# 2005 - PJAS Astronomy Award Winners

Timing a Day by Night
Corinne Bishop (Macungie Middle School)

Project Description:

The purpose of the experiment was to discover if using time-exposure photography could accurately measure the length of a day. The hypothesis for this project is that if measurements of stars are taken correctly, then the star trails from 20-minute time exposures will support the accepted 24 hours timing of a day, because apparent star movement is 15 degrees per hour. Time-exposure photography occurs when the shutter of a camera is left open for an extended amount of time. In this experiment, a twenty-minute time exposure was employed to take pictures of stars.  Then, a protractor was used to measure the angle formed by the edges of the photographed star trails with Polaris as the central point.  All the angles measured were measured as 4.95 degrees. Then, these measurements were used in the following equation: 24 hours x 60 min / 20 min = 72 (degrees). If the result equaled 360, then the 24 hour day was correct.  More than 360 degrees would support a day length measured in solar day degrees; less would support a sidereal day.  From the data collected, my hypothesis of the 24-hour day was not supported, and the sidereal day seemed more correct.

Impact Craters
Thomas Pazamickas (St. Monica School)

Project Description:

Impact craters can be divided into 2 groups based on their structure, simple or complex. The ejected material can be in 2 forms, ejecta blankets or ejecta rays, depending on the speed at which the material was ejected. My question: How does the size of an object of the same weight affect crater formation when impacting a sandy surface?

HYPOTHESIS: The sphere with the smallest surface area, dropped from the greatest height will make the deepest crater due to the greater force per unit area generated upon impact. A higher velocity and kinetic energy from the highest free fall will also be a contributing factor. The method used to test my hypothesis was to use varying circumferences of the same weight, same material sphere. These spheres were dropped from a variety of heights. The resulting crater was measured, surrounding structures identified, and the velocity and kinetic energy calculated.

RESULTS: The factors affecting impact crater formation are the surface area of the impactor, velocity, and kinetic energy. As the surface area of the impactor decreases and the velocity at which it travels increases, the kinetic energy increases. The limited surface area of the impactor increases the force per unit area at impact making the crater deeper with larger ejecta. The slight subsoil compression that occurred upon impact was visible. The ejecta was a blanket and consisted mainly of the upper sides of the crater walls. There was evidence of ejecta rays at the higher free falls. The deeper craters had steeper walls while the shallow craters had less of a slope.

CONCLUSION: The factors affecting the formation of impact craters are the size of the impactor, its velocity, and its associated kinetic energy.

A Spectral Analysis on Orion's Nebula
Britni Kress (Trinity High School)

Project Description:

My project is "A Spectral Analysis on Orion's Nebula." I used a radio telescope in Green Bank, WV to determine what kind of electromagnetic radiation Orion's Nebula gave off. I converted analogue data taken from the telescope to a standardized set of data. I then found other points that showed Orion's Nebula's electromagnetic radiation and graphed them. I compared the graph to other graphs of thermal and nonthermal radiation. I determined from these graphs and scientific research that Orion's Nebula gave off free-free emission.

Crater Formation and Energy Transfer
David Riddell (J.R. Masterman Laboratory and Demonstration School)

Project Description:

In this experiment I investigated the effect of a given meteor trajectory on the resulting impact crater. I also investigated whether frozen projectiles would give a more authentic simulation of a meteor impact event. Then, I calculated the energy changes that result from meteor impacts. I predicted that different angles of impact would create craters of different sizes, shapes, and with different debris distribution. I also believed that the majority of the energy from the impact would be transferred from kinetic energy into heat and sound. To simulate the meteor impact I used frozen and room temperature potato cores and a potato gun aimed at a sand pit. The potatoes were launched at the sand pit at four different angles. The potatoes were all launched from the same distance. This distance was calculated using triangulation. Then I constructed a pendulum and a box to determine energy transformation. I also determined the velocity of my projectiles using the drop of elevation of the projectile due to the force of gravity. I found that crater shape was similar for both the frozen and room-temperature projectiles. The frozen projectiles remained more intact than their room-temperature counterparts. The frozen potatoes also deflected off the sand at low-angle launches. Experiments like this one could be very important to the study of the Earth's prehistory. It provides information concerning the consequences of meteor impacts. I plan to continue examining impact events, and I would like to measure the impact ejecta more in depth.