Friday, February 25, 2011

Friday, Feb 25, 2011

Collected Ball and Soap Labs

Introduction to Heat, Temperature, and Thermodynamics

Handed out note packets from Tsokos sections 3.1-2

Definitions of Temperature, Heat, Internal Energy
Demo of hands in water
Temperature scales
Heating curve
Heat capacity and specific heat capacity
Latent heats

Calorimetry problems - heat lost = heat gained

Asked students to do reading assignment question pages in packet
Try problems in Thermal Energy packet
Do problems at end of section in text book

Wednesday, February 23, 2011

Wednesday, Feb 23, 2100

Gave several problems from IB Physics 1 for review:
Rocket problems
Projectile motion problems
Inclined plane problems
Geosynchronous orbit problem

Showed how to get gravitational potential energy
Used this equation to calculate escape velocities and size of Earth if Earth were black hole

Tuesday, Feb 22, 2011

Thinking Physics answer cards

Friday, Feb 18, 2011

I was sick
Students got laptops and worked on Ball and Soap Lab

Thursday, Feb 17, 2011

Wednesday, Feb 16, 2011

Tuesday, Feb 15, 2011

Monday, Feb 14, 2011

Friday, Feb 11, 2011

Tuesday, February 8, 2011

Thurs Feb 10, 2011

Oleic Acid Lab for IB data collection, data analysis, conclusions

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

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

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.