1 / 13

30,000K

Iron melts. Surface of Sun. 2000K. 0. 30,000K. Death Valley. Nitrogen liquefies. Antarctica. Room. 200K. 0. 75K. 300K. 325K. Helium liquefies. Outer Space. 0. 1K. 3K. 4K. MicroKelvin = 10 -6 K , a million times colder than outer space!

niabi
Télécharger la présentation

30,000K

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Iron melts Surface of Sun 2000K 0 30,000K Death Valley Nitrogen liquefies Antarctica Room 200K 0 75K 300K 325K Helium liquefies Outer Space 0 1K 3K 4K MicroKelvin = 10-6 K, a million times colder than outer space! “Liquid Helium : Laser-cooled Atoms” = “10,000 Suns : Room”!!

  2. Scientific Attitude: What’s that? • Understand Contexts in which scientists present information to you Reality is complicated (e.g., crystal of salt). Visualize with a simple model (e.g., ball- stick model). Use model but understand its limitations. EXAMPLE: Particle Model (The object collapses into a mathematical point, also known as the center of mass) Nice simplification, but model has limitations! DEMO: Happy Ball, Sad Ball • Critically think through information - don’t be a Blind Believer! - Galileo: “All objects fall at the SAME rate”. Do they??? DEMO – Steel, wood, styrofoam balls - Does the Loch Ness monster exist? If so how BIG do you think it is? - Do you believe in MAN-MADE global warming? • Engage with other learners, understand other points of view Class room discussion, Work on Homeworks in groups, Talk with professor in Office Hours • Reflecting and Acting on scientific information you have processed Would you spend tax payer money on Nessie? On policy to reduce global warming?

  3. Reading Question 1.1 What is a “particle?” • Any part of an atom. • An object that can be represented as a mass at a single point in space. • A part of a whole. • An object that can be represented as a single point in time. • An object that has no top or bottom, no front or back. Slide 1-6

  4. Reading Question 1.1 What is a “particle?” • Any part of an atom. • An object that can be represented as a mass at a single point in space. • A part of a whole. • An object that can be represented as a single point in time. • An object that has no top or bottom, no front or back. Slide 1-7

  5. Units • Science is based on experimental measurements, and measurements require units. • The system of units in science is called le SystèmeInternationale d’unitésor SI units. • The SI unit of time is the second, abbreviated s. • 1 s is defined as the time required for 9,192,631,770 oscillations of the radio wave absorbed by a cesium-133 atom. • The SI unit of length is the meter, abbreviated m. • 1 m is defined as the distance traveled by light in a vacuum during 1/299,292,458 of a second. An atomic clock at the National Institute of Standards and Technology is the primary standard of time. Slide 1-78

  6. Units • The SI unit of mass is the kilogram, abbreviated kg. • 1 kg is defined as the mass of the international standard kilogram, a polished platinum-iridium cylinder stored in Paris. • Many lengths, times, and masses are either much less or much greater than the standards of 1 m, 1 s, and 1 kg. • We use prefixes to denote various powers of 10, which make it easier to talk about quantities. Slide 1-79

  7. Typical Lengths, Masses, and Times = Thickness of a human hair Please make a note of the boxed items

  8. Precise Measurement: Time Q: Why bother? A: Consider GPS! Advance in Fundamental Concept: Convert distance measurement to time measurement Advance in Technology: The most precise clock ever! Another example: Advance in fundamental concept: Stop atom dead in its tracks, examine at will! Laser Cooling & Atom Trapping [Nobel Prize in Physics 1997, 2001, 2005, 2012] Advance in technology: Atom Laser, Nanolithography, Quantum Computer, Quantum Teleportation (?)

  9. SAMPLE QUIZ (15pts) • Recall the discussion in class on GPS. In one line explain why we typically need at least three satellites. In another line explain exactly what is the fundamental reason behind the need for super-accurate clocks to enable "high resolution GPS". (5pts) WHY 3 SATELLITES? _____________________________________________________________________ WHY ACCURATE CLOCKS? _____________________________________________________________________ 2) Choose the answer that best estimates the length of your arm in meters: (2pts) • 10m b) 3m c) 2m d) 1m e) 0.1m 3) Estimate the temperatures for the following in Kelvin: (8pts) a) The surface of the sun: b) Nitrogen liquefies at: c) Antarctica: d) Typical room temperature at Miami U: e) Death Valley, CA: f) Outer space: g) Helium liquefies at: i) Coldest matter in Universe known to us:

More Related