And You Thought Your Parents Were Tough

The Importance of Proper Engineering

Ok, Ok

Despite the fact that it made more work for both me and the secretary, I added one point to your final exam grades. The net result - no change in your final grade for the year. None, not one bit. As I said in class, that one point, when calculated into the whole year was insignificant, but so many people were convinced that it would somehow salvage their averages, I went ahead and did it, primarily to demonstrate that it would not. Here's a hint for next year and for the rest of high school. Do not quibble or worry about a point here or there - it doesn't make any difference. Even when it seems like it does for a single test, that one test is only one grade that factors into your entire year's body of work. If you focus too much on that type of thing, it usually indicates that you are not concentrating on the big picture - did you do very well, well, average, below average or poor. Don't fret over the individual points, fret over your overall performance and work to maximize that.

Have a safe and fun summer - it is a short one this year so make the most of it! I'll post things here now and then of scientific/science fiction interest so check in periodically to see what I'm thinking about...

Tomorrow, It Begins

Final exams begin tomorrow afternoon, so I wish everyone good luck!

Physics and Honors Physics are completing all final bits and pieces of their laboratory unit. Once individuals submit their lab packets, their responsibilities are over and they can use any remaining class time to study for exams.

Physical Science had its last discussion of atoms and the periodic table. The properties of isotopes and uses of radioisotopes were examined, as were the differences in metallic properties of elements. As for elements, people often wonder where the elements get their names. Here is a good website for that information:


History of the Origin of the Chemical Elements and Their Discoverers

Counting Down

Physics and Honors Physics are nearly done with their lab unit and most everyone should finish up tomorrow. On Wednesday, students may use the class period to prepare for their G-Block exam.

Physical Science got whisked through the wacky world of ions and completed their tour of the periodic table. Tomorrow, we will discuss isotopes and how metallic properties vary across the elements. On Wednesday, we will tidy up any loose ends for this final unit and address any questions before Monday's final exam. Since it is a cumulative exam, the experience of taking the MCAS should serve as excellent review. Use your MCAS review materials, note packages, old tests/labs and textbook to prepare.

Puzzles Are Fun

I put a little widget at the bottom of the blog that allows you to input the URL of any .jpg and turn it into a jigsaw puzzle that you work online. I put an image in to start, but you can change it to any that you like. Good time-waster and if you check the little box for the expert level (pieces can rotate), you can waste serious time...

The Periodic Table

The periodic table of the elements is an immensely important tool for presenting information on the known elements in such a way that predictions about their properties can be made. Physical Science students should not take the time nor trouble to memorize the periodic table - the important skills are to be able to read the table and understand the patterns and trends it presents. Today's activity allowed students to draw Bohr models of atoms based on the number of protons and neutrons specified. Electrons had to be presented in their proper configuration in the electron cloud and the atomic mass calculated from the nuclear particles. Monday, we'll complete our discussion of the basic organization of the periodic table and how the concepts of ions and isotopes fit into the picture. We may not have time to cover the third section of this chapter (which is presented in the lecture packet), but that's fine. The meat of the chapter is in the first two sections, anyway.

The periodic table is like anything in science - it changes with new information. We've added new elements and the original organization by Mendeleev was based on atomic mass, not atomic number (Henry Mosely did the reorganization for that piece). However, with more and more information about elements being found, such as orbitals and quantum numbers, other variations of the basic periodic table can be found. I'm not talking about those "Periodic Table of the Vegetables" posters you see around, but rather a real reorganization of the elements that includes or is based around a different property than simply the atomic number. These alternative versions are not widely used, but they are definitely cool to look at. Here are a few examples:

This is the table designed by Professor Theodor Benfey in 1960



This one is by Mohammed Abubakr



The Najderek table emphasizes the energy levels and orbitals nicely:



The Physicists table adds in quantum numbers:



This one is just sorta weird - but pretty!

Very Mean, but Very True

Electrons

Physical Science spent the period discussing electrons and the structure of the electron cloud. The properties of the electron were described and the history of our understanding of electron cloud structure was reviewed. We'll get into the finer points of electron levels tomorrow and have time to laud the value of the valence electrons. Depending on the time required for that material, we may have time to start examining the periodic table. Our activity on Friday will allow us to relate atomic structure to periodic table organization. Make sure to have the 4.1 section review completed tomorrow so that we can go over the answers.

Physics and Honors Physics worked with Atwood's machine, which provides a mechanism for examining Newton's 2nd Law of Motion for interacting objects. Tomorrow - collisions!

Probability

Electrons are pesky - they can move and predicting the future behavior of any single electron or simultaneously assessing its position and momentum is precluded due to Heisenberg's Uncertainty Principle. But, probability can dictate where one should look if, for some reason, one had to find an electron at home. From the data Physical Science gathered, it should be clear that the first place to look is near the nucleus in the first energy level. There is a greater chance of finding an electron there than in any other location. The next most probable location is in the second energy level and the probability diminishes the further and further you get from the nucleus. So, take hydrogen: it has one lonely electron. If you had to capture that electron to sell to the circus, looking close to the nucleus would be your best bet. It would not be the best use of time and resources to set your traps beyond that first energy level.

Does that mean that the electron can't be in a 2nd or 3rd level? Not at all, and with an influx of energy that will happen. However, it is far more probable that ol' lonely will hover close to the nucleus. If you consider what we discussed with potential energy and where high and low potential energies exist for unlike charges, you might get an inkling of why this pattern occurs. For your other combination - different die, two dice thrown at once, a larger die - the first energy level should still have been the most likely in which to find an electron. However, it is completely possible that one of your experiments yielded a different result - the 2nd or 3rd being most probable. That's why this is probability, not certainty...

Honors Physics and Physics continue on with their lab unit. Most every group has completed their Newton's 2nd Law of Motion experiment with the expected result that a graph of force versus mass will yield a linear relationship with acceleration as the slope of the line. One group started today and the rest will start tomorrow the Atwood's Machine experiment - another look at Newton's 2nd Law of Motion. It pays to read over the procedure in advance, as this one requires a little bit of setup and some preliminary thought as to how to configure the masses for each trial.

Atoms

Physical Science spent time today discussing the nature of the atom. The 3 major subatomic particles were introduced (with the proton and neutron being described), as was the beginning of the development of the current model of atomic structure. Although I didn't plan it, a nice introduction of the 4 fundamental forces (gravity, electromagnetism, strong nuclear and weak nuclear) was given and generated some productive class discussion. Here are a few videos with a bit more information on that topic:

An ultra-quick overview of the 4 fundamental forces:



Now, a bit on the strong and weak nuclear forces:



And, gravity and electromagnetism:



Physics and Honors Physics continued on with their laboratory unit by completing their lab using an inclined plane to determine acceleration due to gravity and starting to use the Vernier Dynamics system to graphically and mathematically explore Newton's Second Law of Motion.

Grab the Good Luck Charms

Not that I really think the Physical Science kids will need them, but any little thing for piece of mind is fine with me. Remember those calculators, remember that you've studied all the strands of the frameworks and that you've taken pretty much all the questions from previous MCAS exams. Those unit-specific MCAS review sheets I gave you? Drew the questions from the 2004-2007 tests. Some of you have gone to the DOE site and gotten the whole exams and used them for further practice and I salute you for the initiative. Tomorrow, take your time, read the questions carefully, outline/plan your open response answers before you start writing. If you don't know the answer to a question, skip it for the moment. Another question later in the exam may provide you a clue to a memory jog that will help. Don't forget to go back to the question though! And don't leave anything blank - if you are truly and completely stuck on a question, eliminate as many choices as possible then go with your gut for the answer. We'll pick up again on Monday with atoms. I put together a simple video playlist on YouTube that you can access with the widget on the left sidebar. Click on the "Play" button to watch them in order or click the "P" to view the titles in the playlist and choose specific ones to view. They'll give you a nice overview of atoms and molecules, which we'll cover in more detail in class.

Physics and Honors Physics began working on our final lab unit that puts the Vernier Dynamics Tracks through their paces. Experiments on basic motion, acceleration, momentum, elastic and inelastic collisions and force/impulse will be conducted with the new equipment. Students are also helping to clarify the lab directions, making suggestions for procedure or equipment modifications and evaluating the quality of the results. Their effort will make next year's curriculum more efficient and, for that, I thank them.

A Day in Flux

A and B block were fairly straightforward: Physics watched an episode of Mythbusters that dealt with free-fall acceleration and lift, while Physical Science went question by question through the 2008 MCAS to analyze what skills were required to successfully choose/provide an answer. Before the end of period B, juniors were called down for the senior awards assembly and the remaining high-school population was gathered at the beginning of C block. At this point, organization sort of fell apart, as the senior awards ceremony went on for a notably long time and left both students and teachers in some state of chaos for D block. By period E, all was again quiet and Honors Physics was able to complete and test their hydraulic lift. Whew...

Physics and Honors Physics will continue with their enrichment studies this week and Physical Science will use tomorrow for last-minute MCAS review. We won't pick up again with any work until Monday, when our unit on matter and atoms will commence.

Oh, and for you outgoing seniors, please realize that college professors are actually aware of this:

Testing Skills

Physical Science tested their mental skills today with the 2008 Introductory Physics MCAS exam. Although no one was jumping up and down to share their scores, no one was weeping in their chairs, either. Between tonight and tomorrow, complete the open response questions. We will go over the multiple choice and open response questions in class tomorrow. Gather up the calculator that you want to use on the MCAS and make sure that it has fresh batteries and that you are familiar with the relevant operation keys. Review the formula sheet and make sure that you know the application of each one. Countdown to Thursday!

Physics and Honors Physics tested their hands-on skills. A and C block worked on building an electric motor. E block put together a conservation of energy apparatus. G block worked on building a working hydraulic lift model. Tomorrow, projects will continue (C block will be lost due to the senior awards presentation) with new ones being added. Fun will be had by all...