Tuesday, February 8, 2011
Wed Feb 9, 2011
Ask if any problems or questions on worksheet or Quia
Did Uncertainty Quiz in class
Students do BB lab
Explained the various uncertainties involved
Students checked calculations on laptops
HW - Try Quia on Uncertainties again
Did Uncertainty Quiz in class
Students do BB lab
Explained the various uncertainties involved
Students checked calculations on laptops
HW - Try Quia on Uncertainties again
Monday, February 7, 2011
Tues Feb 8, 2011
HW for tomorrow:
Do problem sheet on uncertainty (omit min max)
Do Quia on uncertainty
Check for textbook covers.
Collect Parent Notification Forms
Collect Course Expectation Forms
Chastised students for not putting on covers or doing Quia
Students wrote density measurements on board:
Block Mass(g) Length(cm) Width(cm) Height(cm) Density(g/cm^3)
Are they the same? How close do they have to be to be considered the same?
All the blocks were made of the same material, Aluminum.
How can we tell if the measurements are "good enough"
Hand out Flow Chart 1.2
Random Errors
Show how to calculate the uncertainty for several measurements
unc = sum(|meas - avg)|/# measurements
We did this in the Measurement and Graphing Lab of IB Physics 1 (Diameter vs Circumference)
If all measurements are the same, uncertainty is 1/2 the reading error
Rules for uncertainty:
1. At most 2 sig figs in uncertainty
2. Quantity then has the same number of decimal places as uncertainty
Reading errors
1. For analog devices, uncertainty is 1/2 the scale division...but, you often have this same uncertainty at each end of a ruler so the uncertainty in the length is the scale division
2. For digital devices, uncertainty is scale division
Adding or subtracting quantities:
If you add or subtract values, you add the absolute uncertainties.
Showed example of finding perimeter of circle.
Method of Relative Uncertainty:
Derived the relative uncertainty equation for a rectangle.
Used this equation in several examples: Area of square, volume of sphere
Showed that the absolute value of the exponent becomes the coefficient for the relative uncertainty.
Did a weird example: Q = A^2 * B^(5/3) * C^(-10)/D^(3/7)
unc Q = Q * 2*uncA/A + (5/3)*uncB/B + 10*uncC/C + (3/7)*uncD/D
Using Excel for uncertainty calculations:
Students got laptops and pulled up Excel spreadsheet
Entered in headers and then data from density lab
Calculated density and uncertainty and wrote using correct number of significant digits.
Handed out notes and problems on uncertainty
HW students work these problems (except max min problems)
Do Quia on uncertainty
Do problem sheet on uncertainty (omit min max)
Do Quia on uncertainty
Check for textbook covers.
Collect Parent Notification Forms
Collect Course Expectation Forms
Chastised students for not putting on covers or doing Quia
Students wrote density measurements on board:
Block Mass(g) Length(cm) Width(cm) Height(cm) Density(g/cm^3)
Are they the same? How close do they have to be to be considered the same?
All the blocks were made of the same material, Aluminum.
How can we tell if the measurements are "good enough"
Hand out Flow Chart 1.2
Random Errors
Show how to calculate the uncertainty for several measurements
unc = sum(|meas - avg)|/# measurements
We did this in the Measurement and Graphing Lab of IB Physics 1 (Diameter vs Circumference)
If all measurements are the same, uncertainty is 1/2 the reading error
Rules for uncertainty:
1. At most 2 sig figs in uncertainty
2. Quantity then has the same number of decimal places as uncertainty
Reading errors
1. For analog devices, uncertainty is 1/2 the scale division...but, you often have this same uncertainty at each end of a ruler so the uncertainty in the length is the scale division
2. For digital devices, uncertainty is scale division
Adding or subtracting quantities:
If you add or subtract values, you add the absolute uncertainties.
Showed example of finding perimeter of circle.
Method of Relative Uncertainty:
Derived the relative uncertainty equation for a rectangle.
Used this equation in several examples: Area of square, volume of sphere
Showed that the absolute value of the exponent becomes the coefficient for the relative uncertainty.
Did a weird example: Q = A^2 * B^(5/3) * C^(-10)/D^(3/7)
unc Q = Q * 2*uncA/A + (5/3)*uncB/B + 10*uncC/C + (3/7)*uncD/D
Using Excel for uncertainty calculations:
Students got laptops and pulled up Excel spreadsheet
Entered in headers and then data from density lab
Calculated density and uncertainty and wrote using correct number of significant digits.
Handed out notes and problems on uncertainty
HW students work these problems (except max min problems)
Do Quia on uncertainty
Monday Feb 7, 2010
HW due tomorrow:
Hand in signed course expectation form
Hand in signed Parent Notification form
Cover both textbooks
Do Quia quiz on A1 General Knowledge
Hand out:
Student Profile - Students complete and put in bin for 10 pts
Course Expectation Form
Student and Parent Form for Course Expectations - students return for 5 pts
Parent Notification Form - Students return one signed copy for 10 pts. (Keep the other at home since it has my contact info)
Hand out Tsokos books
Go over Expectation Form
Hand out Quia Passwords
Assign Quia Quiz on A1 - General Knowledge
Hand out flowchart 1.1
Get Hewitt textbooks
Go over rapid estimation problem of how many atoms are in the Sun
First asked for guestimates on answer.
Used circumference of Earth from definition of meter
Used diameter of Sun since ~100 Earths span the Sun
Derived tidal equation - used fact that Moon just covers Earth in total eclipse to show, for Moon and Earth that ratio of diameter to distance is the same. Ratio of tidal forces becomes ratio of densities. Moon is rock. Moon's effect on tides ~ 2.2 times that of Sun so density ~ 2.2 times that of Sun. Use density of Sun to be about 1.
Used value of mole to calculate number of atoms in Sun.
Introduction to uncertainties:
Handed out a block of aluminum to each student and asked them to find the density of that piece of metal.
Hand in signed course expectation form
Hand in signed Parent Notification form
Cover both textbooks
Do Quia quiz on A1 General Knowledge
Hand out:
Student Profile - Students complete and put in bin for 10 pts
Course Expectation Form
Student and Parent Form for Course Expectations - students return for 5 pts
Parent Notification Form - Students return one signed copy for 10 pts. (Keep the other at home since it has my contact info)
Hand out Tsokos books
Go over Expectation Form
Hand out Quia Passwords
Assign Quia Quiz on A1 - General Knowledge
Hand out flowchart 1.1
Get Hewitt textbooks
Go over rapid estimation problem of how many atoms are in the Sun
First asked for guestimates on answer.
Used circumference of Earth from definition of meter
Used diameter of Sun since ~100 Earths span the Sun
Derived tidal equation - used fact that Moon just covers Earth in total eclipse to show, for Moon and Earth that ratio of diameter to distance is the same. Ratio of tidal forces becomes ratio of densities. Moon is rock. Moon's effect on tides ~ 2.2 times that of Sun so density ~ 2.2 times that of Sun. Use density of Sun to be about 1.
Used value of mole to calculate number of atoms in Sun.
Introduction to uncertainties:
Handed out a block of aluminum to each student and asked them to find the density of that piece of metal.
Friday, January 22, 2010
Friday, Jan 22, 2010
Quiz on Standing Waves
Students finished work on labs: Waves on a string, waves in a pipe, and Tones and Telephones. Lab write-ups are due on Tuesday.
For Waves on a String I'm looking for computer generated graphs showing linear trends with slopes and uncertainties in slopes where possible. Students will make graphs of frequency vs # of segments and also show a linear graph relating tension and velocity.
Data: mass (g) velocity (m/s)
250 33.3
350 37.5, 39.55
450 45.7
550 48.72
As a hint, also asked students to calculate the mass per unit length of the string.
For Waves in a Pipe lab, I want a graph of depths vs resonance number
For Tones and Telephones, I just need the results of the telephone signals
Handed out RA 28.1, RA 28.2 also due Tuesday
Students finished work on labs: Waves on a string, waves in a pipe, and Tones and Telephones. Lab write-ups are due on Tuesday.
For Waves on a String I'm looking for computer generated graphs showing linear trends with slopes and uncertainties in slopes where possible. Students will make graphs of frequency vs # of segments and also show a linear graph relating tension and velocity.
Data: mass (g) velocity (m/s)
250 33.3
350 37.5, 39.55
450 45.7
550 48.72
As a hint, also asked students to calculate the mass per unit length of the string.
For Waves in a Pipe lab, I want a graph of depths vs resonance number
For Tones and Telephones, I just need the results of the telephone signals
Handed out RA 28.1, RA 28.2 also due Tuesday
Wednesday, January 20, 2010
Wed, Jan 20, 2010
Collected RA 18.2
Handed back Labs on Snell's Law, Speed of Sound in Air
Answered questions
Answered questions on standing waves homework
Explained labs
Students did Waves on a String Lab
Waves in a Pipe Lab
Tones, Vowels, and Telephones
Labs due Jan 26
Handed back Labs on Snell's Law, Speed of Sound in Air
Answered questions
Answered questions on standing waves homework
Explained labs
Students did Waves on a String Lab
Waves in a Pipe Lab
Tones, Vowels, and Telephones
Labs due Jan 26
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