Monday, March 29, 2010

Spring installing.

As you've probably noticed, I made some changes to the template for my blog today. Blogger just came out with some new templates with more customization options. I'm quite pleased with the new look, especially the way the header turned out.

I spent most of the rest of the day trying to install various programs on my Ubuntu desktop, and learning Sage. Installing on Linux systems comes in a wide array of difficulties from 'one-click simple' to 'mind-bogglingly complex'. It took me several hours to install two programs, and required me to learn and use several new commands.

But, there is a definite sense of accomplishment that comes with having figured out something that complicated which you don't get when installing a program on Windows.

I've actually accomplished quite a few things on my list (and off it) over the last few days, and I'm feeling pretty good about it, although I can hardly believe spring break is almost over. I really need at least another week to get everything done that I wanted to get done.

Friday, March 26, 2010

Homework & haircuts.

Just a short post to keep you up to date on my doings:

After nearly a full day spent doing things on the computer yesterday, I forced myself to take a break today and work on some of the homework I have due next week. I can't believe how rapidly I forget things when I'm not actively using them, ugh. I managed to get on the schedule for the Vis tonight, so I'll be up there imaging if the weather is good. I also rather stupidly decided to give myself a haircut this morning. I say stupidly not because it came out badly, but because now my head will be that much correspondingly colder up on Mauna Kea. In fact it's better than I had hoped for, although it's still a stop-gap measure till I can get a real haircut.
I don't have hair scissors, so I used my electric shaver, and since I can't see the back of my head and the only mirrors in the house are attached to things, I used my camera to take pictures of the back of my head to make sure I got it straight. Ingenuity triumphs once again! (or was that necessity is the mother of invention?)

Thursday, March 25, 2010

Shadow and flame.

Today I installed Ubuntu on my computer as a dual boot. Ubuntu is a particular flavor of Linux, currently one of the most popular (and also the most user-friendly, or so I've heard).

While part of me is exulting that I have taken a step towards being able to call myself a true computer geek, another part of me is a bit shamefaced because I didn't do a traditional dual-boot routine, where you partition your hard drive, back everything up, and hope nothing goes wrong while the second operating system installs. I used a hitherto-unknown-to-me program called Wubi which makes installing Ubuntu as simple as installing any other program on Windows. You simply download it, run it, follow the prompts, and it sets itself up. You can even uninstall it directly from within Windows, if you decide you don't like. It sounded so easy, in fact, that I was more than a little incredulous when I first heard about it, but after reading reviews from a couple of tech sites I decided to go ahead and try it out.

There were several reasons I decided to install a Linux operating system on my computer. Actually...now that I think about it, they're all pretty much the same reason: certain programs run on Linux, and not Windows. One of those programs is IRAF, and though I already have Fedora (which is another version of Linux) installed as a Virtual Machine in Windows 7, it is way harder to install IRAF on Fedora than it is on Ubuntu. However, it was overshadowed by another program, Sage, that was the main motivation behind my decision. 

Sage didn't make it onto my to-do list a few days ago because I wasn't aware of what it was then, merely its name. Since then, however, it has become of great importance to me to get it installed. Sage is sort of like...how to describe it? It's "a viable free open source alternative to Magma, Maple, Mathematica and Matlab", according to the website. The mentioned programs are all what are known as Computer Algebra Systems, or CAS's. A CAS is your best friend when trying to do most kinds of higher math, because they can do all kinds of amazing mathematical maneuvers. The most amazing part (as reflected in their names) is that they can actually do algebra, a highly symbolic undertaking.

Anyway, these programs are used by researchers all over the world, but they all have something in common: they ain't cheap. Not by most standards, and certainly not by the standards of a poor college student. So you can see why I was so excited to find a free one ("free" as in no cost, and, since it's open source, "free" as in freedom). Also, their use is allowed, and even encouraged, by one of my professors for the homework and tests he assigns (which gives you an inkling of the difficulty level of said homework and tests...).

The really cool thing about Sage is that it's not just one program, it's a collection of a whole bunch of open source and free mathematics programs from all over, all tied together with the computer language Python, a language that I have some limited experience with (so this does fall on my to-do list, in a round-a-bout way!). In fact, when I finally got Sage up and running this evening, I was able to go ahead and write a 'for' loop on my own before getting to that part in the manual, because it uses basic Python for the interface.

So far, Ubuntu has been pretty good. It's definitely a little different from Windows, but not too bad -- I can see why some people would prefer it. Who knows, I may even come to do so myself some day. At the same time, using it today, I felt a strange sense of discombobulation from seeing my now-familiar computer with a different look and feel. It was almost like being away from home, in strange territory. But I think that will pass in time. I'm writing this post in Ubuntu right now, as a matter of fact.

Some of you might be wondering what I like most about Ubuntu so far. Is it the fact that it, like Sage, is open source and free, a common operating system for people who enjoy freedom? That it is stable and new-user friendly? That almost any program that runs on Windows runs on Linux, plus many that don't?


No...(though those are all valid reasons, to be sure)


It's the fact that I found an app that lets you paint fire on the screen with your mouse!

Yes, I just wrote my name in fire. On my desktop.

Yes...those of you who know what a pyromaniac I am will understand. I could hardly stop playing it with for the first few hours after I discovered it. With the touch of a button and a flick of the wrist, you can send surprisingly realistic simulated fire searing across the desktop, then dispel it just as easily. Underlying programs are not affected and go about their business, so if you feel like it, you could write a document while your screen is ringed in flame (and yes, I have tried that).

Anway...it's getting late, and I need to catch up on my sleep from a late night last night. I didn't get around to installing IRAF on Ubuntu today, so that will be a project for tomorrow. A hui hou!

Tuesday, March 23, 2010

Take two protons and set them 1 femtometer apart...

If you took two protons, stuck them together at the typical distance of an atomic nucleus, and there were no strong nuclear force holding them together, how fast would them be moving when they were a meter apart? That was the question I woke up pondering at 6 AM this morning. Being a bit groggy, and still half asleep, I tried using Coulomb's Law and Newton's Second Law with an integration, until I came to my senses and realized that the protons were not only moving relative to each other, but might possibly be moving relativistically, which would make the integration a whole lot more complicated. I did what I usually do when faced with a tough integration: look for an alternative way. Then, in a flash of inspiration, like the sun breaking through clouds, I found one: the Conservation of Energy! With that solved, I was able to go back to sleep (a good thing too, I need to catch up a bit over spring break).

Now, in the clear light of day, I decided to find out the answer, and I thought I'd share it with you, too.

Start with two protons 1 femtometer apart (1 femtometer = 1 quadrillionth of a meter [\(10^{-15}\)]). That's roughly the scale of an atomic nucleus. Using Coulomb's Law to find the force between the two protons, it turns out to be a whopping 230 Newtons! That's almost 52 pounds of force each single proton is feeling from the other! Which is absolutely incredible when you think about it...
Continuing on, the potential energy of each proton for this configuration turns out to be \(2.31\times10^{-13}\)  Joules. At a distance of 1 meter from each other, essentially all of their potential energy (>99.99.....%) will have been turned into kinetic energy, so using the Conservation of Energy and performing the calculations, I find that the protons are disappointingly classical, moving at a mere 8.1% of light-speed, or a little more than 24 thousand kilometers per second, or approximately 146 million miles per hour. At that speed their relativistic mass increase is a negligible 1.0067. Problem solved.

Still interested in the incredible force each proton feels, I calculated the acceleration they would be subject to at the instant of release and got an absolutely mind-blowing \(1.38\times10^{29}\) meters per second squared. That's... 10 billion billion billion times more than the acceleration we experience here on the earth's surface (10 billion billion billion g's, if you like).

The moral of the story? Be thankful for the Strong Nuclear Force today; its residual effects left over from holding quarks together inside of protons and neutrons hold those same protons and neutrons together in the nucleus.

Monday, March 22, 2010

To-do

Things to do over spring break:
  • Install and start learning IRAF.
  • Check out and start learning \(\LaTeX\). In progress.
  • Brush up my (minimal) Python coding skills.
  • Check out Maxima. Did, found it to be part of Sage.
    • Download and begin learning Sage. In progress.
  • Check out GeoGebra.
  • Start learning Synfig. Started...
  • Figure out new Blender interface.
  • Figure out how to integrate LuxRender with Blender (possibly).
  • Learn how to use Avidemux (possibly).
  • Explore JavaScript a bit more (possibly). 
  • Do Partial Differential Equations homework. Started. Got stuck.
  • Do Electromagnetism homework.
  • Finish up Gravitation and Cosmology homework. 
  • Brush up on Calculus homework (possibly). 
  • Finish Complex Analysis homework. Done!
  • Fill out census form. Done!
  • Do taxes. Done!
  • Clean my room. Done!
  • Figure out class schedule for next semester. 
  • Update this blog a little more frequently. Pretty well.
  • Finish moving all my music onto my new computer. Mostly done. 
  • Check out possible scholarship/internship opportunities.
  • Get up to the Vis at least once. Did!
  • Go to the beach (if it warms up and stops raining).
  • Do various other, as-yet-undetermined, things. 
  • Enjoy life in Hawai`i, even if it is rainy and cold currently.
Oh, and sleep and eat should probably be on there somewhere as well.

Sunday, March 21, 2010

Trying to build a working cloud chamber, first try.

As promised, here is a report of the rest of my day yesterday. After classes were done, I got together with two of my classmates to try to build a working cloud chamber for our project for Modern Physics.
If you're interested in how to do it, here's the setup we used: We took a Styrofoam cooler and cut off the bottom so that it would fit nested inside the top. We then filled the bottom with dry ice, and stuck a customized aluminum baseplate with a rim on top of that (aluminum makes the awfullest noise when placed in direct contact with dry ice as it cools to the −109.3 °F temperature of the ice. Sort of a screechy metallic shriek). On top of the aluminum, we placed our radiation source, an americium pellet from a cannibalized smoke detector. [Side note: I just did a little research on americium, and wow, I knew americium was highly radioactive, but I didn't know it was 3.5 times as active as radium. Or that it emitted gamma rays. I thought it was mostly relatively benign alpha particles (helium nuclei). I will keep that in mind when we run the experiment again...]
Anyway, after that, we placed a plastic container to be the actual cloud chamber upside-down on top of the aluminum plate. The container had strips of felt that had been wetted with 99% pure isopropl alcohol stuck to its bottom, which became the top of the chamber when it was inverted. On top of that, we placed a hot water bottle.
Since a picture is worth a thousand words, here you go:

 In this picture you can see our setup: Styrofoam cooler, aluminum plate (with handles), plastic container, hot water bottle, and americium pellet in the very middle (actually, it wasn't a pure americium pellet, it's really an aluminum casing with only a tiny spot of americium showing). The light was there for illumination.

I should probably explain the principle behind a cloud chamber, for those of you who aren't familiar with it. In theory, the hot water bottle pressed against the felt-soaked isopropl alcohol would cause it to evaporate, whereupon it would cool and sink towards the bottom of the chamber. At the bottom, it would be much cooler because of the dry ice just beneath the chamber floor. The alcohol would enter a supersaturated state, forming a cloud such that the slightest nudge from equilibrium would trigger condensation into tiny droplets. The alpha particles emitted by the americium, which are really just doubly-ionized helium nuclei, would provide such a trigger, allowing us to watch where individual atomic nuclei are going. Which is pretty amazing when you stop to think about it.

Now, after having told you all this, I hate to break it to you that our experiment didn't work because we were unable to initiate the formation of a cloud. We have several theories, which I won't bore you with, as to why it didn't work, but the upshot is that we just don't know. Apart from that, we discovered a few other hurdles with our setup, all of which simply gives us more to tweak and tinker with as we try to get it going. When we do, rest assured you shall have pictures.

On the lighthearted side, we had a little dry ice left over after the experiment, so to amuse myself I had fun dropping little bits into any standing water I could find around the house. Doing so made me thirsty, so I indulged in some of the official drink of mad scientists everywhere:

  (Pellets of dry ice in blue Mountain Dew makes a most refreshing cold beverage)

Saturday, March 20, 2010

The Residue Theorem

Today was, all in all, a rather interesting day.

To understand why, I need to back up to Thursday night, when I was finishing up my homework for Complex Analysis. Of the ten problems assigned, nine of them took my twenty minutes or less to complete (because we'd gone over how to work them in class already). The last one was a stumper. In principle, it was a piece of cake after the problems I'd been doing: simply perform an integration over a square region over four different complex functions. Yet over the next three hours I attacked that problem with every trick, technique, or theorem I know of in both the real and complex plane, to no avail. I finally gave up frustrated at 10 o`clock, because I had been up late for the last few nights and really couldn't stay awake any longer, with the intention of working on it in the morning before class.

Before retiring for the night, though, I hit upon a method to compute the integral, in principle, assuming several conditions were met. So this morning I began chipping away at the problem again. After removing all the difficulties to my satisfaction, I proceeding to the tedious (for me) work of actually writing out the problem, made all the more tedious because I anticipated several pages of computations.

And that's when it hit me: after doing a bit of preliminary setup, the closed nature of the path of integration meant that most of the results canceled in pairs, leaving only a simple complex integral, which I did in about half a minute. You can hardly imagine my elation when I realized that I was only dealing with a page or two of writing for all four integrals, instead of the the two pages each I had been envisioning.

Even with the reduced amount of writing, I still wasn't able to finish it before class, but the first thing Dr. Figueroa did was to announce that the homework was postponed until after Spring Break, because he hadn't been able to work out that very same problem with the material we've covered so far, despite staying up till one in the morning working on it (we're using a free textbook from off the Internet, which doesn't come with solutions). He mentioned that the problem could be solved using techniques later on in the book, using something called 'the method of residues' which caught my ear because it sounded like an apt description of what I had found: most of the problem disappeared, leaving only a 'residue', a single, simple, complex integral. When I mentioned I had figured out how to solve the problem, he was intrigued, and had me demonstrate it at the white-board. When he figured out where I was going, he got quite excited, jumped up from his chair, and immediately proceeded to put it all on a firm theoretical footing, then discovered a way to reduce it from the clumsy sum of four parameterizations I had been using to an elegant single parameterization over a circle, which reduced the problem down to a few lines. I think I made his day; he was still pleased as punch when class ended.

I did a little digging, and apparently what I discovered (arithmetic errors aside; I didn't have time to fully develop it) is know as the Residue Theorem, and is a standard and well-known tool in complex analysis.

The other interesting part of my day was the part where I and two classmates attempted to build a working cloud chamber for our project for my Modern Physics class and the fun I had with some of the leftover dry ice, but it's getting late, and that actually has some pictures to go with it, so I will save it for tomorrow when I can really do it justice.

Wednesday, March 17, 2010

The Texture of the Atmosphere

The second candidate physicist for the position of Assistant Professor gave a talk at school today. He's an atmospheric physicist, a category of people I've never really run into before. His talk was quite interesting, all about weather phenomena at scales not usually considered, interspersed with talk about his work on finding low-cost ways to capture lots of weather data using methods that haven't been used before (he currently works at the University of Nebraska at Kearney, I might add). It covered a lot of scales of the atmosphere that we don't usually think about, mainly less than a day in time and less than a kilometer or so in distance. For instance, one experiment he did was to cover the top of a building on the UN Kearney campus with a 5x6 grid of buckets to record how much rain it received, and how fast. The data showed that just over the scale of the building, some buckets received more rain than others (there was also something about how it showed when the rainstorm changed from one type to another during the middle, but I couldn't quite follow that part). Although he has done a lot of different weather related work, rain is his current focus, and he even got some small NASA grants to study it (gosh, you think he might enjoy Hilo?). As one professor quipped while he was going over the details of a particular sophisticated rain gauge, "Here the problem is not whether you'll get the rain, it's that it will most like swamp your detectors!"

Now that I've seen both candidates for the position, I don't envy the search committee their decision, as they both seemed like good, qualified individuals with nothing really to pick one over the other. Whoever they pick, it'll be interesting to watch, especially if they begin teaching next semester (certainly a possibility).

Monday, March 15, 2010

Messier Marathon debriefing.

Well, the Messier Marathon last night was a bit of a downer. There were some really high clouds in the early evening that slowly dissipated over the first hour and a half of night, blocking people from seeing the early objects. For those of you who don't know what the Messier Marathon is, let me back up.

Charles Messier (MESS-i-ay) was a French amateur astronomer who lived from 1730 to 1817. His major abiding love in life was comets, and over his lifetime he found or helped find 13 of them, not bad for someone using a 4-inch telescope. One thing that really bothered Messier was that there are a lot of things in the sky that look like comets [read: fuzzy blobs] (mainly 'cause with the resolution he had, pretty much anything that's not a star or a planet would look like a comet). He made notes of the location of these counterfeit-comets, and eventually decided to publish his list of them to help other comet hunters avoid being fooled by them. He published several versions, with a list that grew to 103 before his death with an additional 7 added later that were deduced from his notes.

Fast forward to the present.

No one remembers any of the comets Messier found, but his list of objects, the Messier Catalogue, is a fixture at every star party there is. That's because the objects he found, due to the fact that he was using a small telescope, are among the brightest and easiest to see in the sky. Each object on the list has its own M-number, for instance, the Andromeda Galaxy is M31, the Pleiadies are M45, and the Great Nebula in Orion is M42. Anyway, since Messier was observing from Paris, all the objects in the list can be observed from the northern hemisphere. It also works out that, due to the way they are distributed on the sky, there are some nights in spring around this time of year when you can see all 110 objects in one night, if you start when the sun sets and keep going till dawn. That's a Messier Marathon, which was going on last night, though as I mentioned, the early evening clouds prevented people from catching the objects close to the sun.
Thankfully, the clouds did dissipate over time (although I don't think they ever went away completely), so it wasn't a total failure. The sunset did produce some really dramatic colors in the clouds, though, as you can see in the picture below:


So it was a rather interesting night, despite the observational difficulties.

One other random thought: I was looking up Hawaiian words in the dictionary, and came across this lovely phrase:
 Lau ā lau nā hōkū o ka lani
"hundreds and hundreds of stars in the heaven".
(According to the dictionary lau typically means something like "many", but it also serves as "hundreds" in this context)
It's interesting to me that Hawaiian often has a sentence order remarkably similar to English. I hope to be taking Hawaiian 101 next semester, so I can investigate it more fully.

Sunday, March 14, 2010

Insanity, n: Doing the same thing and expecting a different result.

You've probably heard that before. But what do you call it when you do the same thing and actually get a different result? I've always wondered about that. Especially when it happens to me. Take today, for instance.

As some of you may know, I'm working with one of my professors, Dr. Takamiya, on a research project she's doing right now about star formation rates in galaxies. We've been trying to install a flavor of Linux called Fedora on a Virtual Machine on my computer with no luck for the last two weeks (a Virtual Box simply means that you can run one operating system within another one. I'm still running Windows 7, but I can open up a window and run Fedora 12 in it). We're doing this because IRAF (Image Reduction and Analysis Facility), the premier astronomy data reduction package, doesn't run on Windows.  We maneuvered our way around several obstacles such as enabling hardware acceleration on my processor by flashing the BIOS and figuring out which of the many versions of Fedora was the correct one to download and install, until we got to the part where the instructions couldn't be simpler: "double-click the 'Install to Desktop' button and follow the prompts". Only double-clicking the button had no effect. After two hours spent double-clicking the button and searching for solutions to the problem on Tuesday, we were ready to look into alternate ways of installing it that would be a bit more involved.

I was pursuing one of those ways this morning, when I idly opened up the virtual machine hosting Fedora and double-clicked the button. And what should happen, but lo and behold, it worked! The only difference between this time and last time I tried to install it is that this time my computer was physically in a different location, sitting on my desk instead of in Dr. Takamiya's office. I have no clue why it worked this time, but the important thing is that it does (setting a bad precedent for future sanity) meaning I can start moving forward again from where we've been stuck these last two weeks. So all's well that ends well, I guess.

Saturday, March 13, 2010

How many Ph.D's does it take...

UH Hilo is planning to hire a new physicist to fill the vacant post of Assistant Professor, vacant after the Chair of Physics and Astronomy retired last semester. They narrowed it down to two people, and are bringing them to campus for evaluation. So today I got to sit in on the colloquium given by the first one, an experimental high-energy particle physicist. The talk was pretty routine as talks go, all about searching for cosmic strings in GOODS and COSMOS data, with the unsurprising result that they haven't found any. But there was a humorous episode about halfway through when the laptop the presenter was using to present started hibernating. Apparently he had his presentation on a USB flash drive, because he was able to get it up and running on another computer pretty quickly, but it led to the amusing sight of first one, then two, then three, and finally four of our physics and astronomy professors, including the new Chair coming up to offer assistance and see if they could get it going again (hence the title of this post). I can hardly wait for Tuesday when the second one will be giving his talk (he's an atmospheric physicist, so it will be a bit different).

In other news, I am doing well, though quite busy recently. I've been trying to organize the monthly UAC trip up to the Mauna Kea Visitor's Center, something I haven't done before and which I'm learning about the hard way. I still don't know if I have everything down, but I guess I'll find out tomorrow when I go up.

Tuesday, March 9, 2010

In which I try my hand at poetry

Today: A Haiku
by Daniel Berke

Strong wind and cold rain
Not a good day for walking
But I have no choice

In other news, someone yesterday at church told me I reminded them of the Dread Pirate Roberts from The Princess Bride in look and speech, which caught me completely by surprise. Now if only I had that fencing skill...

Sunday, March 7, 2010

Various Errata

Hello everyone,

It's been a little while since I wrote, due to being busy with school, but that is finally starting to slow down a little after the hectic last two weeks. "Slow" is a relative term, of course, but I actually have a bit more free time today that I haven't really had for the last few days. Hence this post.

I wanted to mention two things today: the first is a music group I came across a few days ago, and felt I had to mention. It's called Beethoven's Wig, and if you like classical music, you are almost guaranteed to like this site. Even if you don't like classical music, you might like this site. Beethoven's Wig is the brainchild of a guy named Richard Perlmutter, who takes famous (and not-so-famous) classical works and sets words to them, with a lyrical skill I have seldom seen. The words seem to flow so naturally to the music that it makes you think the original composer simply forgot to include them, but they manage to be both funny and (usually) informative too. They often include information about the piece, the composer, or other information, and are probably going to be stuck in your head for quite a while after listening.  Go to the "Music" link where you can listen to full versions of all the songs on their 4 CD's. Enjoy!

Second: I finally got around to taking some pictures of my new computer, alongside my old one. Behold!
(The new one is on the left, if you don't know)

(View comparing the width of the two computers. Note the full keypad on my new one)
Both computers in the wild. I needed to use them both for the Partial Differential Equations take-home test you see me working on there in the picture.

I wasn't able to capture it on my camera, but I wanted to mention the beautiful color scheme on my computer. I got such an incredible deal on the rest of my computer that I splurged and spent a little extra to get the white color scheme instead of the black, and I'm glad I did. Normally I'm a strict member of the "form follows function" school of thought, but I just couldn't stand the default black color scheme that it came with, and I don't regret it. It's actually not just plain white, it's got a sort of inlaid gray pattern that looks like a river, or a blizzard, or something. It's very pretty, too bad I couldn't capture it.

Thursday, March 4, 2010

My-ren

I've been too busy to write recently, but I wanted to relate an interesting experience I had today while walking to school. I heard a siren start up somewhere in front of me and to my right -- I couldn't see it, of course, but I could tell by the Doppler shift that it was getting closer. In my subconscious, I also noted what sounded like an echo of the siren coming from behind me and to my left. I didn't pay much attention, because it wasn't very loud, until the siren cut off but the echo kept going. At this point, I suddenly realized that it didn't sound quite like an echo...and come to think of it, it sounded like it was coming from on top of a nearby telephone pole! But it too stopped after a second or two, and I still wasn't paying much attention... until the siren started up again, and with it the strange noise, and everything suddenly clicked and I realized what it was: it was a myna imitating a siren!

The realization caused me to do a double take, because that bird was really good! It was keeping almost perfect time and pitch with the ambulance, which crossed the street in front of me a few seconds later. I'm still not sure what to think. What do you call a myna imitating a siren? A my-ren?

Monday, March 1, 2010

Tsunami aftermath.

Just in case you are wondering about the extent of the damage from the tsunami here in Hilo...
 "In Hawaii, water began pulling away from shore off Hilo Bay on the Big Island just before noon, exposing reefs and sending dark streaks of muddy, sandy water offshore. Waves later washed over Coconut Island, a small park off Hilo's coast.
The tsunami caused a series of surges that were about 20 minutes apart, and the waves arrived later and smaller than originally predicted. The highest wave at Hilo measured 5.5 feet high, while Maui saw some as high as 6.5 feet."
Translation from news-speak: it was pretty much a fizzle. Coconut Island is basically flat, and at its highest only gets maybe 4-5 feet above sea level. It's the island just behind me with the trees on it in this picture (taken in August, not right before the tsunami!):



Still, better safe than sorry, after all.

Also,
"Sirens blared in Hawaii to alert residents to the potential waves."  
I can attest to that one!