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

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PHYSICS

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Magnetic Elements TOM AHLQUIST ll ll Jesltsonville High School Jacksonville, Illinois Sponsor: Mr. Richard Ommen The objective of this project was to detect, measure and analyze the relative changes of declination, inclination and horizontal intensity of the earth's magnetic field at a fixed station for a period of 30 days. It was first necessary to gather information on the con- struction and operation of various kinds of instruments used in making magnetic observations. From this information it was decided to construct on induction coil for measuring inclination and an oscillating type variometer for measuring declination and horizontal intensity. In addition to the basic magnetic measuring instruments it was necessary to build devices for testing the magnetic property of material going into the construction of the instruments and for measuring time in hundredths of a second. ' After acquainting myself with the theories of the origin and variations of the earth's magnetic field the next step was to orient the measuring instruments for observations. The observation site chosen was as free from local anomolies as possible and still be reasonably convenient for taking readings. The magnetic meridian established with a large compass and a taught line was used to line up the axis of rotation of the induction coil. A vibration free bench anchored to the concrete floor at the magnetic station was used to mount the oscillating variometer while the induction coil base was permanently mounted directly to the concrete floor. From this project I concluded that the angle of inclina- tion and declination as well as the horizontal intensity do exhibit a daily variation. The data gathered and recorded indicated variations of each element measured. These varia- tions seemed to be in phase and to follow a 12 to 14 day cycle of peak minimums and maximums. JACK DAVID ADAMSKI gap Cicero School Cicero, Illinois This project was an experimental investigation of the heave stability of the Peripheral Jet ground effect machine. This is a relatively new concept in hovering flight of a gas engine powered, single plenum chamber. The lift, rise, height and power relationship were determined by using va- rious engines and propeller pitches. Also by bleeding air into and out of the'air cushion, to evaluate the change in lift. The Gem was allowed to hover at a given height and pro- pelled forward with a top mounted engine. Much of the information for this project was supplied by the United States Army Aviation Material Laboratories, by library re- search, and by personal experimentation. Because of limited exposure to involved mathematical and engineering formu- las, at age 14, I have yet much to learn from this project. Since this vehicle can navigate over most types of ter- rain, its future values are yet to be ascertained as regards transportation vehicles. Monomolecular Films SHARYN ELLMAN ll ll Highland Park High School Highland Park, lllinois Sponsor: Mr. H. E. Hanson A monomolecular film is a film at an interface between two states of matter. An original study was made of the properties of these films at different temperatures to de- termine their collapse pressure, the area per molecule at that pressure, and whether phase transitions occur. Monomolecular films of stearic and oleic acid were spread on the surface of water in a glass tray of a hydro- philic film balance, which I constructed. Extreme care was taken to keep the films free from contamination. The experiments show that although the molecular struc- ture of oleic acid and stearic acid are similar, the double bond between two of the carbon atoms of oleic acid weakens the cohesive forces of the hydrocarbon group, giving it a lower collapse pressure. Reduction of temperature lowered the collapse pressure. Phase transitions similar to the change-of-state of three dimensional systems, occurred at several temperatures. When below their melting points, their state was not that of a solid. They behaved more like a two- dimensional gas. An equimolar mixture of stearic and oleic acid obeyed Dalton's Law of Partial Pressures, the collapse pressure approximately equaling the sum of the individual collapse pressures of stearic and oleic acid.