Physical Science 15

“Magnetism, as you recall from physics class, is a powerful force that causes certain items to be attracted to refrigerators.” - Dave Barry

Your discussion post about the lab questions is due by Tuesday, 10/21 on Blackboard by 11:55 PM PDT.

Your lab report is due at our next on-campus lab meeting (Wednesday, 10/29 or Thursday 10/30).

Our next lab involves more sophisticated experimental techniques that illustrate again how scientists will often do multiple, different experiments to determine a value or process. As you have seen in our class, every measurement carries with it some inherent uncertainty, in how you read the instruments you have at your disposal, and their own internal limitations on precision. Together, these measurement and experimental uncertainties can limit your overall accuracy - whether you determine the "right" answer, close to Nature's truth - and your precision - how specific you can be determining that answer.

Lab #8 Process:

1. The lab procedure is laid out in the attached document. Note that you will need to MEASURE values carefully, RECORD them neatly, and then ANALYZE your experiment for sources of error and uncertainty.

Your lab report should include responses to all of the questions in the lab, as well as the data itself. For this lab, while you are welcome to collaborate with others in the class, please submit your own individual report. Aim for at least 2 pages here, typed. Bring the lab report to our next on-campus lab, or if you prefer, email it to me within Blackboard as a message, not as an attachment. Please don't post your lab report in the discussion forum.

2. Read the following short articles:

Mosher, D. (2007, 26 September) Birds May See Earth's Magnetic Fields. Live Science. Accessed 10/13/08 from http://www.livescience.com/animals/070926_birds_see_magnetism.html.

Levy, S. (1999) Navigating With A Built-In Compass. National Wildlife. Oct/Nov 1999 Vol 37. no 6. National Wildlife Federation. Accessed 10/13/08 from http://www.nwf.org/nationalwildlife/article.cfm?articleId=682&issueId=26

3.. POST your response to this final questions in the discussion area for the labs, and read and comment upon the posts of others:

What experiments would you suggest scientists try to determine how birds use the Earth's magnetic field - if at all - in migration? What are some of the sources of error and uncertainty in your experiment(s)?

Going Further: Extra Credit Post your essays for any of these in the Blackboard discussion forum for this Lab.

Explore the following scientific article about possible links between bird migration and magnetite:

Wiltschko, W. et. al. (2006, August 8) Bird navigation: what type of information does the magnetite-based receptor provide? Proc Biol Sci. 2006 November 22; 273(1603): 2815–2820. The Royal Society. Accessed 10/13/08 from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1664630

Comment on the article, and the processes of science you detect (observation, research, development of hypotheses, experiments, analysis for error and alternative possible explanations, further experiments).
Look for additional scientific articles on the subject, and share your thoughts on how they add to our knowledge. Provide a complete bibliography.

“I believe that there is a subtle magnetism in Nature, which, if we unconsciously yield to it, will direct us aright. It is not indifferent to us which way we walk.
There is a right way; but we are very liable from heedlessness and stupidity to take the wrong one.
We would fain take that walk, never yet taken by us through this actual world, which is perfectly symbolical of the path which we love to travel in the interior and ideal world; and sometimes, no doubt, we find it difficult to choose our direction, because it does not yet exist distinctly in our idea.”

-Henry David Thoreau