Monday, September 17, 2007
Mon-day 1
Bio- we discussed the eight different life processes common to all organisms and noted the KEY TERMS that are associated with each process.
We then finished the microscope lab (here is a copy for those of you who needed one today) in which we noted the orientation of the image through the lens system (upside down and reversed!) as compared to the orientation of the image on the slide. We learned how to place a cover slip over the specimen on the slide so as to avoid air bubble formation. We also saw how to apply a drop of stain/pigment so that it seeps under the cover slip.
We will review "field of view" and do some calculations involving that, tomorrow.
The most COMMON ERROR that students made today was when they went from low power (10x) to high power (40x) objectives and THEN used the COARSE ADJUSTMENT! That is expressly forbidden and can ruin the lenses and the slide, as explained in class. To repeat, ONCE you have the sample focused at low power, it will ALSO automatically be focused at HIGH POWER; the only slight adjustment after the switch to high power is to just BARELY turn the FINE ADJUSTMENT knob and, possibly, to rotate the diaphragm wheel to let in more light. THAT'S IT!
Tomorrow, I will collect the textbook section 1.2 outline. Your outline must be as thorough as the model outline (section 1.1 that I gave to you), it must be handwritten (not typed), and it must be VERY neat (so that you can easily study from it). If you hand in the outline late, points will be deducted for each day the assignment is overdue.
Chem 7- we continued our lesson with scientific notation (numbers must agree first to the number of sig figs and second to the same value) and then went on to some unit conversion practice.
Just in case, a copy of the worksheet that we have been working on in class can be found in Blackboard under "Cicale's Assignments". Try this link , then click on "Assignments" (on the left) and scroll down to "Cicale's Assignments" and look for "Matter and Lab Basics Classwork".
Chem 8/9- we covered scientific notation, unit conversion, and calculations with significant figures.
We then did a density measurement lab during which the most common question was:
"How can the beaker with twenty mL of water not be the same as the graduated cylinder with twenty mL of water?"
THAT'S THE WHOLE POINT of using significant figures in measurement! The beaker was marked to the TENS of milliliters whereas the graduated cylinder, a more PRECISE measuring tool, was marked to the milliliter. So 20 (no decimal) mL is the best you can estimate with the beaker (the "0" in 20 is a visual guess) BUT 20.4 mL could be your best estimate with the graduated cylinder (the "4" in 20.4 is a visual guess) even if they both contained the EXACT same amount of water.
We then finished the microscope lab (here is a copy for those of you who needed one today) in which we noted the orientation of the image through the lens system (upside down and reversed!) as compared to the orientation of the image on the slide. We learned how to place a cover slip over the specimen on the slide so as to avoid air bubble formation. We also saw how to apply a drop of stain/pigment so that it seeps under the cover slip.
We will review "field of view" and do some calculations involving that, tomorrow.
The most COMMON ERROR that students made today was when they went from low power (10x) to high power (40x) objectives and THEN used the COARSE ADJUSTMENT! That is expressly forbidden and can ruin the lenses and the slide, as explained in class. To repeat, ONCE you have the sample focused at low power, it will ALSO automatically be focused at HIGH POWER; the only slight adjustment after the switch to high power is to just BARELY turn the FINE ADJUSTMENT knob and, possibly, to rotate the diaphragm wheel to let in more light. THAT'S IT!
Tomorrow, I will collect the textbook section 1.2 outline. Your outline must be as thorough as the model outline (section 1.1 that I gave to you), it must be handwritten (not typed), and it must be VERY neat (so that you can easily study from it). If you hand in the outline late, points will be deducted for each day the assignment is overdue.
Chem 7- we continued our lesson with scientific notation (numbers must agree first to the number of sig figs and second to the same value) and then went on to some unit conversion practice.
Just in case, a copy of the worksheet that we have been working on in class can be found in Blackboard under "Cicale's Assignments". Try this link , then click on "Assignments" (on the left) and scroll down to "Cicale's Assignments" and look for "Matter and Lab Basics Classwork".
Chem 8/9- we covered scientific notation, unit conversion, and calculations with significant figures.
We then did a density measurement lab during which the most common question was:
"How can the beaker with twenty mL of water not be the same as the graduated cylinder with twenty mL of water?"
THAT'S THE WHOLE POINT of using significant figures in measurement! The beaker was marked to the TENS of milliliters whereas the graduated cylinder, a more PRECISE measuring tool, was marked to the milliliter. So 20 (no decimal) mL is the best you can estimate with the beaker (the "0" in 20 is a visual guess) BUT 20.4 mL could be your best estimate with the graduated cylinder (the "4" in 20.4 is a visual guess) even if they both contained the EXACT same amount of water.
# posted by C @ 11:13 AM 
