The magazine doesn’t show all of the construction details, but if you want to be accused of Russian meddling in the science fair, here’s the project for you. For the young Soviet comrade wishing to take home the blue ribbon in the oblast science fair, the November 1970 issue of Юный техник (Young Technician) magazine gave enough information to build a fax machine. Apparently, it was called a “phototelegraph-integrator”, since that is the title shown here.

Both of the drums are spinning at exactly the same speed.  A scanner is moving across one of them, and a printing element, such as a pen, is moving across the other one, at exactly the same speed.  One of the machines scans a picture of the word Mir (peace), and this is transmitted to the printer, which makes an exact facsimile.

The bright American student can also build a device that can transmit pictures through a wire. The key is to have two drums that are spinning at exactly the same speed. The easy way to accomplish this, for demonstration purposes, is to simply have both of them revolving together on the same shaft. Both of them need to have something that moves along the drum at exactly the same speed. The easy way to do this, for demonstration purposes, is to have the sending and receiving elements connected together with a shaft.

One of those elements needs to have a method to detect the picture. In a fax machine, that’s done with light. But an easy way to do it, for demonstration purposes, is to create the image using aluminum foil. Then, the sensor can be nothing more than a piece of wire that comes into contact with the foil.

This wire is hooked to a circuit which operates a solenoid. The solenoid raises and lowers a pen which comes into contact with the other drum. Whenever the wire on the sending drum comes into contact with the foil, the circuit is closed, and the pen starts drawing on the other drum.

Turn the drum while slowly moving the two sensors. The result will be a drawing exactly the same shape as the piece of foil.

The crude drawing below shows the general idea. An advanced student should be able to work out the invariable bugs and build their own fax machine. When you take home the blue ribbon, the other students will probably accuse you of winning due to Russian meddling. When they do, point out that there was nothing in the rules prohibiting it.

This young woman undoubtedly took home the blue ribbon in the 1960 science fair. And she certainly earned herself considerable street cred as a mad scientist by putting together this Jacob’s ladder, by carefully following the plans in the November 1960 issue of Electronics Illustrated.

As revealed by the schematic diagram below, the circuit is simplicity itself. It simply takes normal household current and runs it into a transformer which steps it up to 12,000 volts, which is fed into two electrodes. One way or another, there is going to be an arc between the two conductors. It will follow the path of least resistance, and thus starts out at the bottom, where the two metal rods are closest together.

The arc heats the air right above it, which ionizes the air. The ionized air thus becomes the new path of least resistance, and the arc moves upward. The process repeats until it reaches the top, at which point a new arc forms at the bottom.

The critical component, of course, is the high voltage transformer. In 1960, it was available in the form of a neon light transformer, for $12 plus shipping. Of course, neon signs still exist, and you can buy the transformers on Amazon.  This modern replacement is rated at “only” 10,000 volts, but it seems like that should be sufficient.

The 1960 article includes a number of important safety features. First of all, the electrodes are safely behind a sheet of 1/32″ clear acetate. This also appears to be available on Amazon.

And the choice of switch ensures that the device isn’t turned on accidentally. The power switch is a momentary switch, meaning that when you let go of the switch, it turns off. It’s a SPDT switch, meaning that when it’s off, another contact is energized. This is wired to a green pilot light that indicates that the device is plugged in. The switch has a safety cover, meaning that one needs to consciously lift the cover to flip the switch.

The article begins by saying that “if the directions given in this article are followed to the letter, there is no danger of shock. Don’t take short-cuts or omit the built-in safety features of this model; it is poor economy to leave out relatively inexpensive components that might prevent a nasty shock.”

These days, when one reads safety warnings, there’s a tendency to ignore them. But in 1960, when a warning like this was included, it’s because the activity in question was, indeed, dangerous, and you really needed to be careful. So I believe this project is suitable for mature students, working under the supervision of a competent adult. But this contraption is potentially lethal, and great care must be taken in its construction and use.  In 2016, a Michigan teen was killed trying to build one, and we don’t want any of our readers to suffer the same fate.  So please be careful.

If Junior is looking for a spectacular science fair project that can be built at little expense, but still uses a slightly dangerous chemical, he can’t go wrong building this real submarine, according to plans contained in the August 1940 issue of Popular Science.

When released in the local pond, the submarine repeatedly submerges and surfaces, all the time moving forward in the water. The secret of all of this is a small amount of calcium carbide, the same chemical used in old-fashioned miner’s lamps. When the chemical is exposed to water, it generates a high pressure gas, which is used to propel the vessel and provide buoyancy. The chemical is readily available at Amazon, and probably at your friendly local hardware store.

School will eventually reopen, so your young submariners can take advantage of their summer vacation to build and test the craft, which can be made out of scraps of sheet metal and tin cans. Soldering is required, but kids naturally enjoy working with molten lead. When school reopens and the science fair is on, the submarine can be used for a variety of scientific experiments involving buoyancy, propulsion, or chemical reactions. The teacher has probably seen old movies with miners wearing headlamps, but this will probably be their first exposure to the actual chemical used. A blue ribbon is almost guaranteed.

The young man shown here is probably getting ready to collect his first Social Security check, but fifty years ago, he undoubtedly took home the blue ribbon at the 1970 Science Fair. His project was shown in the August-September 1970 issue of Science and Electronics. According to the magazine, the project would show off knowledge and understanding, but would also require dexterity with tools.

The project was a moving-coil ammeter, not unlike a commercially made meter movement. While the magazine didn’t use the moniker, this type of meter is also commonly known as a d’Arsonval meter movement, after Jacques-Arsène d’Arsonval. For less advanced students, the article referred back to construction articles for some more primitive meters, such as the hot-wire ammeter we previously profiled. Most of the meter’s mechanical parts were made of wood, so the project required some expertise in the wood shop. The form for the moving coil was made with balsa wood, whose light weight ensured a sensitive movement.

The finished product could be accurately calibrated by using a commercial VOM, a battery, and a potentiometer. Current readings were noted on the commercial meter, and then marked on the face of the homemade meter.

According to the article, if the builder used reasonable care and followed instructions, they would be assured of a good grade and congratulations from friends and teachers.  And fifty years later, there’s no reason to think the result would be any different.

For the young scientist who wants to outsmart the science teacher, here’s an excellent science fair project that duplicates the work of American physicist Henry Rowland.

Your teacher undoubtedly knows that a an electrical current generates a magnetic field. But what your teacher probably doesn’t know is that a moving charge of static electricity also generates a magnetic field. This can be demonstrated from this experiment in the July 1940 issue of Popular Science.

To do the experiment, you set up an electric motor as shown here. You attach a disk of hard rubber, which you electrify by rubbing it with a woolen cloth. (Instead of the rubber disk, you can use an old phonograph record. If you don’t know what that is, you can ask your grandparents, or read some of our posts about the history of the phonograph).

Once the disk is charged up, you turn on the motor. As soon as it starts spinning, a compass placed nearby will deflect, showing the presence of the magnetic field.