Category Archives: World War 2

Science Fair Ideas: Fun With a Homemade Galvanometer

Eighty years ago, there was a war going on, but that didn’t stop young scientists on the home front from conducting experiments with the items available. If Junior’s science fair project is due tomorrow, he can take a cue, and whip together a great project from these ideas in the December 1942 issue of Popular Science.

Both experiments involve a galvanometer, and the magazine presupposes that young scientists know how to make one, because the instructions merely state to use “your homemade galvanometer.” But in case Junior doesn’t know, it’s easy enough. You just take a compass (a toy one from the dollar store will work just fine) and wrap a few turns of wire around it. The smallest of electric currents will cause the compass to move. If there’s a little extra time before the science fair, we’ve previously shown how to make a deluxe galvanometer.

In the first experiment, shown above, Junior can demonstrate that water, contrary to popular opinion, is an insulator. It’s only when a little bit of salt is added to the water that it starts to conduct electricity, and the compass moves. To accentuate the effect, we recommend starting with distilled water. And don’t worry about not being able to find the old-fashioned dry cell batteries. These experiments will work just as well with modern alkaline D cells, especially if you purchase battery holders for them.

The second experiment, shown below, shows how to make a thermocouple. Two pieces of wire–copper and iron (or steel)–are twisted together. When the twisted wires are put into a flame of a candle, the dissimilar metals produce an electric current, as shown by a movement of the compass. And as we always remind parents about experiments involving flames, don’t forget to give Junior a box of matches!

As with many of our projects, Junior is almost guaranteed to take home the blue ribbon, and the teacher won’t have a clue that the project was put off until the last minute.

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1942 Expedient Chassis

The December 1942 issue of the British Practical Wireless carries this self-explanatory hint sent in to the magazine by one J.M. Firth of Beckenham. He noted that there was a great shortage of aluminum and sheet iron for making chasses for radios. Quite possibly to Mrs. Firth’s chagrin, he found a suitable replacement in the kitchen in the form of a tinplate baking tin. He noted that the pan would take solder easily.

Fashion Pointers for Winter Fuel Shortages

The young woman shown here is about to turn 100, and she’s probably thinking about the prospects for fuel shortages this winter. But she’s undaunted and prepared for them, because she’s been through it before.

In 1942, there were also fuel shortages brought on by the war. The radiator was turned down many places, but according to the November 16 issue of Life Magazine, this girl learned a few tricks for keeping warm from her grandmother. Today, she’s probably teaching her grandchildren and great grandchildren the same pointers. The secret to stay warm was then, and is now, quilted fabrics. This young woman is showing off her quilted rayon taffeta slacks, quilted booties, and a closely knit long-sleeved sweater.

After you have your winter wardrobe picked out, don’t forget to check our earlier post about other preparations for winter power outages.

While we don’t know the name of the model, the photographer was Walter Sanders. The German-born photographer emigrated to the U.S. after being hounded by the SS for non-Aryan activities. As an enemy alien, his cameras were initially confiscated shortly after Pearl Harbor, but he was soon back in business.

1942: Car Radios for Slow Driving

On this date 80 years ago, the November 7, 1942, issue of Radio Guide carried this ad for Motorola car radios. Production of civilian radios had ceased on April 22, 1942, but Motorola dealers still had prewar sets in stock.

We previously featured ideas for bringing the car radio inside. With gas being strictly rationed, the radio would do more good inside. But Motorola took another view: Since you had to drive slowly to conserve gas and rubber, the radio would make the slow drive more enjoyable.

But those prewar stocks wouldn’t last forever, so you were reminded to get yours before they were gone, because there would be no more for the duration.

Air Raid Alarm: 1942

We’ve previously shown (here and here) this air raid alarm that could be attached to a radio, the Model AR-101 Air Raid Alarm from National Union Radio Corp., 57 State Street, Newark, NJ. The simple device would activate a siren-like sound if the station to which it was tuned left the air, which would presumably be because an air raid was in progress.

Here, in this illustration from the November 1942 issue of Popular Mechanics, we see it in action. While Junior looks on, Mom gathers the flashlight and shovel that Dad will use in his duties as air raid warden.

1942 Home Master-Slave Clock System

Eighty years ago this month, the October 1942 issue of the British Practical Mechanics
noted that battery clocks were in great demand because of the war. In the event of a cut-off of the electric mains, householders would be without a means of keeping track of time, and the battery clock was a solution. As shown above, you could build a system of clocks for your house. The master clock could be anywhere in the house, and it could be wired to any number of “slave” clocks. Plans for the master clock had appeared in an earlier edition of the magazine, and complete blueprints were available for two shillings. Once the time was set on the master clock, all other clocks in the house would keep accurate time.

To build the slave clocks, “the first thing to obtain is an old clock.” Most of the innards were removed, leaving only the two cogs behind the face, controlling the minute and hour hands (or “fingers,” as the author called them). At that point comes the task of making a cog wheel with 60 teeth, which “requires some care, but it may be easily made” by cutting a sheet of steel or brass, and then filing out 60 teeth.

Once a minute, the mater clock would send a pulse, which would advance the long hand–er, finger–by one minute. The author reported that he powered his system by a battery tucked away, floating on a trickle charger, and that his had been in operation for a few years with no problems.

The 1942 clock is quite elegant. But of course, today it would be of little practical value, since the cost of an extremely accurate battery operated clock is close to zero, as shown below. But for the person who constructed the 1942 version, I’m sure there was a sense of pride that the modern version can’t deliver.

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First Flight From Aircraft Carrier, 1922

USS Langley. Wikipedia photo.

A hundred years ago today, October 17, 1922, marked the first time that an aircraft took off from a U.S. aircraft carrier, the USS Langley (CV-1). While aircraft had previously taken off from ships, this was the first time that a ship specifically designed for that purpose had been used. The ship had previously been a collier in World War 1, and had been newly converted. That first plane was piloted by Lt. Virgil C. Griffin.

The ship had served as a collier in World War I, and was converted to a seaplane tender prior to World War II, in which she also served. The ship was damaged in 1942 and scuttled.

Signal Corps Recruiting Ad, 1942

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Eighty years ago this month, the October 1942 issue of Radio News carried this ad announcing that the U.S. Army Signal Corps was open for direct enlistment. As long as they had not received notice of induction, young men ages 18 and 19 could sign up, as long as they were physically fit. And up through ages 45, men with some experience in the communications industry could enlist as long as they passed the physical exam.

The ad appears to be paid for by Hallicrafters, probably as a way of keeping their name before the public, despite not being able to sell their wares for the duration.

1942 2-1/2 Meter WERS Transceiver

Eighty years ago this month, the October 1942 issue of QST featured on its cover this transceiver for the 2-1/2 meter WERS band.

The set was designed by George Grammer, W1DF, and the operator shown here is John Huntoon, W1LVQ, later W1RW, who was then communications manager of the ARRL. Huntoon went on to become ARRL Secretary and General Manager.

The three-tube transceiver was typical of designs of that era, with a superregenerative receiver that could be put into service as a transmitter at the flip of a switch.

1942 Boy Scout Civil Defense Messenger

Eighty years ago this month, this unnamed Scout performing his civil defense duties is shown on the cover of Boys’ Life magazine, October 1942. His armband is the insignia of a civilian defense messenger, but all we know about him comes from his uniform, that he is that he’s a Patrol Leader of Troop 3 in Mt. Vernon. Unfortunately, there are dozens of towns named Mt. Vernon in the U.S., but his uniform doesn’t indicate the state.

This issue of the magazine talks about other Scouts engaged in defense related activities, but doesn’t specifically talk about the Scout on the cover. But the magazine gives an important clue, namely, the identity of the photgrapher, Emil Brodbeck, whose Amazon author page reveals that he was obviously an accomplished photographer.

According to Brodbeck’s 2003 obituary, he was born in Mt. Vernon, New York, and resided there until 1987. And according to this newspaper article, there was a Troop 3 in Mt. Vernon, NY, in 1955. So it seems very likely that this Scout was doing his part to serve the citizens of that New York community.

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