In science there is only physics;
all the rest is stamp collecting!
• Ernest Rutherford
• (Ernest Rutherford was awarded a Nobel
Prize in Chemistry)
“Physics is at the heart of all
science”
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Allen Gandell 2003
Allen Gandell has never won a Nobel prize
BUT!!!!!!
Allen Gandell did come close to winning an
attendance award at cub scout camp!
Can you think???
• On a balance beam, we place the exact same mass
of ice on both sides such that they balance evenly.
One side is allowed to melt while the other stays
frozen by magic.
• Which way will the scale tilt and why??
• Given equal volumes of ice and water, instead of
mass, which way will it tilt??
• Hint: in what way is water a unique compound?
What was called Natural
Philosophy?
• Natural philosophy was the original name used by
the early Greek “intelligencia” to describe what
we call physics.
• It is simply an attempt to understand and describe
nature intuitively and through mathematics,
• It is amazing how much of classical
physics(nature), can be described with simple
algebra!!
AP Physics
• Mr. Gandell
• Class meets every day
all year
• If you are IB,you are
in the wrong class
Mr. Gandell
• 10th Year at Stanton
• Professional Civil/Structural Engineer
• BSCE – McGill University (cum laude)*
• MSCE- Carleton University
Grades –
st
to
rd
1 3
Nine Weeks
• 2 separate grades: AP Physics and Physics
II
• AP Physics is weighted
• Physics II is now weighted for the first time.
AP Physics Grade
• Tests only – 500 total points
• 3-4 chapter tests each 9 weeks
• Comprehensive test at end of quarter. If
higher than all of chapter tests – I will drop
the low chapter test and count the
comprehensive test twice
AP extra credit
• I have made science fair almost optional
this year
• If you decide to participate it will count for
extra credit in Physics II. This is the 1st ever
time I am allowing extra credit. I think I’m
getting old and senile!!
• Alternative: agree to tutor a physics I
student 45 min per week.
Physics II Grade
• Based on a percentage of points of
everything else: quizzes, labs, graded
assignments etc.
• There will be a lab quiz each quarter
• Labs are very important to this grade!!
• Takes special effort to fail physics II!!!
Fourth 9 Weeks
• Daily Graded Review Quizzes
• Both grades based on a percentage of all
available points. ie one test serves both
grades!
Goals
• 80-90% pass AP test
• 30% or more “5’s” on
AP Test
My Record
• 80%+ pass overall
• 99% of those that tried hard passed the
AP!!!!!!
• 100% o those who tried hard passed the AP
course!!!!!
• 99% of those who tried got an A in Physics
II. !!!!
Test Dates
• AP Test
early in May
Time flies
AP Physics
• THIS can be a very
HARD class or it can
be survivable. How?
• 3 step plan??
• Now is the time to
transfer if you are not
dedicated to passing
the AP test.
Curriculum Guide
• Refer to the
curriculum guide
• Due back no later than
Monday signed by you
and a parent
• Contract?
Handouts
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Formula Sheets
List of Constants
Critical thinking
Uncertainty lab & uncertainty definitions
This Year: Study Guide Required.
Homework
In the beginning there was only
darkness.
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Chapter 1 Review
Basic quantities and units
% error calculations vs. uncertainty
Dimensional analysis
Conversions!!!!!!!
Basic trig and math review
Do you remember???
• We measure a lot with a meter stick as 20m
x 12m.
• Precision is ± ?
• % error is ______ %
• How many sq. meters can the area be off??
Fundamental Units of SI System
• Length – Meter
• Electrical Current –
Ampere
• Mass – Kilogram
• Time – Second
• Temperature - Kelvin
• Mole: Avogadro’s # of
something
• Luminous Intensity Candela
Meter: Originally 1/ 10 millionth of
distance from North Pole to equator on
meridian through Paris
Meter
• In 1889 the distance between 2 lines
inscribed on a platinum – iridium alloy
became the standard meter
• What is the problem with this being the
standard?
• Length changes with temperature
Meter
• Today the meter is defined by the speed of
light in a vacuum.
• A meter is the distance light travels in a
vacuum in 1 / 299,792,458 seconds
What is the difference between
mass and weight?
• Mass is a measurement of the amount of
matter an object has. It gives matter a
quality called_____________??
• Weight is the result of the interaction of a
mass with a gravitational force
Mass
• SI unit of Mass is the Kilogram
• Standard kilogram is a platinum –
iridium cylinder kept in France.
• Copy number 20 is kept in USA at
National Institute of Standards and
Technology (NIST)
• Kilogram is only standard unit still
defined by an artifact
Time
• Standard unit of time is the Second
• The standard second is defined as the time
interval between the vibrations in the
cesium atom used in atomic clocks
• 1 second = 9,192,631,770 vibrations
Fundamental vs Derived Units
• We will define the other fundamental units
as we encounter them in class
• Derived units are formed from the
fundamental units
• Example: meters per second
Significant Figures
• Appropriate for things that are measured
• There is no such thing as an EXACT
measurement
• All measurements contain a degree of
uncertainty
What is the difference between
precision and accuracy?
• Precision: the degree of exactness to which
a measurement can be reproduced
• Define precision for any measuring tool?
The answer appears later. Can you find it?
• Accuracy: extent to which a measured value
agrees with the standard value of a quantity
Precision vs. Accuracy
Uncertainty
• Because the precision of all measuring devices
is limited – the number of digits that are valid
for a measurement are limited
• Example: meter stick. The smallest increment is
the millimeter. We can only estimate between
the millimeter marks, there will be some
uncertainty
• (1/2 smallest division!)
• .The last digit in a measurement is the uncertain
digit
Rules for significant figures
• Non zero digits are significant
• All final zeros after the decimal place are
significant
• Zeros between 2 other significant digits are
significant
• Zeros used solely for spacing the decimal
point are not significant
What is the difference between
an error and an uncertainty?
• An error is a mistake. Can be avoided.
• An uncertainty is a limit to the precision of a
measurement or calculation. Can’t be avoided,
only minimized.
• Significant figures reflect precision. The results of
a calculation cannot improve your precision
The quantity with the least
number of significant figures will
determine the number of
significant figures you may have
in your final answer!
Dealing with uncertainties
• Refer to the uncertainties handout.
• Remember measurements always contain a
degree of uncertainty
Dealing with Uncertainty
• To obtain a more reliable result, a physical
quantity is often measured a number of
times
• Precision deals with our ability to reproduce
measurements
Precision
• If we measure a length of a board 3 times
and got 3.21 m, 3.22 m and 3.20 m – then
our readings would be fairly precise.
• If we measured the board instead to be
3.21 m, 3.41 m and 2.81m – then our
precision would be low
Accuracy of a measurement is its
relation to its true or accepted
value
We should strive to be both
accurate and precise in the lab.
Graphing Uncertainties
• Too often students will draw a graph in a
lab write-up by simply connecting the data
points
• Due to the uncertainties of measurement,
this may prevent us from seeing the desired
relationship of the graphed physical
quantities
Graphing Uncertainties
• Data points should be marked with small circles
or crosses. The uncertainty bars should then be
added.
Graphing Uncertainties: then we
can find the best fit line
Combining Uncertainties
• Combining Uncertainties – use rules on
handout
• Ignoring uncertainties: when one of the
uncertainties is less than a quarter of the
other you can ignore it
Percent vs Absolute Error
• Absolute: real number with units.
• Eg: 3 meters + 2 cm.
• Percent : ratio of error to measure expressed
as a percent.
• Eg : (.02m/3m)x 100%
Combining Uncertainties
• Shorthand rules
add
X or ÷ only percentages add
• + or – only absolutes
•
• Pure Numbers: When you multiply or divide by
pure numbers, you multiply or divide the absolute
uncertainty by the pure number
Averaging Numbers with Uncertainties
• If the numbers share the same degree of
uncertainty, the average will have that
uncertainty
• If the numbers have different uncertainties,
follow the rules for adding uncertainties and
dividing by a pure number
Types of Coordinate Systems
• Cartesian
• Plane polar
Cartesian coordinate system
• Also called
rectangular coordinate
system
• x- and y- axes
• Points are labeled
(x,y)
Plane polar coordinate system
• (r,) Origin and
reference line are
noted
• Point is distance r
from the origin in the
direction of angle ,
ccw from reference
line
• Points are labeled
More Trigonometry
• Pythagorean Theorem
• C2 = a2 + b2
• To find an angle, you need the inverse trig
function
– for example, Θ = sin-10.707 = 450
• Be sure your calculator is set appropriately
for degrees or radians
Trigonometry Review
opposite side
sin  
hypotenuse
adjacent side
cos  
hypotenuse
opposite side
tan  
adjacent side
Problem Solving Strategy
Are Girls faster than Boys?
• Can we use a penny and paper to answer
this question?
• How accurate can we be?
• How precise can we be?
• How precise is our instrument?
• How reliable will our conclusion be?
Assignment
• You will make your own reaction
measuring tape describing how to
mathematically derive the distances
between time demarcations.
• Allotted time : due when we do
acceleration.
• You will then use your instrument to plan
and execute a lab to test your theory. Due in
1 week after handing in instrument.
continued
• Your lab should be designed to illustrate
and reinforce the understanding of
precision, accuracy, error, and how we most
often structure our procedure to minimize
error and maximize precision.
• You must also explain in detail the
fundamental equations that were used to
design the instrument.
Homework
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Read Chapter 1
Probs: AP 3,12,40,44,45
Critical thinking
Review Handout on
Uncertainties
• Lab presentation (next
slide)
• Curriculum Guides due
back NLT Friday