Search This Blog

Friday, September 30, 2016

Possibilities for research in an NU lab - some quantum implications!

Especially juniors, let Doc V know if you have any interest in the lab of Prof. Chandrasekhar. There are some research options that will be available!!

Thursday, September 29, 2016

For Classes

Hi everyone, my apologies for having to get home to get a sick kid to the doctor.

Periods 1-2, 8-9:

The quizzam is tomorrow, so you have a chance to do review sets. One is on the school website. Go to the Newton's laws folder, and check out the Review Set. Solutions and explanations are all in the file. There is also a good site with practice questions at Learn AP Physics C.  Click on Newton's laws for practice questions and solutions.

If you need to do any last minute finishing touches on the lab report, you can do that. Share labs with Work together to make sure you are good with the HW sets, which are all collected tomorrow.

Period 3:

Watch the launch scenes from the movie 'Apollo 13.' Use the video guide the substitute gives you as you watch, and think of things in terms of Newton's laws that we are studying. Think about what forces are involved, what the astronauts would be feeling at different stages of launch, and the resulting motion of the rocket.

Monday, September 26, 2016

Full-tuition scholarship opportunity for women in STEM

Senior ladies, if you are going to study anything in STEM in college, you may want to check out the Science Ambassador Scholarship program, where one woman will win a full-tuition scholarship to college! The first step is produce a 3-minute video lecture on any science topic you are passionate about, and submit it. Check it out!

Thursday, September 22, 2016

Responses to Science Issues by Presidential Candidates

If you are interested in the responses to 20 science related issues from Hillary Clinton, Donald Trump, and Jill Stein, check out this Scientific American article. Gary Johnson did not respond.

Sunday, September 18, 2016

Classes for Monday - Wednesday, Sept. 19-21

While I am in NYC, the substitute has detailed work for each day. Some of this will require watching a video or two. Take notes on these, and keep track of any questions, so we can re-group on Thursday.

Period 3:
On Monday, check out two videos. One is on Newton's 2nd law of motion (F = ma). The second video is on Newton's 3rd law of motion (action-reaction). You should be remembering these laws by number. Take notes on these, and we will be using them quite a bit throughout the year - since forces are around us all the time, our entire lives, these basic laws will help us understand a whole bunch of things!!

Note that Wednesday is a C-day, and juniors (most of teh class) will be in assigned rooks for PSAT stuff.

Periods 1-2 and 8-9:
On Tuesday, watch and take notes on a video for finding acceleration and tension in systems of objects.

On Wednesday, watch and take notes on two videos for integration (anti-derivatives) and circular motion examples (centripetal force, mv^2/R).

Thanks, and we will be making sense of these when I am back Thursday!!  :-)

Wednesday, September 14, 2016

Gauss's law for conductors and NON-conductors

In 4 Chem-Phys we are trying to understand the differences between conducting objects that have a net charge and NON-conducting objects that have a net charge. Remember, what we are discussing is only for STATIC electricity.

Conductors/metals have those metallic bonds, where the delocalized electrons can move. If an E-field interacts with a conducting material, such as one of the shells we were talking about in class, then that shell can polarize. The consequence of the polarization and the behavior of conductors with static charge is that the net charge ends up on the outer surface. This also means that the E-field inside the conducting material is E = 0. Note that if the E-field is not 0 inside a conductor, then there would be an electric current, and not static electricity. The video for conductors is here.

NON-conductors/insulators do not have metallic bonds or a 'sea of free electrons,' which is why they do not conduct currents. But this means it is OK for any net charge to be spread throughout the volume of the material - it can't move, so it would still be static charge. According to Gauss's law, there will be an E-field inside the material. This is where we need to work with charge density, which is charge/volume. Our job using Gauss's law is the same as always: try to figure out what to put in for the charge inside any particular region of the system. The video for NON-conductors is here.

Saturday, September 3, 2016

"Zombie Genes" that turn on after death

Thank you to Chirasree for finding this article:

Check out an article about "zombie genes," which have been discovered in various animals that have expired. These are genes that do not activate or do much of anything when the organism is alive, but instead become active after the organism dies. This may have important implications for something like organ transplants. Who would have thunk it?!

Thursday, September 1, 2016

Good example of how STEM works in this day and age - Collaborations for Power Grid Security

My alma mater, UIUC, just had some $18 million dollars in grants given to it (the College of Engineering, that is) to develop the most robust platform for testing the security of the U.S. power grid. The U.S. is in the process of a long-term renovation of the decades-old power grid, which is outdated in terms of both technology and security, and developing the whole 'smart-grid' concept. This is one where engineers and power companies will have better data and faster responses to problems with the grid, where computers can automatically control where and how much power is being sent to different users on the grid based on demand and resources, better efficiency and cost control, better energy conservation, hooking up new energy sources to the grid (such as solar, wind, geothermal, bio-based sources, etc.), and increasing infrastructure to places where it does not presently exist so there can be expansions of wind farms and solar farms in the future. This is a HUGE project and will proceed for many years to come (making it a good time to be a civil, computer, environmental, or electrical engineer), but without a robust security system on the grid, it will always be vulnerable to attacks, especially via the Internet. This type of research is absolutely crucial for the U.S. future.

Plans for September 1

I am really sorry for being out, but a fever and stomach issues are forcing me to go back home. Please do the following for today:

Periods 1-2, 8-9
The quizzam is still on for tomorrow, so today be sure to get into study groups and be sure the various homework sets are making sense. Homework sets are collected tomorrow. Be sure the lab is shared with me at You can try the practice problems the substitute teacher will pass out, and these and solutions are on my school site: go to the 3 Chem-Phys site and in the Foundations folder is the file called Review Set. Other resources include reviewing sections in the textbook, trying other odd problems and checking answers in the back, and trying and checking yourself with the worked examples in every section. We are doing stuff from chapters 1 and 2 primarily.

Quizzam main topics: 
Vector addition, subtraction                 Vector multiplication
Derivatives of functions (no algebra required!), y = cxn
1-D motion problems with constant acceleration and non-constant acceleration
2-D motion: relative motion, projectiles
Motion graphs        Graphing data           Standard deviation, error bars

Period 3
We will hold off on your rankings of issues until tomorrow. Today, I want you to try getting data for our speed lab. You will get the lab sheet and some additional direction from the substitute teacher. The measurements you will need to make are for a marble rolling down a ramp and onto the table-top. You will need to select 5 different distances from the end of the ramp, and then for each distance do 4 time trials; you will be using the average time for each distance you select. Be sure to start the marble at the same height on the ramp every time you let it go, because you want to have the same speed on the table every single time. Keep track of all this with a data table you and your partners decide on. Ultimately we will be making a graph to determine the speed of the marble. Remember that speed = (distance)/(time), or v = d/t. We will get into the analysis tomorrow.

Thank you everyone, and let's make the most of it until tomorrow. Happy Thursday!    :-)