Illinois Junior Academy of Science - Yearbook (Urbana, IL)

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The Effect of Temperature and Humidity J On Snowflake Variety WAYNE L. KOST THE EFFECT UF - HUMIDHY ff' Since the beginning of time man has been fascinated by the magic of snowflakes. It has been said that every snowflake that falls is different. Because of that fact, I became interested in snowflakes. To study them I used a method of preserving snowflakes developed by Dr. Vincent J. Schaefer. After observing the crystals, I found a great variety. It was my idea to see what factors determine the variety. It was my idea that temperature and humidity have a great effect on the formation of snowflakes. To test my idea I constricted a cold chamber, in which I was able to produce snowflakes. As these snowflakes grew and became heavy, they fell to the bottom of the chamber. I carried out a series of twelve experiments on the effect of tempera- ture and humidity on snowflakes. Each of the twelve experi- ments was conducted five times each to remove probability. From the results I can make the following hypothesis: Temperature and Humidity are definite factors in the germination and growth of snow crystals when they are in certain ratios.

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The Secrets Behind Color Television Picture Tubes M. GALVIN EEERET5 BEHIND r i. w Pn:'ruRr: rum: . El '- 53 The main parts of a color picture tube are the glass bottle envelope, which is composed of a faceplate, a funnel and a neck: the shadow mask, and a tri-element gun. ENVELOPE - The envelope is the glass bottle con- tainer of the working parts. FACEPLATE - The glass faceplate is the screen of the color television set. On it are placed phosphor dots that when excited by electrons, give off color, in this case green, blue and red. The reason these colors are used is that they are the primary colors of light. Phosphor is a photosensitive chemical which when excited by electrons will give off color. FUNNEL - The funnel is the middle of the glass bottle envelope. It is like an ice-cream cone in shape. NECK - The neck is the housing for the electron gun. The gun is inserted into the neck. SHADOW MASK -- The shadow mask has 400,000 holes etched into it. It is like the end of a gun barrel for the stream of electrons: it' guides the electrons to the certain dot whether green, blue or red. ELECTRON GUN - The electron gun is three guns within itself. One gun to excite the green dots, one to excite the blue, one to excite the red. Each gun is geometrically set to shoot and excite only its given dots. In this case if we turn on the green gun, it only lights up the green dots with the help of the shadow mask. Each gun scans the face- plate through 525 steps or lines 30 times a second. Mark 002 Printing Computer MARK enrmes gay Infant Jesus of Prague School Flossmoor Sponsor: Sister M. Rosaire, O.P. The Mark 002 is a digital computer capable of receiving decimal numerals from a card reader and a typewriter. Thesf: then convert the decimal numeral to binary, or base 2, nu- merals. This system can be used by the Mark 002 because of the twoness property of electronic switches - on and off. But, what does the Mark 002 do? By accepting two or more numeral, providing that you supply an add command after each, the Mark 002 can add those numbers using a serial adder circuit. The total num- ber of relays in all of the combined adders is 21 which are needed to add up to 2' or 31. In order to get the final binary sum printed out on the typewriter, the I key must be pushed. This activates a 40-step stepping relay which prints out the binary answer preceded by the expression would you believe. By pushing the reset button, all adders in the on position are returned to the off position, and the stepper will reset to the point of origin. Program panels with plug-in wires are used in order that anyone may pro- gram the Mark 002 in whichever way best suits his means. Being more than just a calculator, the Mark 002 can be considered a computer. It fulfills all of the qualifications of a computer, for it has input, control, computing, memory, and output units. And together with its special program- ming techniques, the Mark 002 can easily be adapted to many applications -- from binary adder to a control and output unit for many large-scale computers. 5 A M Radio oAvl-D M. BEAMS lay Thomas Jefferson Junior High School Springfield Sponsor: Mr. Donald Roderick The aim of my project was to start learning about radio and electronics in general. In a nine-month span, I built one transmitter, two diode radios, one transistor radio, and one grid-leak detector with two Class-A amplifiers. All of these were TRF receivers. The two diode receivers were counterparts of each other. One uses a IN34 diode as a detector. The other uses a IT4 pentode connected as a diode for a detector. The two-transistor transmitter uses one transistor as an oscillator. Feedback to sustain oscillation is provided by a disc capacitor. The output frequency is determined by a 220 mmfd. disc capacitor and L-1, a tapped transistor radio coil. The second transistor varies the voltage applied to the einitter of the oscillator and thereby modulates the r.f. signa. The r.f. output of this transmitter can be observed on an oscilloscope by connecting wires from the antenna and ground sides of L-1 to the vertical deflection plates of the oscilloscope. The transistor radio uses a 365 mmfd. variable capacitor and a tapped transistor coil for tuning, and one transistor as a detector. Two S.P.S.T. slide switches elect one or two-