Powers of Ten

Hi all,

For homework tonight, please watch online the short video "Powers of Ten", which can be found here: http://www.powersof10.com/index.php?mod=register_film. You need to provide your e-mail in order to view the film. If you don't want to do that, look it up on YouTube - it's there.

After you watch the video, please respond to these questions on a single side of a large index card.

1. What's the best metric unit (meters, millimeters, micrometers, etc.) to measure the following items: (a) atoms (b) a skin cell (c) bacteria cells (d) viruses (e) mitochondria (f) width of a human hair (g) a DNA molecule (h) an atom

2. Why do you think are cells so small? Is there an advantage?

This is due tomorrow. Happy watching.
-Mr. Hill

First lab

By this time, both classes have completed our first lab.  The task was to observe a cork cell under the microscope, draw it, and then determine how much larger the drawing was compared to the "real" cell.

All groups in all periods were successful at devising a way to measure the actual cell - and remarkably, many of you figured out different ways of doing it that were plausible.  The most common techniques I noticed were:

1. measuring the pointer and using a ratio 
2. measuring the image of the cell in the eyepiece and then working backwards using the magnification
3. measuring the diameter of the field of view and estimating how many cells could fit across the diameter

Well done Class II.  Take note of how much you can accomplish without much direction from me.

Homework

For both classes, your next homework is due Thursday, 9/17.  You are to complete the four magnification questions on the handout given in class (I do not have an electronic copy - hope you didn't lose it!)  Note that these are your first taste of IB-style test questions.  Also, one of these problems could be used as a sample calculation for your assessment statement 2.1.5, regarding magnification.

Best,

Mr. Hill 

Classroom resources

Today, we worked in groups to examine the "tools of the trade" are available to help them with the considerable workload to follow in IB Biology.

Homework for Monday, September 14th: Complete the online microscope pre-activities in preparation for our first use of the microscope in lab this week.  Please go go to this website, courtesy of the University of Deleware, that offers you two resources: a video introduction to the microscope, and a virtual microscope that you can manipulate and use.  This will help you sharpen your scope skills in preparation for the real thing.  Using these resources, please complete the pre-lab handed out in class.  If you lost it or were absent, the worksheet can be downloaded below.

Microscope pre-lab worksheet

Have a wonderful weekend!
-Mr. Hill