven by batteries housed in a flashlight case, this remote control model car is as agile as the real Jeep Station Wagon after which it was patterned. Actually, the control system is very simple. One end of a flexible cable is connected to the steering mechanism on the car while the other end is attached to the flashlight case. By twisting the case the front wheels can be turned. Two wires extending from the batteries in the case are taped to the flexible cable and are connected to the electric motor which drives one rear wheel of the car.

Build Your Own Street Legal Kart (May, 1962)

Well, it was apparently street legal in 1962 at least.

In case you had any concerns about reliability; read about these guys driving this kart around the world.


You don’t need a trailer or a station wagon to haul this kart to a track you can drive it there on public roads!

By R. J. Capotosto

DRIVING a kart is a real thrill. Seated on a low-slung frame only inches from the ground, you feel as if you’re doing 80 mph when you’re doing 20. Yet it’s surprisingly safe. The low center of gravity and a width two-thirds the length make it almost impossible to flip a kart in a tight turn. Just about everyone who tries a kart gets the urge to own one—and if you’ve got that urge, you get a bonus in building the MI Highway Kart.

Since karts are generally driven on special tracks, it is not necessary to register them. However, transporting a kart is often a problem. It can be hauled in a station wagon—if you own a wagon—or it can be towed on a trailer. Either way, the lugging can be quite a nuisance. With this in mind, our model was designed so that registration could be obtained, making it possible to drive the kart to its destination on public roads.