waves…. chapter 8nsl/lectures/phys10062/chapter 8... · 2013-02-19 ·...

Waves…. Chapter 8

Examination #1 Range was 0-109 pts…………Maximum pts =119 with the extra credit problem Average grade of Examination #1 =89.7 or 90 pts out of 109 Average of 82.6% Number of students that scored above 100 pts on exam…21 Highest grades…..>108 Julia Zanotelli Kevin Salat Jennifer Poth Christian Metzier Bridget Mooney Nicolas Montoya Jameson Crawford Genevieve Bellon

Meteors  typically  cause  sonic  booms  when  they  enter  the  Earth’s  atmosphere,  and  the  one  that  occurred  over  Chelyabinsk  was  forceful  enough  to  sha=er  dishes  and  televisions  in  people’s  homes.  Car  alarms  were  triggered  for  miles  around,  and  the  roof  of  a  zinc  factory  par@ally  

collapsed.  Video  clips,  uploaded  by  the  hundreds  star@ng  early  Friday  morning,  showed  ordinary  mornings  

interrupted  by  a  blinding  flash  and  the  sound  of  sha=ering  glass.  

•  As  residents  of  Chelyabinsk  began  their  day  on  Friday,  a  10-­‐ton  meteor  around  10  feet  in  diameter  was  hurtling  toward  the  Earth  at  a  speed  of  about  10  to  12  miles  per  second,  experts  from  the  Russian  Academy  of  Sciences  reported  in  a  statement  released  Friday.  Scien@sts  believe  the  meteor  exploded  upon  hiLng  the  lower  atmosphere  and  disintegrated  at  an  al@tude  of  about  20  to  30  miles  above  the  Earth’s  surface  —  not  an  especially  unusual  event,  the  statement  said.  

NY  Times…Friday  February  15,  2013  

Asteroid:  A  rela@vely  small,  inac@ve  body,  composed  of  rock,  carbon  or  metal,  which  is  orbi@ng  the  Sun.        Comet:  A  rela@vely  small,  some@mes  ac@ve  object,  which  is  composed  of  dirt  and  ices.  Comets  are  characterized  by  dust  and  gas  tails  when  in  proximity  to  the  Sun.  Far  from  the  Sun  it  is  difficult  to  dis@nguish  an  asteroid  from  a  comet.        Meteoroid:  A  small  par@cle  from  an  asteroid  or  comet  orbi@ng  the  Sun.        Meteor:  A  meteoroid  that  is  observed  as  it  burns  up  in  the  Earth's  atmosphere  -­‐  a  shoo@ng  star.        Meteorite:  A  meteoroid  that  survives  its  passage    through  the  Earth's  atmosphere  and  impacts  the    Earth's  surface.        

h=p://www.universetoday.com/99950/watch-­‐live-­‐as-­‐asteroid-­‐2012-­‐da14-­‐whizzes-­‐past-­‐earth/  

Washington  Post  

Energy Transfer by Waves

•  Wave – A traveling disturbance

•  Properties of waves – Wavelength – Frequency – Velocity – Amplitude

The Doppler Effect h=p://www.youtube.com/watch?v=ZRGg7e9b5wY&NR=1&feature=fvwp  

h=p://www.youtube.com/watch?v=-­‐d9A2oq1N38   Sonic Boom

h=p://youtu.be/4cCk1MXJHm0    Evidence  that  everything  is  moving  away  from  us  

An  echocardiogram  uses  sound  waves  to  produce  images  of  your  heart.  This  commonly  used  test  allows  your  doctor  to  see  how  your  heart  is  bea@ng  and  pumping  blood.  Your  doctor  can  use  the  images  from  an  echocardiogram  to  iden@fy  various  abnormali@es  in  the  heart  muscle  and  valves.  

The Electromagnetic Spectrum

h=p://www.youtube.com/watch?v=58fs5yI8K9I  

The Electromagnetic Spectrum

Heat  Escaping  from  People  

Visible  Light  

•  Visible light – Range: 700nm–400nm

•  Colors – Slices of electromagnetic spectrum

A  Glass  Prism  Separa@ng    White  Light  

Path  of  Light  through    the  Human  Eye  

Chapter 8

Great Idea: All of the matter around us is made of atoms, the

chemical building blocks of our world

The Atom

Chapter Outline •  The Smallest Pieces •  The Structure of the Atom •  When Matter Meets Light •  The Periodic Table of the Elements

Dividing a Bar of Gold

Elements

•  John Dalton – Father of modern atomic theory – Cannot break down elements – Elements composed of atoms

•  Example: Water molecule is 1 oxygen atom and 2 hydrogen atoms

• Helium, carbon, aluminum, copper, gold

Everyday  Elements  

The Structure of the Atom

The Nuclear Regulatory Commission

•  Logo: highly stylized atomic model

Bohr  Atom  

Electron  Energy  Levels  

Atomic  Model  

Photons: Particles of Light •  Photon absorbed – Used to move electron to a higher

energy state

•  Photon emitted as electron moves to lower energy state

Photons:  Par@cles  of  Light  

Photons  -­‐  cont.  

•  Quantum leap or jump -electron disappears from original location and reappears in final location-never at positions in between

Spectroscopy •  Atoms emit and absorb different

photons •  Depends on differences between energy

levels •  Each atom has distinct set of photons •  Spectrum: all photons emitted by an

atom – Used for identification

Na, K, and Li – Give Distinctive Colors to a Flame

Spectroscopy – cont. •  Glass

prism

Spectroscopy  –  cont.  

•  Line spectra for H, Na, and Ne

h=p://www.youtube.com/watch?v=l4yg4HTm3uk  

The Periodic Table of the Elements

The  Science  of  Life  

•  Spectra of life’s chemical reactions – Used to determine how enzymes work – Used to identify pollutants emitted from

automobile exhaust pipes

Technology  

•  Lasers – Produce a beam of light

The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation. The emitted laser light is notable for its high degree of spatial and temporal coherence.

Ac@on  of  a  Laser  

Lasers  Have  Many  Uses  

Periodic Table of the Elements

•  Systematizes elements •  Columns contain similar elements – Alkali metals: soft, silvery metals – Noble gases: colorless, odorless, and inert

Periodic Table of the Elements

Why the Periodic Table Works: Electron Shells

•  Patterns mirror arrangement of electrons in shells

•  Pauli exclusion principle •  First shell 2 electrons, second shell 8,

etc.