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HOME EXPERIMENTS

SILENCE IN A VACUUM can be demonstrated with a glass flask and a small sleigh bell. Hang the bell on the end of a length of dowel or glass rod that can be pushed through the hole of a snug-fitting flask stopper; then put a little water in the flask, boil it long enough for steam to drive out the air, remove it from the heat, and fit the stopper in as soon as the steam stops expanding. Cool the flask with running water and shake it near your ear. You will barely hear the bell tinkle, the steam having produced a partial vacuum—sound waves will not travel through a vacuum. But let air in and again shake the flask, and the tinkle will be heard clearly.
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This looks like it would be a blast. Although it does seem like you might eventually cut a large circle in the ice.

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A MERRY-GO-ROUND FOR THE ICE

BY L.B. ROBBINS

EXHILARATING sport is furnished open-air enthusiasts by the novel ice merry-go-round described in this article. The device, although it reminds one of an ice boat, is, however, a new departure in ice coasting, the novelty consisting in the fact that the merry-go-round, which is itself stationary, swings the riders, who are carried on sleds, in circles around it. When desired, the cord or rope that holds the sled to one of the revolving arms, is released, and the sled with its rider is sent flying off over the ice. With a good breeze blowing, the merry-go-round revolves with considerable speed, yet is perfectly safe, if constructed according to the instructions. It can be built by anyone who has some knowledge of tools and how to use them, and who possesses enough ingenuity for details of construction.
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CHEMISTRY: An Exciting and Profitable Hobby

How to Set Up Your Laboratory

By RAYMOND B. WAILES

WITH simple equipment requiring surprisingly little financial outlay, you can build in your home a small chemical laboratory that will provide a fascinating hobby. Here you may amaze your friends with seemingly magical chemical tricks, as by the manufacture of paint that shines in the dark or of writing inks that disappear unless the secret of bringing them back is known. You can manufacture useful things for the home, as soap or liquid court plaster. You can test gold rings and ivory piano keys to see whether they are genuine. If you wish, you can investigate the chemical processes used in industry, with the ever-present possibility of an important discovery. To the real dyed-in-the-wool experimenter, chemicals in themselves are intriguing, and a beautifully colored precipitate or a startling formation of crystals is its own reward for the trouble of preparation.
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CRAFTSMEN ON WHEELS

Scooter Has Three Speeds. Before becoming a cadet-midshipman at the US Merchant Marine Academy, William R. Kern welded some 3/4″ pipe, added a few gears, chains, and a 1/2-hp. motor, and came up with the two wheeler shown above. It carries him 80 miles on a gallon of gas at an average speed of 30 m.p.h. A V-belt, the tension of which may be varied by an idler pulley acts as a clutch to engage the three-speed transmission. The latter transmits power to the rear wheel through a chain. Gears were cut on a milling machine and hardened.
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SPORTS RADIO is Combination Cane and Seat

By FRANK TOBIN

CONSISTING of a compact yet powerful battery receiver mounted on a conventional cane-seat which can be purchased for a dollar or two, the radio illustrated forms a handy set for hikers, sports spectators, and campers. The circuit, designed around three of the new American-made midget tubes, consists of a pentode regenerative detector, resistance coupled to a pentode amplifier which in turn is resistance coupled to a second audio-amplifier stage. Regeneration is controlled by a 25,000-ohm potentiometer. Since the commercial type of antenna coil shown in the diagram has no tickler winding it will be necessary to provide one by winding approximately thirty-five turns of No. 38 double-silk-covered wire around the lower end of the long, flat grid coil.
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From Block to Blockhead in Two Days’ Time

There’s no such thing as mass production in the dummy-making business. One day your friend Charlie McCarthy was a chunk of wood. Next afternoon he was Charlie McCarthy, ready to talk if someone would think out loud for hint. In two days a block becomes a blockhead, without benefit of factory methods. Every dummy is made to order, chiseled to fit the personality desired by the ventriloquist; only one machine operation takes place, the slitting of the dummy’s chattering chin by a handsaw. The rest is hand work. Above, you see a dummy’s brain: the finger controls which manipulate chin and eyeballs. From top down around the page are the first stages in a dummy’s life a cube of basswood or buckeye; chiseling out the face contours; shaping the mouth; screwing the head together after installing “brains,” and sawing the chin.
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Upturned Rowboat Forms Roof of Tiny One-Room Cottage
All’s shipshape in this little cottage at Whitstable in Kent, England! An upturned rowboat forms the tight gable roof of the one-room house, whose walls meet in a point beneath the bow of the boat. Not so nautical is the big brick chimney.

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Fight Artillery Duels in Fascinating War Games

by PAUL R. RANNIE

You fight real, deadly battles on a small scale in these fascinating war games, which have all the strategic elements of nation-against-nation campaign. Exploding battleships, forts and tanks and an accurate long – range mortar compose your fighting forces, built as described in this article.

MANY of us have been fascinated by photographs or moving pictures of huge artillery pieces sending their shells screaming up into the air on their way toward a target perhaps out of sight beyond the horizon. The gunners usually do not see the target, but fire in a certain direction and at a certain elevation from data furnished to them.

The toy mortar shown in the photographs and drawings will shoot small soft clay balls in the same manner as the big guns and with surprising accuracy. It can be used as the basis of some interesting games that will attract many of the older folks in addition to the youngsters. Easily constructed targets which explode (mechanically speaking) when hit, a moving target and others are also part of the equipment described.
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Is this to show your daughter what she’ll look like when she gets knocked up? Seems like a mean thing to do to a little kid.

Personalized Laundry Bag for Child’s Room
Topped with a portrait of its little owner, this child’s laundry bag looks much like a life-size doll, and its novelty will go far to encourage children to take care of their soiled clothing. A good close-up snapshot of the child is selected and that portion of the negative showing only the head and possibly part of the shoulders is enlarged as close to 8 x 10 in. as possible. Read the rest of this entry »

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Comic-Strip “Talkies”

GIVE CHILDREN ENDLESS FUN AT HOME

By Morton Bartlett

UNIQUE comic-strip “talkies” can be given in your own home at trifling cost. The pictures are thrown upon a screen by means of a simply made magic lantern, and the children speak the lines of the various characters through a home microphone connected to an ordinary radio receiving set.

The materials are listed on page 85. The first step is to make the lantern. Its width is equal to the focal length of the magnifying glass which will be the lens. Determine this by tacking a piece of paper against the wall 10 ft. from a lighted lamp. Hold a ruler perpendicular to the paper, and run the lens, perpendicular to the ruler, along the inch marks. At some point a clear image of the lamp will be seen on the paper. The focal length may now be read from the ruler. This distance is the dimension YM in the drawings. Having found this basic dimension, cut ten pieces of wood as specified in the list.
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Puppets Made from Light Bulbs
ELECTRIC-LIGHT bulbs and radio tubes form the basic materials with which Alfred Wronkow, of New York City, fashions the amusing caricature figures shown above. For the “social-light” wedding scene pictured, Wronkow used common household items to dress the principals and attendants at the fusing of “Claire Coppertop,” a dainty twenty-five-watt bride, and “John Glasstum-my,” her husky seventy-five-watt groom.

A One-Man Show with a Magic Hat

IMPERSONATING different characters by appearing in a succession of hats is a trick well-known to the stage comedian and one that you can easily perform in your home with the aid of the simple ring of felt shown here. By folding and twisting it, the wearer transforms himself successively into a general, a president, a clown, and as many other personages as ingenuity may suggest. Make the ring of heavy hat felt if procurable; otherwise, have two thicknesses of the lighter grade, that every dry-goods store sells, stitched together on a sewing machine. A mirror behind a screen will help you to adjust your hat carefully but speedily for each impersonation. To aid in learning the shapes, the indicated letters may be chalked on the ring. At the end of entertainment, pull the ring down around your neck and say, “Myself.”