Sales pitch

I gathered a new appreciation for quality salesmanship today. A guy nearly bullied me into buying a totally pointless water filtration system. You know the kind that home owners are supposed to get because tap water is apparently killing people left, right and center?

He came to my door, which I answered foolishly thinking that it could be the real estate. He then said that he heard that I had some complaints about our water, which I did. One evening recently a neighboring construction site apparently dumped a bit of clay or something into the water - which cleared up promptly and caused no problems. That is my hypothesis at least. Anyway, he must have heard this story from the neighbor. He asked if I knew what happened. Of course I said no, although I had a few hypotheses, none of which involved millions of people suffering from low quality tap water in Australia. At this point I held out hope that maybe he was a city council worker door knocking to explain the situation with the construction. But then the catalog came out. Urghh.

"I'll tell you why" he said. He told me all about the deadly chemicals in my water - chlorine, arsenic, chloroform, something mumbled that sounded hideously dangerous, and *gasp* even bacteria. Bacteria! In my water! Good heavens no! I'm surprised that he didn't mention fluorine. He proceeded to tell me all about what their filters do. It turns out that it doesn't just purify water, it adds trace minerals to make you healthier. You mean, just like tap water? I didn't say that although I wanted to. His barrage was just so fast that I was left there: standing at the door completely dumbfounded. I must have looked like the usual sucker because he kept going on with this shtick for several minutes with me just standing there wide eyed. Truth is, he was selling such blatant rubbish I couldn't believe my own eyes! For only $27 something or other a month (for the first month, and then $40 after that) he would sell me a filter that:

1. Either does nothing at all, or
2. Modifies the tap water in a way that is completely untested, undocumented and unregulated

I'll stick with tap water thanks. Worse yet, to even qualify for the filter you must:

1. show three points of ID, and
   
2. show that you have been living at the premises for at least a month, and
3. you have to sign some piece of paper on the spot before they make you
   
4. put in an application to get the filter, presumably so they can check your credit rating.
5. Only then can you get it installed.

Can you take away the brochure and study for yourself? Nope, they take that with them. Contact details? Just a phone number. Any journal references? Fat chance. Company name? Didn't even get that bit of info.

Finally, with a not at all subtle look of "do you really want to hurt your family" on his face he asked why I wasn't interested in the offer. I wanted to say "because I'm a physics major and I know how to do some research," or even just "I have some common sense," or "I don't think that the government, for all its faults, is in the business of making the voters and tax payers sick." But I didn't say any of those things. I was too dumbfounded. I just said "I'm not interested."


Oh yeah, and his best line was: "[with our water filter] You'll feel 80% better, because the human body is 80% water."

Well, I've been avoiding this

for 133 days apparently. The simple reason is that

1. I stopped from posting temporarily, for a very good reason, and
2. I felt like I had to explain that reason

I won't. So, I'm back, picking up more or less where I've left off with the inane chatter and observations. My apologies to the two (maybe three?) people who read this somewhat regularly.

A thought on 1 Cor 15:14-19

This passage has always made me think of the danger in misquoting things. Compare the straight quotation:

¹⁴And if Christ has not been raised, our preaching is useless and so is your faith. ¹⁵More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him if in fact the dead are not raised. ¹⁶For if the dead are not raised, then Christ has not been raised either. ¹⁷And if Christ has not been raised, your faith is futile; you are still in your sins. ¹⁸Then those also who have fallen asleep in Christ are lost. ¹⁹If only for this life we have hope in Christ, we are to be pitied more than all men.

And the cleverly quoted version:

¹⁴...Christ has not been raised, our preaching is useless and so is your faith. ¹⁵More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him ... the dead are not raised. ¹⁶... Christ has not been raised either. ¹⁷And if Christ has not been raised, your faith is futile; ... ¹⁹If ... we have hope in Christ, we are to be pitied more than all men.

Sigh, after a long delay

It has been far too long, again, since I last posted. Oh well. Here's a conversation I had tonight with the missus:

M: Oh by the way, I'm sorry for whacking you in the head so hard earlier?

A: What?? When?

It really was unintentional.

A good vid about science

Check this out.

Science doesn’t have the answers to everything we would like to know about reality. What it does have is the most reliable answers and the most reliable ways of looking for answers. When one adopts scientific principles and procedures, one is saying, “I want to understand things as they really are, not simply how I might want them to be.” Science rewards our genuine curiosity, enabling true learning and discovery. It allows (indeed thrives on) openness to new ideas, while fostering a self-critical approach that prevents that open-mindedness from sliding into gullibility. It gives us access to real-world evidence, rather than encouraging us to accept the unreliable testimony of people whose motive may be to exploit us.

Science allows us, with more certainty than any other approach, to distinguish between true and false claims. Because of this, science leads us along the surest and most intellectually honest path to genuine knowledge about the universe in which we live.

Failure Mode: Calculator

I need a new calculator. This is my poor calculator's pitiful attempt to display a screen full of 8's.

Not surprisingly it was hard to get a good snap of the LCD in a dark room with a hand held point and shoot cam so that pic has been desaturated and unsharp masked. As you can see quite a few of the segments are out. Poor thing.

On the bright side (no pun intended), the physics of how LCD's work is a pretty demonstration of the polarization of light. I thought this was interesting (page 6):

Manufacturers of existing large LCDs often reject about 40 percent of the panels that come off the assembly line. The level of rejection directly affects LCD price since the sales of the good LCDs must cover the cost of manufacturing both the good and bad ones. Only advances in manufacturing can lead to affordable displays in bigger sizes.

Don't you hate

those blogs where all they post about are the stupid surveys and quizzes they take? I sure do. So without further ado, my latest quiz result:

Between 50 and 100 monkeys

I'm most like Between 50 and 100 monkeys.

Take the 'How many angry monkeys could you take in a fight?' quiz!

Make your own Quiz!

Take More Surveys

Screwed

http://kevan.org/froytest.cgi

The Froy Marriage Test

Froy Marriage Rating = -1304

"Generally speaking, no woman with an FR of under 250 can be recommended, especially to our less experienced friends. FR-minus women are out from the start."

Approximate Risk of Marriage = 100%

Yeah. I'm screwed.

Which NetHack Monster Are You?

|...+#
|.e.|
#+...|

If I were a NetHack monster, I would be a floating eye. I see and sense absolutely everything that happens around me. I just don't do very much about it.

Which NetHack Monster Are You?

This is so, so sad.

A Toast to Richard Hammond

A Beautiful Nutcase

I'm hardly an artist.

In fact, I'm not even close to resembling something that somebody might generously call artistic. My best freehand approximation of a straight line is more like... well... the back of a camel. Yet drawing is something that I truly aspire to be good at. So when I can get a little help from a computer I don't turn away the opportunity. Enter POV-Ray, the persistence of vision ray tracer.

To use POV-Ray you write a description of your scene in an easy to learn Scene Description Language or SDL, which vaguely resembles the C programming language. Then POV-Ray processes the scene description to produce an image.

This is what I, a complete amateur, produced after about an hour of playing with SDL:


If you want to see what real artists can do with POV-Ray I suggest you check out their Hall of Fame gallery. Warning: be sure your chin is over a soft surface. It will drop.

First post (again)

It has come to my attention that a few people actually read my blog (*shock horror*) and I haven't posted for far too long. This is what I do:

1. Start a project.
2. Get distracted.
3. Drop the project.
4. O(1) months later, feel sad about dropping the project.
5. Return to step 1.

Step 2 in this case was the Christmas/New year holidays. So, my friends, this is for you: step 5. Consider this my first post of the new year.

Mathemagical Goodness

It's rare that I see a bit of maths and am just blown away. Tonight I stumbled upon Wallis product formula, or more specifically, its derivation and literally just thought "wow, that's amazing." Now, the Wallis product formula is something I have seen before, several times, but I just never paid it much attention. Now I see that it's so beautiful and so simple, no wonder it was worked out in 1655.

The basic idea is this. We know that the sine function has a well behaved Taylor series (it is an exponential function after all) so it makes sense to treat the sine function as the limit of a sequence of polynomials. The same logic works (as far as I can see) for any function with an absolutely convergent Taylor series.

Now polynomials have two basic representations. They can either be written as a sum of monomials like or they can be written as the product of factors like where the r's are the roots of the polynomial and A is just a (constant) scaling factor out front.

Now, assuming that the sine function has such a product representation the trick is to find A. We already know the r's: the roots of the sine function are simply the integer multiples of pi. So we expect thatand we simply need to find the constant A. To do this we simply need to evaluate both sides at a particular value of x. It could get difficult to do this though unless we pick a nice value for x. Let's try x=0. But both sides are zero when x is zero so this is no good! Solution: divide both sides by x and take the limit as x goes to zero. This is a common trick really, and it works a treat here.

Now we know A. All that remains is to put it together. But notice that there is one term in the denominator in A for each term in the product from sin(x)/x. We can take a typical term and simplify it like this . So the product ends up being:



So there you have the Wallis product formula for the sine function. From there it is easy to find a product formula for various multiples of pi etc by just plugging in values and rearranging to suite.

I realize that it is pretty straightforward maths and rather boring for most people probably. However I just found the beauty and simplicity of this product formula for such a common function worth sharing. I also realise that the LaTeX in this post is ugly and inconsistent but I have no good technique for rendering equations for this blog at the moment.

I hope that, with a touch of holiday spirit, you might forgive this silly maths nut. And maybe even find a little inspiration.

I'm fairly certain...

that engineers refer to this as a "failure mode." This once spherical spray bottle crumpled as the result of: *drumroll* using it to spray water. *gasp* *shock* *horror*


Evidently you get what you pay for.

The Most Beautiful Principle in Physics

I realize that it is highly subjective to label one principle "the most beautiful in all of physics." If you ask ten different people you will likely get ten different answers, or at least three or four different answers. That said, I bet certain principles are more likely to come up than others. Here I will discuss a few together with some of the justifications that could be given for claiming them as "the most beautiful" in physics. The list of principles and their justifications is by no means exhaustive (on both counts) and input from others is appreciated. Here they are, in no particular order:

Conservation of Energy, Momentum, Angular Momentum, Electrical Charge, etc.

Conservation laws, in general, are very useful in that they tell us that certain quantities don't change. For instance, if you calculate the combined momentum of two objects before a collision you can be sure that the total momentum of the bodies after the collision will be the same provided there are no external forces acting on the system. This applies even if the nature of the bodies has changed considerably, for instance two cars deforming and breaking into pieces during a collision. Or say an electron and positron collide and annihilate, producing two photons. Momentum is still conserved even though the nature of the particles involved changes completely during the collision.

Conservation laws allow us to calculate the outcome of many processes (or at least severely restrict the range of possible outcomes) without having to understand the internal details of the process at all.

The ultimate origin of conservation laws is intimately related to the next principle...

Symmetry in Physical Law

Symmetry is the idea that there are operations that can be performed upon something, such that afterward the thing looks the same as it did before. Symmetry in physical law is then the idea that the mathematical equations of physics are invariant under certain groups of transformations. (Here group is a technical term for a set of algebraic objects which obey certain laws of combination. Group theory is the natural way to study symmetries mathematically.)

Symmetry in physical law appears at first glance an apparently empty concept. After all, the form of the laws doesn't change after the symmetry operation, so what does that tell us? Well, it turns out that, so far, every result of physics is derivable from a symmetry principle. This is truly incredible, and I think the implications of this have yet to filter through to the undergrad level, although the result itself has been known for many years.

Because of a mathematical result called Noether's theorem every (continuous) symmetry of physical law is directly related to a conservation law. For instance:

• The conservation of energy is a result of the symmetry of physical law under translations in time.
• The conservation of momentum is due to the symmetry of physical law under translations in space. This, incidentally, explains why energy and momentum are so closely related in relativity: it's just because space and time are so closely related in relativity.
• The conservation of angular momentum is due to the symmetry of physical law under rotations. The tricky bit here is that you can tell when you are rotating, but not that you have rotated. The rotations considered must be constant in time in order to get the right symmetry group.
• The symmetry of physical laws under "boosts" (changes of velocity of the reference frame) results in the conservation of a quantity which, as far as I'm aware, lacks a popular name but is nonetheless conserved. It equates to the law that the center of mass of a system moves uniformly in a straight line (in the absence of forces).
  
• The conservation of electric charge is related to an abstract (i.e., "purely mathematical") symmetry operation called U(1) gauge symmetry. It is not a symmetry like translations or rotations in space. It is a transformation of an abstract quantity called the phase of the wavefunction - a quantum mechanical thing that is hard to describe in words (although the mathematics is unambiguous). A truly remarkable thing happens when you try to quantize a theory involving a gauge symmetry, which will be discussed under the Quantum Field Theory heading.
• Other gauge transformations based on the SU(3)xSU(2)xU(1) symmetry group of the standard model result in conservation laws for quantities which are less well known, such as weak hypercharge and color charge etc.

The question is: is nature symmetric under every symmetry group? Evidently not. The Galilean group of transformations under boosts was replaced in favor of the Lorentz group by Einstein (more precisely, by Lorentz, Minkowski and Poincare based on Einstein's insights). Other symmetry groups have been tried and found wanting, or only approximately correct.

A famous example of this is the once posited SU(2) iso-spin symmetry of hadrons. This resulted in a theory of the strong nuclear force that is only approximately accurate. However, as this theory is considerably simpler than the currently accepted theory (quantum chromodynamics) it is still sometimes used today as an approximation in various situations.

So the question is, how do we decide which symmetry groups to use in the description of nature? Answer: experiment.

Stay tuned for a follow up post including the action principle (my personal pick for most beautiful in all of physic), quantum field theory and possibly other things...

A Little Story

From this blog comment on Bad Astronomy:

A burglar broke into a house one night. He shined his flashlight around, looking for valuables, and when he picked up a CD player to place in his sack, a strange, disembodied voice echoed from the dark saying, “Jesus is watching you.”

He nearly jumped out of his skin, clicked his flashlight off and froze. When he heard nothing more after a bit, he shook his head, promised himself a vacation after the next big score, then clicked the flashlight on and began searching for more valuables.

Just as he pulled the stereo out so he could disconnect the wires, clear as a bell he heard, “Jesus is watching you.”

Freaked out, he shined his light around frantically, looking for the source of the voice. Finally, in the corner of the room, his flashlight beam came to rest on a parrot. “Did you say that?” he hissed at the parrot…

“Yep”, the parrot confessed, then squawked, “I’m just trying to warn you.”

The burglar relaxed, then enquired, “Warn me, huh? Who the hell are you?”

“Moses,” replied the bird.

“Moses?”, the burglar laughed, “What kind of people would name a bird Moses?”

“The same kind of people that would name a Rottweiler, Jesus.”

Quotable

Wife: "Destruction causes distraction. And distraction can cause destruction."

Me: "Wow. Wise words."

Wife: "You can quote me."

Me: "I just might."

What I want to know

is why an argument against evolution is an argument for special creation?

I mean evolution may be wrong (let's look at the evidence), but even if it is wrong why do people assume then that God created everything as is a few thousand years ago?

Who says there only two options?

A Thought on Luke 15:3-7