Phys 124: Particles and Waves
Section A01, MWF 10-10.50am CCIS 1-440
Prof. Dmitri Pogosian
Office: CCIS 2-105
Email: pogosyan@ualberta.ca
(not pogosjan)
Phys 124: Particles and Waves
Particles: this is about mechanics,
the laws of motion of massive bodies.
Large bodies (balls,cars,stars) follow
classical mechanics
Waves: motions of continuous
medium; air, water ..
Microscopic bodies (like electron):
behave as both particles and waves,
and are described by quantum
mechanics
1-1 Physics and the Laws of Nature
Physics: the study of the fundamental laws of nature
• Physicists strive to find the most simple, general laws
• these laws are expressed as mathematical equations
• much complexity can arise
from relatively simple laws
1-2 Units of Length, Mass, and Time
SI base units: length [L], mass [M], time [T]:
Length: the meter (m)
Was: one ten-millionth (1/10,000,000) of the distance from
the North Pole to the equator
Now: the distance travelled by light in a vacuum in
1/299,792,458 of a second
Time: the second (s)
Was: subdivision of a day (from Earth rotation)
Now: one second is the time for radiation from a cesium-133 atom
to complete 9,192,631,770 oscillation cycles.
Mass: the kilogram (kg)
Until 2019: One kilogram was the mass of a particular
platinum-iridium cylinder kept at the International Bureau of
Weights and Standards, Sèvres, France.
Now: derived from Length, time, and the measured with high
precision value of Planck Constant h (quantum physics)
1-2 Units of Length, Mass, and Time