The Puddle

At 0830 it was too dark to read so EKA shut "MATLAB for Engineers" and got lost trying to find the bus stop. It was colder than yesterday and starting to get windy and he wished he'd brought a second coat. Douglass campus is the only one he knew he could get lost on, and nothing looked familiar anymore.

Finally he came to the Puddle, where he knew there was a REXB stop on the other side. Walking around the water he tripped on a low stone bench and dropped the MATLAB book into the Puddle. EKA stopped for a moment. It wasn't such a great book, but he didn't like to just leave garbage in the pond. As he stood there trying to think of a way to fish it out, a person emerged from the site of the book's weird misfortune. In front of EKA was a man with leaves and branches growing from his head, vines winding around his legs dangling into the water. In his arms he carried another person, a man in his twenties who was either sleeping or dead.

EKA, unsure of how to react, stood watching until he saw the bus's luminous windows in the corner of his eye. About to forget MATLAB and head for the bus, EKA noticed that the sleeping cargo was his MATLAB professor Blase.

The three of them stood that way for hours. Buses came and went, the night turned into morning, but no one would find EKA; he never told anyone where he was going and did not carry a cell phone. Even his roommate wouldn't wonder, since Allen always went to bed by midnight and expected EKA to be gone then.

The sun was up now, and both EKA and Blase would have to be in SEC-110 soon for MATLAB lecture. Sensing class would not meet today, EKA took the bus home and went to sleep.

You seem like the type of person who would...

This idea is due to someone who wishes to remain anonymous.

It's an icebreaker game: you take turns saying to someone else "You seem like the type of person who would ..." and finish the sentence. The more you offend people the better it breaks the ice.

"You seem like the type of person who wouldn't use soap."
"You seem like the type of person who would write about dumb games like this."

The 'Math is Always Right" Principle

This idea is due to Charlie Loelius and Owen Healy.

The Math is Always Right principle:

When a mathematical model and reality disagree, the interpretation is that the math behind it is right, but it is applied incorrectly to the situation.

Corollary:

This leads to the impression that math is always right.

Corollary:

This leads to the impression that reality is always wrong.

Example:

You predict the time for bottle of ketchup pushed off a table to hit the ground. The number is close but not quite right. The math behind the model (quadratic equations, the real number system, calculus) is considered to be fundamentally valid, but other factors (air resistance) made the model not completely accurate in this situation.

The interpretation you did not use is that the model is fundamentally right (takes into account the entire physical situation) but the math behind it (the real number system) is wrong in this case. Either interpretation could theoretically have been used to resolve the situation.

Another Example:

Catholicism = 2
Protestantism = 3
Judaism = 5

Therefore Catholicism + Protestantism = Judaism.

The math is clearly right, but the application to this situation is absurd.

Exact Numbers

Recently I have been counting steps as I walk. I pick particular short stretches along frequently traveled routes and count each time I walk them. The numbers vary quite a bit. I can't say, for example, that a stretch of sidewalk is 54 steps long, but I could give a pretty good guess of the mean at 54 and the shape of the distribution.

It's natural to believe that the exact number of steps does not exist, because once you walk it, it vanishes. Each time you try to count it, you will get a different number. The distribution eventually takes a characteristic shape, but each time you walk it, the outcome is unpredictable.

Now another counting problem. Count the number of ants in New Brunswick. You can't actually go and find every single ant. Even if a team of 100 people committed a year to it they wouldn't find every single ant. You'd have to get some kind of an estimate. And it wouldn't be exactly right, and every time you did it, you'd get a slightly different estimate.

Now the question is, does the number of ants exist? First, a slightly less weird question: is there any way to observe the exact number of ants directly? My inclination to this question is no, simply because I haven't thought of a way to do so. Then a slightly harder question: is there a way to observe the exact number of ants indirectly? Another way to put it, is the number of ants divisible by three, and how would we ever know? The question this is getting at is, is there any way in which whether the number of ants is divisible by three will affect our experience in a way that is observable to us? This is the really careful way of asking, is the world in which the number of ants exists any different than the world in which that number does not exist? Which is yet again a really careful way of asking, does the number of ants exist? Again my inclination is no, but only because I haven't thought of a way to make it exist.

Anyone who thinks we live in a deterministic world hasn't looked around them recently enough.

Desk Writing

SEC-205 has some of the best writing on the desks. Here is a sample:

Hello person sitting at this desk
Hello, o you fr
Hello to both of you.
Hello you three.
Goodbye
You say goodbye and I say hello
ppl, go see Forgetting Sarah Morgan...
Ridiculous
Yeah I wanna see that (and Ironman)
I like bunnies. <-- bunnies? No one likes bunnies!
Hello you four. Though I will be parting my seat forever, I wanted to let you know your messages were entertaining. I shall take your advice and see the movie. Farewell fellow desk writers.

It's not goodbye, it's _I'll see you later
Farewell to you all !! :)

Relativistic Asteroids

I have long been bothered by the lack of relativity in the arcade game asteroids. This problem has been addressed! See Relativistic Asteroids.

By the way, does anyone know a portable way to embed an applet in xhtml 1.1?

Stall Writing

I found some beautiful writing in the bathroom in Scott Hall. It was in several different handwritings.

A MAN WHO HAS A
"WHY"
TO LIVE
CAN DEAL WITH ALMOST
ANY
"HOW"

A MAN WHO HAS A
"WHAT"
TO DO
PROBABLY WON'T
TRANSCRIBE
FORTUNE COOKIES
INTO
BATHROOM STALLS
Unless their
"what" to do
is to
transcribe
fortune cookies
into
Bathroom
stalls
I think we all need
a hobby
THIS IS MY
HOBBY
THIS IS MY
PASSION.

Efficiency of a Microwave

I wanted to find out what percentage of the power supplied by my
microwave ends up in the food as heat. It was tricky because I did
not have a thermometer. I used the following procedure.

Measuring input power:

1. Unplugged the refrigerator and checked that no computers or the
   stove were running.
2. Timed how long it took for the wheel on the power meter to
   revolve once.
3. Put some chili in a bowl in the microwave, turned it on for three
   minutes.
4. Timed how long it took for the wheel on the power meter to
   revolve once

Measuring output power:

1. Emptied a tray of ice into a glass bowl and added
   room-temperature water.
2. Waited till the water felt as cold as the ice.
3. Poured the water through a strainer into a measuring cup. Measured
   the volume of water.
4. Poured the water back into the bowl. Covered the bowl with
   a lid.
5. Put the bowl in the microwave and set the timer for 1 or
   2 minutes. Waited for the bell to ring.
6. Took out the bowl, poured the water through a strainer into the
   measuring cup and measured the volume.

Data

Input power

Trial	Time with Mic. Off (s)	Time with Mic. On (s)
1	74	17
2	77	19

Output power

Trial	Time (s)	Init Vol of Water (mL)	Final Vol of Water (mL)
1	120	500	600
2	120	125	330
3	60	330	410

Calculations

Power meter formula from

Michael Bluejay.

Base Power = ( 3.6 * 7.2 ) / (Time with Mic. Off)

Total Power = ( 3.6 * 7.2 ) / (Time with Mic. On)

Input Power = Total Power - Base Power

This gives 1.17 kW, 1.03 kW. The average is 1.1 kW.


Output Power = ((Final Vol of Water) - (Init Vol of Water))
* (1.0 g/mL) * (333.55 J/g) / (Time)

This gives 0.28 kW, 0.60 kW, 0.445 kW. The average is 0.44 kW

This gives an efficiency of 40%. Unfortunately, the 90% t confidence
interval for the Output Power is (0.17, 0.77) so more trials are
needed.