tidbits.Qrystal.name

In support of CJAM, University of Windsor’s campus radio station

CJAM is in trouble, and they have been asking their listeners to write to CRTC to express their support and love for CJAM. I was reminded of this today by @jodilicious, and also reminded that the deadline for expressing my concern is Monday… so I sat down and wrote the following letter immediately.

I love CJAM, and so I am writing to express my support for their application for protected status.

There aren’t enough good radio stations in the Windsor area, especially since (from my experience) CBC Radio 2 comes through so very poorly! But even where CBC Radio 2 is comparable to CJAM, it could never replace it. Student radio hosts tend to have a point of view completely different from all other radio hosts, formed both by the education they are receiving and the fact that they are younger and more aware of trends applicable to the new generations. This knowledge is evident in the music played, as well as the discussion made between songs, and also in talk radio shows.

CJAM showcases a phenomenal assortment of types of music, broadening what I would listen to normally. “Leave it to CJAM,” my friends and I say to each other when we hear something so completely unique, it could only be heard on CJAM. I love hearing music from different cultures, and even love that many of these shows are announced in the language associated with that culture. It helps me feel like a part of this great multicultural city (and world!) to be able to appreciate the cultures that make it up!

But even when the style of music isn’t unique or from another culture, it’s always interesting! Very often, CJAM showcases independent artists that don’t get played on other radio stations. Local bands know to bring their work to CJAM for a great chance at getting played. Sometimes the focus of a show is on a genre that isn’t well-known, or with an emphasis on women in music (I think this one is presented by students in Women’s Studies).

The talk radio shows on CJAM are really fascinating as well! I regularly listen to one where the hosts discuss politics in a very thought-provoking way, arguing intelligently over the ways of analysing a situation. Another show I enjoy discusses vegetarian living, and being conscious of what you eat.

I want to extend my support to other campus radio stations as well. When travelling, I always seek out the campus radio station in the Kitchener area (can’t remember what it is right now, but that’s besides the point). Why do I do this? It’s for all the same reasons I love CJAM. And if something negative happens to CJAM, it will negatively affect the future of all campus radio stations, and I really REALLY don’t want that to happen. If you know what’s good for radio, you won’t let this happen either!

So please, I implore you, on behalf of the hundreds or thousands of people who aren’t taking the time to write about their reasons for loving CJAM (and other campus radio stations), please take these words to heart. Please don’t make it difficult to find this kind of great broadcasting on the radio!

Sincerely,

Crystal McKenzie

More questions I’ve answered as a Teaching Assistant

The following questions and answers are from a course called Physics and Society, offered at the University of Windsor. I am the teaching assistant for the course, and as such I answer the students’ questions on a private online discussion board. The current unit covers the basics of electromagnetism and relativity, and I have included two of the students’ questions below that lead up to a summary that I posted for them today.

“Can you please explain field, like electric field and magnetic field”

[My response:] A field is a region of space with a measurable physical property that may vary at different points in the region.

For example, an incandescent lightbulb glowing steadily is surrounded by a field of increased temperature. This is a scalar field, because each point in space can be associated with a temperature, which has a scalar value.

For the case of an electric field, at each point it is possible to measure how much electric force would act on a charged particle, and in which direction the force would act. This is a vector field, because each point in space has an associated vector magnitude and direction.

Similarly, a magnetic field is a region of space where a magnetic force would be able to be measured, and a gravitational field is a region of space where a gravitational force would be able to be measured.

I hope that helps! If not, I will gladly explain more.

“How does the current/charge form electromagnetic fields?”

[My response:] A charge could be defined as the source of an electromagnetic field, or the electromagnetic field could be defined as that force field that surrounds a charge. They define each other, and are defined in terms of each other. They each exist because the other exists.

Since a current is just made up of moving charges, the above description covers magnetic fields due to currents as well.

It’s a tricky question, but I hope my answer helped!

TODAY, February 23, 2009, is the day before the unit test… Nobody sent in any questions before my scheduled answer session, and so I came up with the following thoughts to summarize the subjects they’re studying.

I could take the description above one step further: a charge is something that is the source of an electromagnetic field (or the other way around: an electromagnetic field is a combination of electric field vectors and magnetic field vectors surrounding the thing we call a charge).

If you are moving at the same speed as the charge (that is, you are in the same inertial frame as it) you will only detect an electric field. If you and the charge are in relative motion, you will also be able to detect the magnetic part to the field. This is why a moving charge seems to “create” a magnetic field.

If a charge is moving back and forth in a regular pattern (relative to the observer), the electromagnetic field changes in a periodic way. The changes ripple outwards in waves we call electromagnetic waves — light, radio waves, microwaves, x-rays, depending on the frequency of the oscillations.

These waves move outwards in straight lines, unless something is bending the space the waves are travelling through — something like gravity. Note that gravity is bending spacetime itself, and light just naturally follows the curve of space, and that’s why it seems to bend.

Electromagnetic waves also move extremely fast, though not infinitely fast, and the actual speed depends on the material it’s passing through (usually slower than the speed of light in empty space, which we call c).

Just remember: the “speed of light” or “bending of light” is all about the transmission of electromagnetic field information. Thinking about light as rippling changes in an electromagnetic field might be useful in trying to see why there is a constant speed of light: it is electromagnetic field information that is travelling through space, not just our everyday notion of light (which just happens to be made of electromagnetic waves).

Isn’t it amazing that we can understand this, just from understanding what happens when charges are moving?

If you enjoyed these posts, stay tuned, there will be more as the class progresses! The next unit, starting after tomorrow’s test, is about quantum theory. OooOOooooOOoo~! —Qrystal

Boldly trying to explain spacetime

There seems to be some confusion [among the students in my Physics and Society class] about spacetime, which is completely understandable because it’s difficult to visualize. I’m going to review some of the main ideas of it here, hopefully clearing up some confusion along the way.

The main quote many people gave in their summaries [of the lecture on Special Relativity] is that “space and time are no longer separate”. But what does this mean?

• It means that two observers having relative velocity near the speed of light have different perceptions of time (rate of time passing) and space (positions in space).
• Note that space, in this case, means the three directions that can be used to label a position. This is not to be confused with the idea of “outer space” or “empty space”, the emptiness between planets’ atmospheres and between nebulas and galaxies and all that.
  • The emptiness of outer space just means that there isn’t anything at any of those “empty” locations. Even if you go past these regions really quickly, they will still be empty! However, the three perpendicular directions you use to describe the positions will be different from those of someone moving at a high velocity relative to your own.
• So each observer has their own framework of space and time, which means they each can describe an event by its position (in three dimensions, say, “left-right”, “forward-backward”, and “up-down”) and the time it seemed to occur (in one dimension, which we can call “earlier-later”) according to that observer’s clock.
• Since the two observers’ clocks tick at different rates, they age at different rates, and they disagree on whether two spatially-separated events are simultaneous in time or not. In particular, measuring the length of something involves simultaneous measurements of position, and if two observers disagree on what is simultaneous, they will also disagree on the length of the thing being measured.

This does NOT mean that space and time are the same thing: each observer can always tell the difference between space and time, within each one’s own inertial frame!

• Space and time are just two separate aspects of the same thing: that mysterious-sounding “spacetime”.
• Spacetime (i.e. careful attention to both space and time) is only needed when trying to compare situations from one inertial frame to another, because the two observers disagree on some aspects of space and time.
• What makes them both aspects of the same crazy “spacetime” concept is that the way time dilates (stretches), and the way length contracts (squishes) along the direction of motion, both depend ONLY on the relative speed between the two inertial frames.

So although the idea of spacetime seems weird compared to our normal intuitive way of looking at things, keep in mind that there is a bigger framework that allows the two parts to be mixed together. The only time that this bigger framework is needed is:

• when comparing points of view that are moving at some relative velocity,
• and only if it is some significant percent of the speed of light.

Dear Twitter support:

I (and many others) have been concerned about a user by the name of @haikutwaiku who has been retweeting anything we post with the word “haiku” in it, without giving credit to the authors.

I had submitted a prior request for something to be done about the account, but that was back when I thought the main problem was that it was retweeting itself repeatedly, and I was worrying that such a thing was causing strain on [twitter’s] servers. Now it seems that haiku is becoming so popular that there is more than enough content coming in, and @haikutwaiku doesn’t resort to retweeting its own retweets anymore.

The problem has evolved, and it’s affecting more people in a more personal way. Some people simply aren’t tweeting haiku anymore:

ever since @haikutwaiku started aggregating twaiku without giving credit to the authors, i’ve been turned off posting twaiku here
— @moritherapy

while others are replying to or retweeting @haikutwaiku’s posts thinking that they belong to that account: http://search.twitter.com/search?q=@haikutwaiku

It is important to note that posts made by @haikutwaiku come from twitterfeed, which means no actual person is contributing anything original to the twitterverse (or replying to any replies to that account). I suspect that the account was set up as a service to help share the haiku, but without attribution, this is plagiarism! This really isn’t fair to those of us who take so much care in crafting beautiful works of poetry.

Here is a twitter search containing excerpts from conversations about @haikutwaiku, highlighting terms such as plagiarism, steal/stole, bot, attribution, and credit: http://search.twitter.com/search?q=plagiarism+OR+steal+OR+stole+OR+bot+OR+credit+OR+attribution+@haikutwaiku

Although it pains me to think that @haikutwaiku’s 700+ followers will miss the constant feed of haiku, the lack of attribution violates twitter’s terms of service…

… unauthorized “re-tweets” (poaching and posting other users’ updates) passed off as original content* (Does the asterisk mean there was something more to this rule? There is no clarification on the page!)…

…and it also offends many people whose words are being redistributed without attribution.

Thanks in advance for whatever you can do about this situation!

I will post updates to this post as they come in.

UPDATE: they acknowledged the request for support, but have deemed it solved after saying that they will “keep an eye on the account”. Maybe that’s just a way for them to stop the support ticket from re-prompting us to comment… or maybe that’s a way to sweep the notion under the rug. Maybe they’re just waiting for more people to complain. PLEASE ADD YOUR SUPPORT TO THIS SUPPORT! I implore you! and thank you.