Journey into PhysicsCreated by Keira Favale

August 2007

Journey into Physics

Why study physics?

Career options

Areas of physics

Physicists

What is physics?

What is Physics? Of all the physical sciences, physics is the most basic and fundamental.

Physics has been described as the ‘why things work’ science as it involves discovering the rules and relationships which describe the nature of the universe. This involves everything from atoms to galaxies to the universe and everything in-between.

Even with the complexity of the world around us, one of the key ideas of physics is that there is an underlying simplicity and unity in nature. This unity does not just apply to Earth but also across the universe and throughout time.

For most of our present and future technology, physics has, or will, provide the bases for its development. Mobile phones, televisions, satellites, cameras, contact lenses, nuclear power, rockets, computers, and car design are all examples of inventions which involve the use of physics concepts. These examples highlight how interconnected physics is with modern life.

Physics provides us with a way to understand how and why things work and interact the way they do.

Home Why Study Physics?

Why Study Physics? There are many reasons to study physics. To start it is a very interesting subject,

which covers a wide range of topics including mechanics, electronics, optics, magnetism, and astronomy. But it is not just the understanding of physics concepts that can be gained from a physics course. By studying physics you have the opportunity to develop critical and creative thinking skills; skills in posing, analysing and solving questions; and the opportunity to work as a team. All of these are valuable skills which can be used throughout life.

A course in physics involves both hands on experimental investigations and theoretical analysis. Through physics we can discover how and why things work and gain a better understanding of the world around us.

The knowledge and skills gained through physics can be easy transferred into other disciplines and this adaptability can lead to a wide variety of career options.

Home Career OptionsWhat is Physics?

Career OptionsIndustries Biomedical technology Communications Computing Electronics Finance Laser/ Holograms Manufacturing Medical physics Meteorology Motor vehicle technology Photonics Power generation Research Scientific sales and management Semiconductors Teaching Telecommunications

CareersAstrophysicist BiophysicistEngineer GeophysicistParticle PhysicistPhysicist

Here are some of the many options which are available through the study of physics.

Home Why Study Physics? Areas of Physics

Areas of Physics Physical Quantities and Measurement Forces and Motion Energy and Momentum Wave Motion Optics Electricity and Electronics Magnetism and Electromagnetism Astronomy

Home Career Options Physicists

Follow the links to a range of websites to provide more information about each of these areas.

Physical Quantities and Measurement Physical Constants

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Constants

Gravity g = 9.8m/s/s

Speed of Light c = 2.998x108 m/s

Planck’s constant h = 6.626x10-34Js

Mass of electron me = 9.109x10-31kg

Mass of a proton mp= 1.673x10-27kg

Scientific notation

tera- 1012 T

giga- 109 G

mega- 106 M

kilo- 103 k

milli- 10-3 m

micro- 10-6 μ

nano- 10-9 n

pico- 10-12 p

femto- 10-15 f

astronomical unit 10-10 Ǻ

Units

Temperature – Kelvin (K) Energy – Joule (J)

Capacitance – Farad (F) Force – Newton (N)

Frequency – Hertz (Hz) Pressure – Pascal (Pa)

Forces and Motion

Explorelearning – motion and force – gizmos

Skateboard Science Mechanics with animations

and film clips Vectors – Motion and Forc

es in two dimensions Newton’s Laws

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Scalar quantities

Vector quantities

Distance (d)

Displacement (s)

Velocity (v)

Acceleration (a)

Uniform Acceleration

v = u + at

v2 = u2 + 2as

s = 1/2(u + v)t

s = ut + 1/2at2

Newton’s Laws of Motion

F = ma

W = mg

Image from: http://www.mansfieldct.org/schools/mms/staff/hand/lawsCentripetalForce_files/image008.jpg

Energy and Momentum Work, Energy and P

ower tutorial Momentum and Ene

rgy

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Kinetic energy KE = ½ mv2

Gravitational potential energy GPE = mgh

Power P = W/t

Work W = Fs cos θ

Machines – levers and pulley

Efficiency

Friction

Conservation of Momentum

Conservation of Energy

Image from: http://sol.sci.uop.edu/~jfalward/physics17/chapter3/chapter3.html

Wave Motion

Longitudinal and transverse wave motion (Dan Russell, 2006)

Explorelearning -Waves - gizmos

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Electromagnetic spectrum – visible light 400-700nm

Wavelength (λ)

Period – time of one cycle (T = 1/f = 2π/ω)

Frequency – number of cycles per unit time (f)

Angular frequency ω = 2πf

Wave speed v = λf

Simple harmonic motion – depends only on the mass (m) and force constant (k)

Standing waves – a wave that stays in the same position

Traveling waves – a wave that moves along the medium

Image from: http://uk.encarta.msn.com/media_461517875_761564098_-1_1/Types_of_Wave_Motion.html

Optics

Science, Optics and You Thin lens java applet written by

Fu-Kwun Hwang

Image formed by a converging lens

The Electromagnetic spectrum Explorelearning

– Optics - gizmos

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Object distance (u)

Image distance (v)

Focal length (f)

Snell’s Law 1/v + 1/u + 1/f

Magnification M = |v/u| = Hi (height of image)/Ho (height of object)

Ray diagrams

Angle of incidence (i)

Angle of refraction (r)

Refractive index (n)Image from: http://www.exploratorium.edu/imagery/stills/Refractive_mixing.jpg

Electricity and Electronics

Explorelearning – Electronics -gizmos

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Static Electricity – like charges repel, unlike charges attract

Electric Fields

Series and Parallel Circuits

Ohm’s Law V = IR

Kirchoff’s Laws P = VI; W=VIt

Resistance (R) – combinations in series and parallel

Conductors – charge can easily move through material

Insulators – charge can not easily move through material

P-type and N-type semiconductors

Image from: http://www.dorsetforyou.com/media/images/e/t/CompletedPrintedCircuitBoard.jpg

Magnetism and Electromagnetism

Explorelearning – Magnetism - gizmos

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Magnetic Poles – north-seeking and south-seeking

Magnetic fields – permanent magnets, current carrying wires, loops, solenoid

Magnetic Flux – the number of magnetic field lines passing through a surface

B = kI/r; B = 2πkNI

Units – tesla (one newton per ampere per meter),

EMF is proportional to the rate of change of magnetic flux (Φ)

EMF = BLv; EMF = -NΔΦ/Δt

Generators and TransformersImage from: http://en.wikipedia.org/wiki/Magnetism

Astronomy

Introduction to the sky Main Sequence Stars

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The expanding universe

Background radiation

Black holes

Stars, Planets and Galaxies

Kepler’s Laws 1. Each planet moves in an elliptical orbit, with the sun at one

focus of the ellipse

2. A line from the sun to a given planet sweeps out equal areas in equal time

3. The periods of the planets are proportional to the 3/2 powers of the major axis lenghts of their orbits

Image from: http://solar.physics.montana.edu/gallery/intro.html

Physicists Marie Curie Albert Einstein Michael Faraday Stephen Hawking James Maxwell Isaac Newton

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Follow the links to a range of websites which cover the life and achievements of each of these physicists.

Marie Curie (7/11/1867 – 4/07/1934)

Marie Sklodowska Curie Biography Marie and Pierre Curie a

nd the Discovery of Polonium and Radium

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Image from: http://hep.ucsb.edu/people/hnn/mcurie.jpg

Nobel Prize in Physics 1903 – awarded to Marie and Pierre Curie for the discovery of radium and polonium; award was shared with Antoine Henri Bacquerel (discovered natural radioactivity)

Nobel Prize in Chemistry 1911 – awarded to Marie Curie for isolating radium and studying its chemical

properties

Throughout the First World War, Marie Curie was engaged intensively in equipping more than 20 vans that acted as mobile field hospitals and about 200 fixed installations with X-ray apparatus

Albert Einstein (14/03/1879 – 18/04/1955)

Biography Einstein – Image and Impact

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Nobel Prize in Physics 1921 – for his services in Theoretical Physics, and his discovery of the law of the photoelectric effect

The Photoelectric Effect – Einstein postulated that a beam of light consists of small packages of energy called photons or quanta – E = hf = hc/λ

Special Theory of RelativityFirst Postulate – Principle of relativity: The laws of physics are the same in every inertial frame of reference

Second Postulate – The speed of light in a vacuum is the same in all inertial frames of reference and is independent of the motion of the source

Implications: (1) Events that are simultaneous for one observer may not be simultaneous for another (2) When two observers moving relative to each other measure a time interval or a length, they may not get the same results

Image from: http://hep.ucsb.edu/people/hnn/Albert_Einstein.jpg

Previous

Michael Faraday (22/09/1791 – 25/08/1867)

Michael Faraday Faraday

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First introduced the concept of field lines (electric field lines)

Faraday’s icepail experiment – based on the same principle is used in a Van de Graaff electrostatic generator and forms the basis for electrostatic shielding

Faraday and Henry discovered that moving a magnet near a conducting loop can cause a current in the loop

Faraday’s Law of induction: the induced EMF in a closed loop equals the negative of the time rate of change of magnetic flux through the loop

Image from: http://www.abdn.ac.uk/~u02rjr4/px2013/Faraday.htm

Stephen Hawking (8/01/1942)

Official Website

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With Roger Penrose, Hawking showed that Einstein's General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes.

Hawking discovered that black holes should not be completely black, but should emit radiation and eventually evaporate and disappear.

Another conjecture he has made is that the universe has no edge or boundary in imaginary time.

Image from: http://hep.ucsb.edu/people/hnn/hawking.jpg

Next

James Maxwell (13/06/1831 – 5/11/1879)

Maxwell Year 2006 James Clerk Maxwell: a force for physics

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The first person to truly understand the fundamental nature of light

Discovered the basic principles of electromagnetism – Maxwell’s Equations

Displacement current iD – electromagnetic theory

Image from: http://hep.ucsb.edu/people/hnn/maxwell.jpg

Isaac Newton (25/12/1642 – 20/03/1727)

Newton, Isaac Sir Isaac Newton

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Newton’s Laws of Motion – foundation of classical mechanics (or Newtonian mechanics)

First Law – An object that is at rest will remain at rest or an object that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on that object is zero.

Second Law – The force of an object is equal to the mass of an object multiplied by its acceleration (F=ma)

Third Law – All forces come in pairs and these two forces are equal in magnitude and opposite in direction (equal and opposite)

Newton’s Law of Gravitation F = G mAmB

d2

Image from: http://hep.ucsb.edu/people/hnn/newton_1.jpg

Finish

Only just the beginning… This is only a brief

introduction to the amazing journey through Physics. For more information about Physics courses contact your science teacher, guidance officer, or choice of university.

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