Physics 20

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Physics 20

• Introduction to Physics

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What is Physics?

• a branch of Science
• What are some other branches we know?
• Chemistry, Geology, Biology, Astronomy,
  Environmental Science, Social Sciences..

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What is Physics?

• Physics comes from the Greek word Physis which
  means nature
• So is Physics the Science of Nature?
• Wait a sec! What is Biology?
• Bios-life
• logos- the study of.
• So biology is the Science of Life.
• If we use the word nature to refer to the whole
  external universe, then we are getting close.

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What is Physics?

• It is the science of matter, its motion, as well
  as space and time.
• Physics can be thought of as humanitys attempts
  to describe and explain our universe.

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What is Physics?

• Physics has many different branches within it
• http//hyperphysics.phy-astr.gsu.edu/hbase/hph.htm
  l
• Some of the topics commonly
• covered in Physics 20
• Waves, Light, and Heat
• Physics 30 Kinematics and Dynamics, Electricity,
  Mechanical Energy, Nuclear Physics

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What is Physics?

• Is this all of Physics?
• Not by a long shot! But all of the topics that
  we discuss here are relevant and used everyday by
  researchers!

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What is Physics?

• One interesting way to look at Physics is the
  scale which it encompasses.
• Physicists are concerned with the most elementary
  of particles that make up matter in the quantum
  realm the pieces that make up atoms!
• They are also concerned with the stars and other
  heavenly bodies that are amazingly large and far,
  far away.

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What is Physics?

• Here we have a number of galaxies, each contains
  somewhere between ten million and one trillion
  stars.
• The universe itself is estimated to have 9 1021
  stars (9 billion trillion stars)

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What is Physics?

• When we really start to look for Physics, we can
  find that it is everywhere!
• Medicine, Cell-phones, cars, TVs, sports,
  thats right sports! (think of the sweet spot
  on a bat, thats Physics)

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Is Physics only for Physicists?

• A Physics education is a key to understanding
  science, and can only help to open doors for the
  future.
• The lines between Physics and other science areas
  like Biology become blurred in many areas of
  study. For example Medical Physicists and
  Ultrasound Technichians have a great amount of
  knowledge of both Biology and Physics (they also
  make lots of money).
• The point is, many of the disciplines of science
  (if not all) are interrelated.

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The Nature of Science

• Physics relies upon empiricism.
• Empiricism the practice of relying on
  observation and experiment especially in the
  natural sciences.
• In Science, we make observations, and from these
  observations questions are often raised.
• These questions can lead to experimentation with
  more observations, which can then lead to more
  questions. Its an ongoing cycle!!

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Where Did Physics Start?(by no means is this
complete)

• Since Astronomy is a sub-field of Physics, we can
  say that our earliest records of Physics come
  from Babylonia (modern day Iraq) around 2000 B.C.
  Here astronomers looked up and recorded what
  they saw on stone tablets.
• Later came the Greeks.
• 384 B.C. Aristotle tried to write laws which
  governed the motion of objects. Although they
  were wrong, they were an attempt. He also
  believed in a geocentric universe.

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Where Did Physics Start?
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Where Did Physics Start?

• Nicolaus Copernicus receives his copy of his book
  De Revolutionibus Orbium Coelestium (On the
  Revolutions of the Celestial Spheres) on his
  death bed.
• It set forth the notion that the Earth rotates
  around the sun. (Heliocentric model). Note that
  he wasnt the first to suggest this, he was just
  the first person that anyone listened to.
• His book sparked the Scientific Revolution, a
  great leap forward in scientific discoveries and
  theories.

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Where Did Physics Start?
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Where Did Physics Start?

• Galileo The Father of Modern Physics
• Creates the telescope to further support the
  heliocentric model.
• Threw things off of the Leaning Tower of Pisa to
  show that all things accelerate downwards at the
  same rate regardless of their mass.
• In trouble with the church who supported the
  geocentric model.

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Where Did Physics Start?
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Where Did Physics Start?
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Where Did Physics Start?

• Sir Isaac Newton
• Widely regarded as the most influential scientist
  of all time.
• Three laws governing motion (Physics 30) which
  are the groundwork for classical mechanics.
• Developed a theory of colour when he noticed that
  white sunlight could be split into spectra using
  a prism
• Mathematical genius, he created calculus (at the
  same time as someone else Leibniz)
• Jerk, often people would be working on things
  that he had discovered earlier and he refused to
  share.
• He also developed the milled-edge coin to prevent
  counterfeiting.
• What do you think of when you think of Newton?

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Where Did Physics Start?
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Where did physics start?

• Marie Curie was a physicist and chemist
• she was a pioneer in the field of radioactivity,
• the only person honoured with Nobel Prizes in two
  different sciences
• the first female professor at the University of
  Paris.

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Where Did Physics Start?

• Am I missing someone?
• Who is the most famous scientist of all time?
• I will give you a hint, Time magazine declared
  him the person of the century in 1999

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Where Did Physics Start?

• Albert Einstein (1879-1955)
• The Miracle Year of Physics occurred in 1905
  when Einstein published four papers.
• His paper on Special Relativity gave us some
  amazing implications for mechanics, For example,
  now we knew that moving clocks (very fast)
  actually registered a slower passage of time.
• Finally, Einstein gave us the famous equation
  Emc2 which tells us that mass and energy are
  equivalent.

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Where Did Physics Start?

• Genius

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Is Physics Done?

• No! There are still many, many questions that we
  dont know the answer to. Some people argue if
  Physics will ever be complete.
• Perhaps the greatest goal of Physics is a Theory
  of Everything, a single set of equations that
  describe all the forces and matter in the
  universe.
• It hasnt been easy weve been looking for over
  150 years!!

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So What Can You Do As a Future Physicist?

• Ask questions!
• Try new things!
• Try to remember the questions you wanted the
  answer to when you were a child, Why is the sky
  blue?, Where do people come from (note, Im
  talking about the human race) etc.