ERS103H5 Midterm: Midterm Definitions Answers
Document Summary
Atoms of the same chemical element that have the same number of protons (i. e. atomic number) but differing number of neutrons (and weight): radioactive isotopes. Radioactive decay of parent to daughter isotope occurs at known rate (decay constant) and forms a clock to measure age. Each isotope decays at its own stable decay rate: half-life. The time for half of a parent to decay into daughter: refracted waves. Waves that are bent at boundaries: reflected waves. Waves that are returned at boundaries: p-waves (primary waves) Compressional waves, fast, travel through all materials: s-waves (secondary waves) Shear waves, travel only through solids: abrupt velocity changes. Used to define changes in rock composition and define sections of the earth. Hard, rigid portion of the earth, composed of the crust and upper mantle, it is brittle and results in earthquakes, they are the plates in plate tectonics: asthenosphere. Below the lithosphere, low-velocity zone: liquid outer core.
