Table of Contents:
(1.) Introduction and Background Notes
(2.) Testing Factors that Affect Impact Crater Size
(3.) Experimenting with Impact Craters
(4.) Experiment 1: General Comments
(5.) Experiment 1: Tables and Graphs
(6.) Data Analysis, Evaluating Design, Analyzing Assumptions
(7.) Experiment 2: Procedures
Introduction and Background Notes
Central to good science are accurate observations, testable hypotheses, well-designed experiments or other tests, and reasonable data analyses. The purpose of Laboratory 1 is to introduce you to the basics of designing and analyzing experiments. The following two laboratory exercises will provide you with further steps in organizing and analyzing data.
Many interesting experiments are impossible to do in a normal undergraduate science laboratory setting. For this reason, your introduction to designing an experiment that has relevance in “the real world” involves a computer simulation. This program will allow you to create a virtual impact crater on Earth.
Have you seen any disaster movies lately? You know the kind, where some great catastrophe is about to befall all of humanity and threaten the very existence of life on Earth? Movies such as “Armageddon” and “Deep Impact” depict Hollywood‟s take on the effects of an asteroid or comet that is on a collision course with Earth. How realistic are these films? What would the effects of such an impact really be? Are they relevant to real life?
Meteorite impacts have been getting plenty of attention in recent years. They are regarded by the public as the annihilator of dinosaurs and as the potential destroyer of civilization. Scientists understand that impacts are an integral part of the processes that formed the solar system, and which continue to modify planets more than four billion years later. Additionally, meteorite impact events have influenced the biological history and diversity of life on Earth; understanding them may be particularly relevant to our own survival.
Researchers monitor the skies, counting and tracking asteroids and comets that are likely to cross Earth‟s path, as it makes its yearly trip around the Sun. Why? There are many other objects orbiting the Sun, besides our home planet: seven other planets, tens of moons, and thousands of asteroids, to name a few. There are still other objects orbiting the Sun; some of these are called Earth-crossing asteroids, because they have elliptical orbits that cross the orbit of Earth and the other inner planets. These asteroids may come very close to Earth, and
Experimental Analysis 1
occasionally there is a collision. Therefore, there is some rationale to studying them, beyond mere scientific curiosity. Researchers hope to identify any potential collision, before it actually happens. Remember the premise to those science fiction films?
A meteorite is a general term for any extraterrestrial object, regardless of its size or composition, which is large enough to strike Earth‟s surface and to make a crater. An impact crater is formed when a meteorite (asteroid or comet) crashes into a larger planetary body that has a solid surface, such as the Earth. Impact craters cover the surface of the moon, and have been identified on all of the rocky bodies of the solar system. Currently, about 160 impact craters have been identified on Earth‟s surface. You can see a map of their locations here: http://www.lpi.usra.edu/publications/slidesets/craters/slide_2.html One of the best known impact craters is Barringer Crater in Arizona. It is nearly 1.2 kilometers across and some 170 meters deep. The crater was formed approximately 49,000 years ago by the impact of a nickel/iron meteorite 50 meters in diameter, traveling at a velocity of 11 kilometers per second. You can check it out for yourself. Visit http://www.meteorcrater.com/ for a short animation and more information.
Massive impacts are devastating events. The