We've compared Ampere's law to Gauss's law, where it is a way to figure out what magnetic fields are doing for our three shapes. For those shapes the math reduces down to just figuring out the length of the path the magnetic field follows. The obvious question then becomes, what happens for everything else that is not one of the three shapes? Just like in electricity, where we had to move on to the NON-Gauss integrals, now we will need to move to the NON-Ampere situations, such as real wires that do have ends.
The general way to find magnetic fields is called the Biot-Savart rule; for us, it's just B-S.
Check out B-S for single particles that are moving. Then, check out current moving in a straight wire with ends. There is a B-S video for loops of current, as well as multiple wires and finding total B-fields. Note that current densities (uniform and NON-uniform) are used if we need to find B-fields inside wires.
To visualize B-fields for all sorts of situations, there are some wonderful 3-D simulations!
Try Ch. 28 #8 (p. 11). Use the picture and values in Ch. 28 #72, to find the overall magnetic field at a point 10 cm below the bottom section of the loop, on the line that bisects the top and bottom parts of the loop...find the three magnetic fields from the long wire and the top and bottom sections of the loop and their directions. By Friday, we'll also have an article summary (forms on front desk) of your choice.
Wednesday, February 28, 2018
Tuesday, February 27, 2018
NU Research Opportunities in Physics
A group of Northwestern professors in the Physics Department have begun a web page to help ETHS connect students (particularly juniors) for research. Check out the initial set of opportunities, and if at all interested, please see Doc V right away. There typically is space for only 1-2 students per lab, and we will consider these on a first-come basis to see if it is a good match.
Generally, consider if you will be around for just about the entire summer. This is when the work mostly gets done, and often it is a daily visit to the lab. You would be working primarily with graduate students. There will be a significant learning curve, so you would be expected to put in good amounts of time to get to a point of being productive in the lab - and ultimately you could get a piece of a project and do cutting-edge research, while in high school!
Again, just come and see Doc V as soon as you can!
Generally, consider if you will be around for just about the entire summer. This is when the work mostly gets done, and often it is a daily visit to the lab. You would be working primarily with graduate students. There will be a significant learning curve, so you would be expected to put in good amounts of time to get to a point of being productive in the lab - and ultimately you could get a piece of a project and do cutting-edge research, while in high school!
Again, just come and see Doc V as soon as you can!
Monday, February 26, 2018
Society of Women Engineers Scholarship Application
The SWE Scholarship applications are available, with an April 10, 2018, deadline. If you are female and plan on majoring in engineering or computer science, there will be 4-5 scholarships of $1000-$1500 given out. This is for the Chicagoland area.
Wednesday, February 21, 2018
Email template for Students (under 18) to Send to Political Candidates
Below is text to send to state and federal political candidates, written by students in Evanston, Illinois. The purpose is to NOT let any political candidates of any party forget about the current front page news story about violence in our schools, and more fundamentally the health and safety of our children. While the debate about gun control will continue on, it is not the only piece of this uniquely American problem. What drives some teens to want to commit mass murder?
There are four issues/questions listed, and you can demand candidates to fully disclose their positions to the voting public.
It is easy to send this to the relevant candidates in your district, state. All you need is the campaign or office email address. Use the link below to help you find contact information.
1. Just copy and paste the text into an email or letter. Edit it if you choose, we just want to make it easy for you.
2. Type in the appropriate incumbent's/candidate's name.
3. Type in your name and high school at the top. Then, type in your name at the end; include your address and email address so they know you are a constituent.
4. Send it! To find contact information for elected officials, click here. Send to members of Congress, your state rep or senator, your governor, and their challengers.
5. Share it with friends and family, regardless of where they live!! We need to do this all across the country!
If you want to share a letter for those 18 and older to send, use this template.
This is a numbers game - the more emails and letters and phone calls any candidate office receives, the more likely this issue remains fresh through the primary and general elections. It will force them to address a very difficult political issue with voters.
Copy and paste the text below:
-----------------------------------------------------------------------------------------------
Dear ___________,
There are four issues/questions listed, and you can demand candidates to fully disclose their positions to the voting public.
It is easy to send this to the relevant candidates in your district, state. All you need is the campaign or office email address. Use the link below to help you find contact information.
1. Just copy and paste the text into an email or letter. Edit it if you choose, we just want to make it easy for you.
2. Type in the appropriate incumbent's/candidate's name.
3. Type in your name and high school at the top. Then, type in your name at the end; include your address and email address so they know you are a constituent.
4. Send it! To find contact information for elected officials, click here. Send to members of Congress, your state rep or senator, your governor, and their challengers.
5. Share it with friends and family, regardless of where they live!! We need to do this all across the country!
If you want to share a letter for those 18 and older to send, use this template.
This is a numbers game - the more emails and letters and phone calls any candidate office receives, the more likely this issue remains fresh through the primary and general elections. It will force them to address a very difficult political issue with voters.
Copy and paste the text below:
-----------------------------------------------------------------------------------------------
Dear ___________,
My name is _____, and I am a high school student at _____. I’m reaching out to you today to express my horror about the school shooting in Parkland, Florida, on February 14, 2018, and to share my frustrations about the inaction of political leaders in America. With hundreds of students and adults killed and wounded since Columbine in 1999, this is not just a matter to address by tweeting your “thoughts and prayers”.
I refuse to live in a world where I am afraid to attend school; the fact that this thought has even crossed my mind is outrageous. Schools are meant to be a safe space, where students grow and learn and become strong adults. Instead, they are becoming an outlet for suffering people who our broken system has failed. How many more kids have to see their friends die? Our leaders’ inaction on this uniquely-American issue is infuriating and completely unacceptable!
When eighteen, I plan on being an active, informed voter. As a soon-to-be participant in politics, I demand that the following points be addressed by you and any other candidate running for office:
- The first issue that comes up after every one of the gun-related mass murders is whether there should be any new or modified gun laws. What is your stance on gun laws? Do you think we should have any new or modified gun laws to help decrease the number of shootings in schools and in society as a whole? If so, what are they?
- What do you think should be done to identify and help children who are struggling with mental health and/or possible violent tendencies?
- Where do you stand on funding for schools to help with student education, health and safety?
- Are there changes in the way we run schools you think should occur to improve education as a whole while reducing stress levels on our children? If so, what are they?
Sincerely,
Name and address (without an address that is in their district or state, there will be no response)Letter/email template for voters (18 and older) to send to Political Candidates
Below is text to send to state and federal political candidates. The purpose is to NOT let any of them forget about the current front page news story about violence in our schools, and more fundamentally the health and safety of our children. While the debate about gun control will continue on, it is not the only piece of this uniquely American problem. What drives some teens to want to commit mass murder?
There are four issues/questions listed, and you can demand candidates to fully disclose their positions to the voting public.
It is easy to send this to the relevant candidates in your district, state. All you need is the campaign or office email address.
1. Just copy and paste the text into an email or letter. Edit it if you choose, we just want to make it easy for you.
2. Type in the appropriate incumbent's/candidate's name.
3. Type in your name at the end. Include your address and email address so they know you are a constituent.
4. Send it! To find contact information for elected officials, click here. Send to members of Congress, your state rep or senator, your governor, and their challengers.
5. Share it with friends and family, regardless of where they live!! We need to do this all across the country!
If you want to share an email template for students under 18 to send, use this.
This is a numbers game - the more emails and letters and phone calls any candidate office receives, the more likely this issue remains fresh through the primary and general elections. It will force them to address a very difficult political issue with voters.
TAKE ACTION for our children!! Hopefully this only takes 5-10 minutes.
Copy and paste the below text:
---------------------------------------------------------------------------------
There are four issues/questions listed, and you can demand candidates to fully disclose their positions to the voting public.
It is easy to send this to the relevant candidates in your district, state. All you need is the campaign or office email address.
1. Just copy and paste the text into an email or letter. Edit it if you choose, we just want to make it easy for you.
2. Type in the appropriate incumbent's/candidate's name.
3. Type in your name at the end. Include your address and email address so they know you are a constituent.
4. Send it! To find contact information for elected officials, click here. Send to members of Congress, your state rep or senator, your governor, and their challengers.
5. Share it with friends and family, regardless of where they live!! We need to do this all across the country!
If you want to share an email template for students under 18 to send, use this.
This is a numbers game - the more emails and letters and phone calls any candidate office receives, the more likely this issue remains fresh through the primary and general elections. It will force them to address a very difficult political issue with voters.
TAKE ACTION for our children!! Hopefully this only takes 5-10 minutes.
Copy and paste the below text:
---------------------------------------------------------------------------------
Dear ___________,
I am a constituent of yours, and I am contacting you with my deep concern and, yes, anger, I feel after yet another school shooting and mass murder in Florida, on February 14, 2018, which took the lives of 17 students and staff. Since the Columbine tragedy in 1999, hundreds of students and adults have been killed and wounded in school shootings - I find it outrageous that our political leaders have effectively done nothing to address this uniquely American problem over the past two decades. The days of reciting the same canned script of “my thoughts and prayers to the families…” must end, now.
I am writing to demand that you and all candidates running for political office make your positions clear to the electorate, in writing on your website and campaign literature, on the following issues:
- The top issue that comes up after every one of the gun-related mass murders is whether there should be any new or modified gun laws. What is your stance on gun laws? Do you think we should have any new or modified gun laws to help decrease the number of shootings in schools and society as a whole? If so, what are they?
- What do you think should be done to identify and help children who are having problems with mental health and/or possible violent tendencies?
- Where do you stand on funding for schools to help with student education, health and safety? Are schools properly funded and resourced, or not?
- Are there changes in the way we run schools you think should occur to improve education as a whole while reducing stress levels on our children? If so, what are they?
This is a recurring problem that has to stop. These are our children we are talking about!
I look forward to your thoughtful response, sent to the address below. I and many other voters will be following where you and your opponent stand on these issues, how much importance you place on these issues, and what action you are prepared to take. If I do not get a response from your office, or do not find these specific questions and issues addressed on your web page, I can only assume you have no plans in mind and we would live with the status quo should you be elected. If this is the case, please do not expect my vote.
Sincerely,
Name, address, and email (your letter will not be read if you live outside the candidate’s district or state)
Tuesday, February 13, 2018
Rotational motion introduction
This is for the 3 Chem/Phys classes. In addition to gravity and the pendulum, there is the transition from linear motion to rotational motion. Rotational motion is like spinning wheels, where every point of a full object spins. This is different from circular motion, which is motion of something we can treat as a point mass moving on a circular path.
For our pendulum lab, for instance, we treat this as circular motion because we are only considering the mass at the end, and ignoring the string. Technically, if we include the string, then we would need to discuss it in terms of rotational quantities.
These rotational quantities are introduced in this video. Check it out, take notes on the new symbols and terms and relationships - the relationships are analogues to what we do for linear motion. See if any of it makes sense with a few practice problems, which can be found in the 3 Chem-Phys page of the website, in the Rotations folder. The files is called Packet - Rotations Intro. Some practice is on page 5. *Note that with rotational equations and values, we are converting into radians for angular measurements. Work together and talk things through.
Try: Ch. 9 #1, 3, 7, 9, 11 Think about the similarities to linear motion problems we have had.
*For any groups that need to collect more data for the lab, go for it. If you need to do the force sensor part, we'll wait for Wednesday when the software is available.
For our pendulum lab, for instance, we treat this as circular motion because we are only considering the mass at the end, and ignoring the string. Technically, if we include the string, then we would need to discuss it in terms of rotational quantities.
These rotational quantities are introduced in this video. Check it out, take notes on the new symbols and terms and relationships - the relationships are analogues to what we do for linear motion. See if any of it makes sense with a few practice problems, which can be found in the 3 Chem-Phys page of the website, in the Rotations folder. The files is called Packet - Rotations Intro. Some practice is on page 5. *Note that with rotational equations and values, we are converting into radians for angular measurements. Work together and talk things through.
Try: Ch. 9 #1, 3, 7, 9, 11 Think about the similarities to linear motion problems we have had.
*For any groups that need to collect more data for the lab, go for it. If you need to do the force sensor part, we'll wait for Wednesday when the software is available.
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