This is lecture 2, about the atomic nature of matter and Brownian motion.

1. Enroll clickers

3. WebCT Demo

5. Brainstorming: What’s in this room? (If I don’t hear, shout again!) A Dark matter Quarks Electrons heat B Molecules Atoms Oxygen CO2, H20 Neutrons, protons, steam C People/students Desk, chairs, lights, chalkboard, air, neutraphils, bacteria, thoughts, pheremones, dust, C A’ Dark energy Space-time, heat, B’ Light waves, sounds waves (waves), gravity, motion, interactions C’ God, ideas, Jesus, thoughts, ___ual tension, physics

6. Brainstorming: What’s in this room? (If I don’t hear, shout again!) A quarks Electrons Photons(waves?) B Oxygen, CO2, carbon Atoms & molecules Protons neutrons C People, Electronics Materials (Furniture,shoes,sheets) Air, sensors A’ Heat, energy, Gravity, space-time B’ Light (radiowaves), sound, color, shadows, pressure, motion, C’ Electricity, smell Emotions Thoughts Mathematics Geometry Architecture physics Fundamental particles Complex materials “ Pure” materials Fundamental abstract things Complex abstract things Complex abstract things ?

7. Brainstorming: What’s in this room? (If I don’t hear, shout again!) A quarks Electrons Photons(waves?) B Oxygen, CO2, carbon Atoms & molecules Protons neutrons C People, Electronics Materials (Furniture,shoes,sheets) Air, sensors There are many physics concepts here, and there is no way we can cover them in order! A’ Heat, energy, Gravity, space-time B’ Light (radiowaves), sound, color, shadows, pressure, motion, C’ Electricity, smell Emotions Thoughts Mathematics Geometry Architecture physics Fundamental particles Complex materials “ Pure” materials Fundamental abstract things Complex abstract things “ Pure?” abstract things

8. Powers of 10 video This video explores our universe in powers of 10 for length scales (i.e. 1 meter, 10 meters, 100 meters, 1kilometer, etc.) It’s a bit old and hokey, but still pretty cool. It ends at the length scale we’ll talk more about today: very small (atoms) Feynman apple

10. Brownian motion as evidence for existence of atoms It took over 80 years in 1800-1900’s for scientists to become convinced about atoms

11. “ pollen grains” jiggle perpetually in room temperature water Fluorescent microspheres (1/1000 th of a millimeter) in water tethered to slide with single DNA molecules Viewed through a microscope… why are they jiggling???

12. Overhead Brownian Motion Demo In this demo, we are looking at the shadows of small spheres being shaken by a motorized corral Q: What will happen when we add a bigger ball bearing to the medium-sized ones? A: It will move more slowly than the medium-sized ones B: It will move the same as the medium-sized ones C: It will move more quickly than the medium-sized ones Discuss with your neighbors

13. Brownian motion in surprising places! (Laser demo) In this demo, we will be using laser light (described later in course) and seeing what it looks like when we shine on dry versus wet paint Dry paint: Keep your head very still, then move head slightly back and forth. Q: What is paint made of? Q: What do you think will happen with the wet paint?

17. Scanning Tunneling Microscopy http://www.ieap.uni-kiel.de/surface/ag-berndt/mikro/images/stm-320.jpg http://www.nrc-cnrc.gc.ca/multimedia/picture/images/html/nrc-nint_scan_tunn_mic-lr.jpg

18. STM can be used to build fun things one atom at a time http://www.almaden.ibm.com/vis/stm/corral.html Iron atoms on copper crystal Do you notice anything else in these images?

19. Structure of the atom Atom is composed of protons & neutrons in a dense “nucleus” Much less massive electrons “orbit” the nucleus in “shells” or “clouds” User:Yzmo on wikimedia commons