9/27/2023 0 Comments Earthtime website![]() ![]() In the final part, students engage in a summary exercise where they apply what they have learned to test the two competing hypotheses. After this, the chemistry and physics behind geochemical laboratory techniques, ion exchange chromatography and isotope ratio measurements using a mass spectrometer, are explained using models, movies, posters, and analogies to familiar physics. An introduction to statistical inference from small samples can also be added to this exercise. The (pre-counted) unknown quantity of beads represents the isotopic composition of zircon from four samples-the Deccan Trap basalts, the Chicxulub impact melt, and ash layers above and below the K-T boundary -and the students' measurements are used in the final part of the module. Here the students determine the number of beads in a large bucket without counting them all by adding a precisely known number of "tracer" beads and averaging ratios from several small samples of the mixture. Next, the technique's accuracy despite loss of parent and daughter atoms during analysis, as well as the use of isotopic ratios rather than absolute abundances, is explained with an activity on isotope dilution. ![]() Manipulating groups of double-sided chips labeled with U and Pb isotopes reinforces the concept that an age determination depends on the Pb/U ratio, not the absolute number of atoms present. In this module, the students start by exploring the concepts of half-life and exponential decay and graphically solving the isotopic decay equation. The curriculum teaches the science behind uranium-lead dating using tables, graphs, and a geochronology kit. In the second part, we use a curriculum developed for and available on the EARTHTIME website (). Students also discuss geologic features relevant to the K-T boundary problem and get the chance to examine basalts, impact melts and meteorites. We cover all the steps from sampling an outcrop to determining a final age. Students use different techniques, such as magnetic separation, density separation using non-toxic heavy liquids, and mineral identification with a microscope. Activities are divided into three parts: In the first part, the instructors lead hands-on activities demonstrating how rock samples are processed to isolate minerals by their physical properties. The theme of our 2.5-hour module is the timing of the K-T boundary and a discussion of how geochronology can be used to evaluate the two main hypotheses for the cause of the concurrent extinction-the Chicxlub impact and the massive eruption of the Deccan Traps. The workshop focuses on uranium-lead (U-Pb) dating of zircons and its application to solving a geological problem. The number in the title refers to a measurement of time, as the earth’s day was shortened by 1.26 microseconds.The authors taught an educational module developed as part of the EARTHTIME (outreach initiative to 215 high school students from a Massachusetts (USA) High School as part of an "out-of-school" field trip. Inside Echelman’s studio, the physical form of Earthtime 1.26 was digitally modelled with inspiration from a scientific data set describing a single geological occurrence in one part of the world (a 2010 earthquake in Chile) that caused ripple effects around the globe, which sped up the earth’s daily rotation. These include architects, designers, and model-makers in the studio, as well as an external team of aeronautical and structural engineers, computer scientists, lighting designers, landscape architects, and a fabrication team. To create the sculptural form, Echelman works with teams both inside and outside her studio. Each time a single knot moves in the wind, the location of every other knot in the sculpture’s surface is changed in an ever unfolding dance of human-made creation with the forces of nature beyond our control. These sculptures serve as symbols of interconnectedness – composed of countless intertwined fibers. The Earthtime sculpture series seeks to heighten our awareness about the way we are all interconnected with one another and our planet. ![]() ![]() I invite viewers to pause beneath my sculpture for a moment to contemplate our interconnectedness with each other and our planet, and to become aware of our own sensory experience.” – Janet Echelmanīetween August 11th and October 3rd, 2021, Janet Echeman’s Earthtime 1.26 sculpture will be exhibited at Munich’s Odeonsplatz, presented by Mercedes-Benz. My artwork reflects an interconnectedness of opposites – flexibility with strength, earth with sky, things we can control with the forces beyond us. “I’m excited to install Earthtime 1.26 Munich in the historic Odeonsplatz, where past and present intertwine to create a dynamic urban now. ![]()
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