Imaginary Potential

Entries from November 2008

Circuits by Analogy

November 24, 2008 · 3 Comments

Some not so useful useful but cool sounding and true analogies I have used during my office hours while teaching undergrads about circuits:

Charging a capacitor is like falling out of an airplane.

“Charging” an inductor is like a bunch of uranium decaying.

A circuit with an inductor and a capacitor is like a pendulum.

A circuit with an inductor, capacitor, and resistor is like a pendulum in oil.

A circuit with an inductor, capacitor, resistor and AC power source is like pushing a kid on a swing.

Categories: Dave
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Physics and the Earth

November 23, 2008 · Leave a Comment

As I delve deeper into the context of the physics I’m doing at the moment, all I seem to find is more and more information about the really serious state that the oceans are in.   I’m not sure whether this is just because I automatically hear much more about it now that I work in this field, or because it’s finally getting the much-needed press and so this stuff is being found out in the public sphere more and more.

In one way, I’m lucky because at least the physics I do is contributing to knowledge of the way the earth’s systems work, and in that sense I feel that I’m at least doing something positive about this issue on a daily basis.   Bubbles are at a crucial place on the boundary of the ocean and atmosphere and better knowledge of how many there are and where they are can only improve our understanding of the exchanges between these two great reservoirs of air and water.    On the other hand, all this will have a benefit a long way in the future (it’ll probably be ten years before models that incorporate this sort of data are really being used regularly), it seems that there is less I can do on a daily basis.   I choose stuff in the shops that has travelled as short a distance as possible to get there, I limit travel by car as much as possible, I don’t buy stuff I don’t need (like silly plastic toys that are only going to get thrown away), and I try to be aware of the consequences of my choices in life as much as possible.   I truely believe that all of those are important things to do.   And many people could do more of them and I could do better – it’s all dependent on the availability of information and the availability of real options.

However, I also feel that as a scientist, there should be more I can do.   After all, I understand the issues better than most people, because it’s part of my job to do so.   I understand how science works and how the evidence leads to these conclusions.   I have spent time in the oceans, and I’ve seen some of the effects of environmental changes (and I can imagine more).   Maybe I need to have more patience, and I’ll see places to do something extra soon.   But I feel that one of the biggest motivations for really changing your life to at least stop the problems getting worse, if not to start to reverse the recent trends, is knowledge and understanding of what is happening.   Really understanding it, not just looking at a picture of an ice floe and thinking “well, that won’t be there in the Arctic in the summer in ten years time”.    People really need to understand what it is that has been done, and then very quickly get over most of the anger and sadness that this knowledge causes and move on to actual changes that can be made.   Many of them are personal and they start with better informed consumers and voters.

Some days, when physics is a hard thing to do, when there are tough deadlines and a lot of responsibility for creating my own projects and direction, and when I’m floundering in new understanding of something, I wonder why I do what I do.     And then I realise that I’m one of the few people that really has a unique role here, to communicate what is happening from direct scientific knowledge and to convince people that these changes to their outlook and lifestyles really are important, and that they do make a difference.   There needs to be a connection between the scientific facts and the individuals whose actions have caused those facts.   And that divide should be bridged by a scientist.  Maybe people don’t really think about physicists as being those who are working in this area, but there is as much physics in all this as biology and ecology and chemistry.   I think that all scientists should do what they can here.   Just understanding how science works is something that you can try to share with other people, which may help them digest the information about the environment in the news.

If you’re interested, a great place to start informing yourself about ocean-related issues is the Shifting Baselines project and also the blog below:

http://www.shiftingbaselines.org/index.php

http://scienceblogs.com/shiftingbaselines/

And number one thing (in my opinion) on the list of “things that you could change but you probably don’t really know about” is to think very hard about any fish you may eat.   Overfishing is causing tremendous damage to the ocean, not just because of the removal of fish but because of the massive habitat destruction that dredging causes.   There are some fish that are still sustainably harvested, and try to find that out.   In the UK, I’m not sure about the best sources, but the Monterrey Bay Aquarium has  a great website with recommended alternatives to some of the fish that are found in the US:

http://www.mbayaq.org/cr/cr_seafoodwatch/sfw_sushi.aspx

I think that physicists really have a role to play here…   I took a course called “Systems” in the third year of my undergraduate degree, and the much of same thinking really applies to environmental phenomena.     We may feel that because our academic work doesn’t relate directly to environmental stuff, we are not in a position to talk about it.   But sharing our understanding of science itself is really invaluable.

Categories: Helen · Uncategorized
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Instant Anger Relief

November 19, 2008 · Leave a Comment

No physics today, just the incredibly adorable and surprisingly watchable puppycam

Instant stress/anger relief.

Categories: Dave
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Compactification in String Theory Part I: Motivation

November 19, 2008 · 3 Comments

A new attempt to reinvigorate the blog!

Yes, I am aware that I already have two physics related threads that have started and ended at “Part I” (false vacua and string theory). However, I’m really motivated by the introductory explanations. I promise to come back and finish the other ones real soon. But for a while, I’d like to talk about compactification.

A word about the word…I’ve had at least two scientist friends laugh when I’ve said “compactification”. Also, the text editor I’m typing this in thinks its a misspelling. Apparently in all other science fields, the correct word for taking big things and making them small is “compaction”. 

Well, we string theorists are just a little bit cooler then you “real scientists.”  We’re not taking some obsidian and making it smaller (like my roommate, the geologist, and one of the laughers), we’re making goddamned extra dimensions smaller. You read right, the extra dimensions.

For casual, non-specialist readers (if there are any left) the first few posts will be an introduction–an attempt to explain WHY we need to “make the dimensions smaller,” what that means, and why its so hard. I hope to follow up much later with more technical issues and a few comments of my own very small research in this subject. At the very least, you will be able to read pretentious, unfunny Woody Allen short stories and chuckle with smugness.

Ok, so let’s get on with it.

(more…)

Categories: Dave
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