## Sunday, March 28, 2010

### Overly specific quebec signs 1/2

In northern highways in Quebec they have periodic crossings of all sorts. The images on the warning signs are often extremely specific. For example the sign below, warns that logging trucks will be entering the road for the next 10 km.

This is what they actually look like in real life, the cartoon is surprisingly accurate.

They were also really good about giving information about the road - like when the next gas station is (251 km away).

or when the paved road turns into a gravel road (here at the manic 5 dam).

They also are kind enough to let you know that if a siren sounds near this dam you should probably find higher ground because the dam is presumably bursting . . . I suppose.

Next week I will post about the specific animal crossing signs from the deer family.

and Happy Pesach everyone.

## Thursday, March 25, 2010

### Mysterious Orange Reaction

I made a recipe recently which called for dried ground orange peel. Rather than buy some, we dried some orange peels and I ran 'em through the spice grinder. I ground more than we needed, and we are out of glass spice jars, so we put the ground peel in a disposable plastic container (like the ones that come with salad dressing at some restaurants). The following day, Stacy noticed that the container melted:
The bottom of the cup actually "melted;" it got stuck to the top of the spice rack.  It wasn't due to heat, I don't think. The plastic kind of went mushy and soft; the bits melted on to the top of the rack could be wiped off!

Here's a shot of the bottom of the thing after we peeled it off:

It was so soft, you could mush in the sides:
I honestly have no idea what caused this, but if anyone has ideas, I'd love to hear 'em!

## Sunday, March 21, 2010

### Spring break at the Manicouagan Reservoir

Two weeks ago I introduced everyone to the manicouagan reservoir crater from outer space. Now I will show you what it looked like up close last week.

A small herd of Caribou stroll along the lake surface, purportedly frozen 6 feet down.

There is the Manic-5 Dam, it is the worlds largest multiple arch and buttress dam (214 m tall and 1.3 km long), its hard to get a sense of scale from the photo.

There is one road that goes past it, Rt 389. It is an amazing road, well isolated from civilization but surprisingly well traveled even in winter. The road goes 561 km without a single city or town and only 3 gas stations. We did make it to Labrador city in the end.

Labrador city is just past the 52 Parallel.

## Thursday, March 18, 2010

### Marshak Elevator Update

So, the same remarkably clever person/group behind the hilarious signs on the out-of-service Marshak elevators [see here] have struck again.  This time, with a large sign, duplicated on this websitehttp://marshakelevators.com/404/
I've taken a screenshot of the 404 in case they take down that site, but in the meantime, check it out there, and be sure to click on those links!

From the comments on that site, it's unclear who exactly is behind the signs.  Maybe CCNY's administration is funnier than people have given them credit for.

## Sunday, March 14, 2010

### The system is down

We've been weathering quite a crazy storm the last few days.  We haven't had phone or internet since Friday (they got it back up this morning).  Our sump pump has been working overtime.
But two people were killed in Teaneck yesterday evening, hit by a falling tree.  Much of Teaneck is without electricity, without water, without heat.  Last night they declared a "State of Emergency" here and asked residents to stay inside.  It's pretty crazy.
I've been listening to the Teaneck Police/Fire/EMS radio feed [here]. Things are relatively calm at this point, but it's frightening to hear the fire department send out a call with the warning that there might not be water pressure when they get there.  Or the tons of calls about trees on leaning on wires, about to come down.
Here are a few pictures from the neighborhood.  Two blocks over:

And this is literally next door to where we ate lunch yesterday afternoon:

## Saturday, March 06, 2010

### Manicouagan Reservoir Crater

When driving around Google maps from space I noticed a strangely symmetrical circle. link

Its the Manicouagan Reservoir, known in French as Reservoir Manicouagan. A huge meteorite crater its tied for fourth largest diameter. In my opinion it is much more clearly visible than any of the other large craters on earth . . . well from space at least!

There wasn't always a lake there though, the Manic-5 dam makes this huge lake the fifth largest man-made lake on Earth (by volume). Actually, if you look for it, its so huge that you can find it on maps of North America and even some globes.

## Thursday, March 04, 2010

### Pan pipes in the Andes

I ride the subway to and from class a couple times a week, and every so often there's a band playing music from the Andes.  Usually, these bands have a least one guy playing a pan pipe, which is essentially a series of tubes stuck together.  When the musician blows across the top of a particular pipe it makes a sound.  Listen to the music here, for examplehttp://www.youtube.com/watch?v=GIXE-5NrC3o

In any case, the other day, when I stopped to listen, I began to wonder: Do these pan pipes sound different back in the Andes?

I'm going to try and avoid any serious physics/mathematics here, but there three important things to consider.  First, that in a pipe of fixed length, the frequency of a sound wave (i.e. the particular note you hear) that resonates in that pipe depends on the speed of sound.  Second, the speed of sound depends on the density of the medium it's travelling through, which in our case is air.  Finally, the density of air changes at different altitudes.

So, since the density of air is different at different altitudes, the speed of sound is also different, and therefore the frequency a pan pipe plays will be different.  Assuming I did my math right, the ratio of frequencies at different altitudes is equal to the ratio of the speeds of sound at the different altitudes.  So, the frequency of the pipe in the Andes $f_a$ is related to the frequency in the NYC subway system, $f_{nyc}$ by:
$f_a = f_{nyc}\left(\frac{v_a}{v_{nyc}}\right)$

Although there are ways of calculating the speed of sound at different altitudes, I just looked it up in a table (you can also enter any height, and this will calculate it for you).  The average altitude in the Andes is 4,000m, so the speed of sound there is 324.6 m/s and NYC is at approximately 0m so the speed of sound there is 340.3m/s. Thus, the frequency will be shifted down (lower pitch) by around 5%.

What this means, in practice, is that most notes will sound about semitone flatter in the Andes than they do in NYC.  For example, if this is how the music sounded in the subway:
This is how it would sound in the Andes:

So, the music you hear in the subways is not really authentic; it's a semitone high pitched.