Transcript Document
SC300 Unit Two Alissa Rennie [email protected] AIM: alissarennie1 Unit 2 Reading: Chapters 14 and 15 Discussion: Measurement Seminar: Black Holes Project: Public Health Investigation SI base units • Meter (m) – length • Kilogram (kg) – mass • Second (s) – time • Ampere (A) – electric current • Kelvin (K) – thermodynamic temperature • Mole (mol) – amount of substance • Candela (cd) – luminous intensity Metric System • Decimal based system of measurement • Most common units: meter, sec, kg, liter, degree Celsius • Where is it used? Uncertainty (of measurement) To know one’s ignorance is the best part of knowledge. ~Lao Tzu, The Tao, no. 71 Evaluating uncertainty The Stars • Astronomy: study of objects in the heavens. • All stars send out energy, all are finite objects and therefore have finite stores of energy. • All stars have a beginning and an ending. How we study stars and their energy • 1. Their wavelength, which is measured by spectroscopy • 2. Their intensity, which is measured by a device like a light meter • 3. Their direction, which is measured by recording two angles—one up from the horizon (called the altitude), and the other around from north (called the azimuth) • 4. The variations of these wavelengths, intensities, and positions with time A star’s wavelength Why do stars have different wavelengths? • Field trip!! • http://cas.sdss.org/dr6/en/proj/basic/color/physlet/blackb ody.asp Star Varieties • Various colors • Brightness: distance and energy output - Luminosity – total energy emitted by a star How do you figure out how far away they are? Star Varieties • Various colors • Brightness: distance and energy output - Luminosity – total energy emitted by a star How do you figure out how far away they are? Triangulation! Birth of a Star • Nebulae collapse on themselves due to influence of gravity Death of a star • Size/mass dependent • If large enough the star could go supernova and form - Neutron Stars - Pulsars - Black holes A Black Hole: No Escape What is a Black Hole? What is a Black Hole? • A place where gravity is so extreme that it overwhelms all forces and not even light can escape. Black holes Black Holes What is the biggest obstacle to proving that black holes really do exist? Black holes Black Holes What kinds of evidence are there that they do? M82: Middle mass black hole M47: X-Ray Signal Presence Elusive intermediate mass black hole Black holes Black holes Black Holes Given what you know about scientific inquiry, why is the lack of direct evidence for black holes a problem for scientists? Black holes Field trip!!! • Lets make a black hole…. • http://hubblesite.org/explore_astronomy/black_holes/en cyc_mod3_q12.html Community health department investigation Community health department investigation Truman Middle School band director notes one-third of his students are absent on Wed, May 20th. Truman Middle School principal asks the health department if the school should be concerned about a health problem. Image credit: William Harris, http://science.howstuffworks .com/scientific-method6.htm Project Due by the End of Unit 2!! • First task: Where are absences taking place • Is there is a common reason for the absences? Explain. • Be sure to look at charts and Health Department info. • Luckily, your team has already collected all the school absences data and has put it on your Health Department intranet site which includes things such as the school event calendar, and interviews with the students’ parents, among others • Be sure to visit and analyze these links!! From the rubric… • · Student’s work demonstrates the ability to analyze the data such that they can develop and defend two viable hypotheses for the student absences based on the data and outside research. • · Student’s work develops six testable questions that relate to their investigation of the student absences. These questions clearly demonstrate that the student understands what would or would not be testable. These questions clearly relate to the investigation and hypotheses outlined by the student. • · Student’s work demonstrates an excellent knowledge of the scientific method and what constitutes a good hypothesis. • ·· Demonstrates a full and complete understanding of all questions. • · Formatting guidelines are met, citations follow APA style • · Unit 3 Discussion Unit 3 Discussion Reading – Chapter 6 • Waves and Electromagnetic Waves - Nature of waves - Properties - Electromagnetic spectrum Reading Chapter 8 • The Atom - Elements and their pieces - The Periodic Table Questions? Image credit: Microsoft Clip Art