Thursday, Feb 5, 2009 - Block 3

Told students that next Wednesday I plan to have them do a major IB lab - what are the various factors that affect the period of a pendulum? They will have to think of how to do this using the Vernier equipment.

Asked if there were any questions on the IB Physics 1 review problems. There were none.

Went over uncertainties. Students measured length and width of a table top and estimated the uncertainties in each measurement.
Calculated the perimeter and its uncertainty. If you add or subtract quantities, you ADD the absolute uncertainty to get the uncertainty in the result.

After you get the uncertainty, this determines how you display your result. You can have AT MOST 2 sig figs in the uncertainty and then the number of decimal places in the uncertainty is the same as the number of decimal places in the result.

Showed how to calculate the area and uncertainty in the area using the min-max method and the method of relative uncertainty.

Students did the BB Pancake Lab.
I demonstrated how to use an micrometer so they could actually measure the diameter of the BB.
I set up a computer with an Excel spreadsheet so they could input their data table and check their answers with uncertainty.

Handed RA 10 due tomorrow. Handed out a worksheet on uncertainties due on Monday. Along with the worksheet I handed out the print of an excel program for them to input their answers.