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Physics 1
Learning Physics
 In our School: courses FY01-FY07+FY08 +FY-FY11
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FY01-03 (1. y); FY03-FY06 (2. y); FY07 (3.y);
FY08 (preparing to matriculation examination, 3. y)
FY9 (project course)
FY10 (eximia course)
Further studies in Universities
Occupations
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Physicians (research work)
Engineers
Medicine (doctors, ..)
Teachers (upper sec, vocational s, universities, institutions)
Physics 1
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Physics
exact Natural Science
 learns Us to understand Natural Phenomena
 experimental science (Empirical),
 measuring as accurate as possible, making
Mathematical models (Exact Science) and
formulas and having Theorethical discuss.
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Physics 1
Historical overwiew
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Natural Philosophy
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Ancient Science
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Astronomy
Astronomy
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400BC
beginning of Science at 1500BC,
philosophical thinking and discussing
Pythagoras 500BC, Platon 400BC, Aristotle 250BC: Earth, Fire, Water, Air, Ether
Early Middle Age Science
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2900BC
Astronomy, Sun and Moon, planets
technical devices: hunting, fishing, agriculture, building
Antic Science
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Timeline
Astronomy, Alchemy, Mathematics
respect of Aristotle: Earth is in the middle
Alchemistry: ancient art of obscure origin that sought to transform
base metals (e.g., lead) into silver and gold; forerunner of the science
of chemistry
Universities arise in Italy, France, Spain and England in the late
11th and the 12th centuries for the study of arts, law, medicine, and
theology
Copernikus 1500 Renaissance astronomer and the first person to
formulate a comprehensive heliocentric cosmology which displaced
the Earth from the center of the universe.
1100
Physics 1
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Classical Physics
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1500-
Research became important
ENERGY thinking arises
Thermometer, electric phenomena, speed of light is constant, X-rays
Different parts of Physics have connections to each other
Galilei 1564-1642: Beginning of Classical Physics
Newton 1642-1727: Law of Gravitation: Principia Mathematica Philosophie
Naturalis
Ampere 1775-1836: connection between electricity and magnetism
Mechanics
Thermal Physics
Wave Motion
Acoustics
Light and Optics
Electricity and Magnetism
Physics 1
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Modern Physics
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Classical Physics could not explain the atomic structure of the matter
The basic particles of the matter have both particle- and waveform
(Dualism)
E=mc2
Laws of Mechanics are working when the velocity is small
Albert Einstein, Theory of relativity:
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1900-
The speed of light in vacuum is constant (c=2,99792458*108 m/s)
All motion is relative. The spectator can not determine by Physical
experiment, if he/she is in rest or in constant, direct motion.
Edwin Hubble 1924: there exists other galaxies than Milky Way
Wilhelm Röntgen X-rays
Marie Curie
Radioactivity
Physics 1
Parts of Physics
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Mechanics
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Thermal Physics
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Mirrors, Lenses, Optical devices, Light in different matters and boundaries, Diffraction
Electromagnetism
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Sound waves, Technical devices
Optics
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Temperature, Thermal Energy, Phases, Thermal Machines
Acoustics
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Motion of particles, balance of particles: Measuring, Velocity, Force, Acceleration, Force and Motion,
Newton’s laws, Energy, ….
On of the most important part of Physics: Galileo, Newton
Electricity, Magnetism, Electric Charge and Current, Resistance, Electric
Potential, Power
Electric and Magnetic Field, Generators, Electric motors
Modern Physics
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Theory of Relativity
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Gravitation, structure of time-space
Quantum Mechanics
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Structure of Atoms, Radioactivity, Nuclear Physics
Physics 1
Measuring and measuring accuracy
Quantity (=suure)
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Quality of particle or material that can be measured
Quantity= numerical value * unit
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Example: speed = 90 km/h; length = 285,4 m; time = 0,4 s
Physics 1
Measuring and accuracy
There is uncertainty associated with every measurement,
and the Uncertainty arises from different sources:
• the limited accuracy of every measuring instrument,
• when reading the instrument,
• the measuring instrument is affecting the
circumstances,
• marking errors etc.
NOTICE
•the result of a measurement is an approximation.
•if you measure the value of the quantity many times, you
get a group of results, from where you can decide the most
likely value for the unit.
Physics 1
Error types when measuring
Rough error
Systematic error
Occasional error
NOTICE
•the result of a measurement is an approximation.
•if you measure the value of the quantity many times, you
get a group of results, from where you can decide the most
likely value for the unit.
Physics 1
Calculations in Physics
All the measuring results are approximations (not
”exact”), so we must approximate the answers with
certain rules.
The rules are different in the cases where we have just
adding/substracting or also multipliying/dividing in the
formula.
Definition
Significant numbers (merkitsevät numerot)
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All numbers are significant except
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zeros at the end of an integer (mostly)
Zeros at the beginning of a decimal number
Examples
Tell the Amount of Significant Numbers
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7,60 s
0,0867 m
100g
200 MB
1,51.106 m
Physics 1
Digits in calculations
When making measurements, or when doing calculations, you should avoid the temptation to keep more digits in
the final answer than is justified (or allowed).
6,8
Multiplying and dividing
11,3
Example:
The area of rectangle (These are measuring results!)
Length=6,8cm
A1=6,7x11,2=75,04
Height=11.3 cm
Area A= 76,84 cm2
A2=6,9x11,4=78,66
The real area is between 75,04 and 78,66, so you cannot use the precision of
0,01cm2. The best answer should be 77cm2 and the uncertainty is 1-2 cm2 . The two
digits must be dropped, because those are not significant digits.
The final result of multiplication or division should have
only as many digits as the number with the least number
of significant figures (numbers) used in the calculation.
Physics 1
Digits in calculations
Adding and subtracting
Example:
Measuring results of length are 7,56 cm and 3,6 cm. The sum is 11,16 cm but it is not right to use
the accuracy of 0,01. At the end of calculation you must approximate the result to 11,2cm.
The final result cannot be more accurate than the least accurate number used. Here we count the
least accurate number with decimals (how many numbers is after decimal point).
The final result of addition or subtraction should
have only as many digits after the decimal point
as the number with the least number of digits
after decimal point used in the calculation.
Physics 1
Measuring devices for length
Historical:
Scale (weight)
Ruler, Caliper ruler (length, thickness)
Micrometer screw (thickness)
Modern:
Laser (length)
Ultrahigh sound (thickness)
and for time
Stopwatch vs. Lightports
Examples
Measuring of length
Measuring of time
Q Is possible to make the uncertainty of the
measurement smaller?
Physics 1
Measured quantity x can be given in form
x = xm +Δx
where
xm= result of measurement
Δx= absolute error due to the used device (uncertainty)
The accurate result of the measurement is between
xm + Δx and xm – Δx.
Physics 1
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Example 1
Is the diamond yours?
A Friend asks you to borrow your precious
diamond for a day to show her family. You are a
bit worried so you carefully have your diamond
weighted on a scale which reads 8,17g. The
scale’s accuracy is claimed to be +0,05g. The
next day you weigh the returned diamond
again, getting 8,09g. Is it your diamond?
Physics 1
Error analysis in experiments
Mathematical analysis with the average deviation
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Count the average value of measuring results
Count the absolute deviation of each measuring result AND with
these count the Average absolute deviation
Count the av
The result with errorlimits is then
AVERAGE VALUE +-AVERAGE absolute DEVIATION
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Verbal Analysis of the uncertainty
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the limited accuracy of every measuring instrument, when
reading the instrument, the measuring instrument is
affecting the circumstances, marking errors etc.
Measuring and error limits
Physics 1
Measuring and Work report
Physics is experimental science. After making experiments we also make work
reports from the research.
The contents of the work report is following (example)
 the theory of the phenomena
 choosing the measuring target
 measuring plan, devices and methods in the research
 results of measurements
 results and a graphic illustration
 estimation of error
 the study of the work and results
Physics 1
SI-system
 accepted in Finland 1975
 International agreement of Quantities and Units which
are used
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Basic Quantities and Units
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Derived Quantities and Units
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Definition of standard units
Derived from basic units
Additional Quantities and Units
Prefixes
Physics 1
SI basic quantities
and units
SI base unit
SI Base quantity, symbol Name Symbol
length, l or s
meter
m
mass, m
kilogram kg
time, t
second s
electric current, I
ampere A
thermodynamic
temperature , T
kelvin
K
amount of substance, n
mole
mol
luminous intensity, I
candela cd
SI quantities and the definions of the Quantities can be found from your
Tablebook (MAOL)
Physics 1
Units outside the SI
•additional units
•here you can see
some exampels
•more from your
MAOL
Physics 1
SI derived quantities and units
•Other quantities, called derived quantities, are defined in
terms of the seven base quantities via a system of quantity
equations.
•The SI derived units for these derived quantities are
obtained from these equations and the seven SI base
units.
Physics 1
Examples of SI derived units
SI derived unit
Derived quantity
Name
Symbol
area
square meter
m2
volume
cubic meter
m3
speed, velocity
meter per second
m/s
acceleration
meter per second squared
m/s2
density
kilogram per cubic meter
kg/m3
amount-of-substance
concentration
mole per cubic meter
mol/m3
luminance
candela per square meter
cd/m2
Physics 1
Counting with Quantities
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From quantity equations you can find equation for the asked
quantity
Ex1. Force F, body mass m and aceeleration a are depending from
each other by equation F=ma.
Make equation for counting m and a.
Ex2. Equation s=vt are telling how trip, velocityand time are
depending from each other.
A car is travelling 58km in 50 minutes. Count the average speed of
the car.