Category: Uncategorized

IMGP4074.jpg, originally uploaded by nakedtram.

Here is one of the cranes up close. Lucy stared at it intently through the rear passenger window of our car.

IMGP4108.jpg, originally uploaded by nakedtram.

On our way out of Carlos Avery (a state wildlife sanctuary about a half hour north of Minneapolis) we saw a pair of Trumpeter Swans. These large guys dwarfed the Canada goose that was swimming nearby. One was banded (Z85) around the neck. They spent most of the time with their heads under water. They’re stained slightly pink on their heads and bellies — I suppose due to iron or some other mineral in the water.

IMGP3920.jpg, originally uploaded by nakedtram.

Happy puppy!

IMG_2735.jpg, originally uploaded by nakedtram.

This is a variant on a popular triangular fractal, modified with hearts.. just in time for Valentine’s Day.

Download the source Adobe Illustrator CS3 file for your Craft ROBO (free!) here: http://andysblog.wpenginepowered.com/downloads/heart_fractal.ai

IMG_2733.jpg, originally uploaded by nakedtram.

This card was made using Craft-Robo! The heart twirls around while the lyrics to a popular song from the musical “Carinval!” scroll by in the cut-out windows.

Download the source file for free here: http://andysblog.wpenginepowered.com/downloads/love_world.ai

IMG_2739.jpg, originally uploaded by nakedtram.

“Be Mine” palindrome card. Created using Craft-Robo. Download the source file here

The pitch of a whistle is determined by its length, and the speed of sound (340 m/s).

To determine how long to make a whistle, you need to know the frequency of the desired pitch:

Based on A 440 (A5), you can determine the frequency of C5 (three half steps higher than A5) by multiplying it by 2^(3/12). 3/12 is 0.25, and 2^0.25 is 1.189. 1.189 * 440 = 523. Higher octaves are multiples of 2: 1046, 2092, 4084. ( units: Hz, which is also 1/s)

The length of the whistle is simply the speed of sound divided by the frequency:

C5 : 0.65
C6 : 0.33
C7 : 0.16
C8 : 0.08

It’s this last one that interests me — because an oboe reed is approximately that length, and it sounds “C” when blown by itself.

But curiously, an oboe reed isn’t 8 cm long — they’re usually 6.9-7.1 cm. What would account for this difference?

It turns out that the value for the speed of sound I used was for dry air at sea level at 60 degrees (F).

However, an oboe reed is blown, so the air moving through it is 98 degrees, and 100% humid. Calculating the correct speed of sound requires knowing the density of the air, and its adiabatic constant. Fortunately, someone has already calculated this. They give these values:

30°C 351.51
40°C 359.17

Linear interpolation for 37° gives us close approximation for the speed of sound through human breath: 357 m/s

Using this revised value, we find that our ideal oboe reed would be 8.5 cm. This is ever further from the actual length of an oboe reed!

So where does the additional 1.6 cm come from? If the pitch of the instrument was determined entirely by the length of the reed, then it would be impossible to influence the pitch of the instrument by how you play (e.g. your embouchure). I assure you, the pitch of the oboe is very easy to influence! Therefore it is clear that the musician is part of the instrument — Thus the extra 1.6 cm are coming from the resonance of the players mouth.

I upgraded to Lightroom 2 last week… so far, every single change that I’ve noticed has been for the better. It’s a remarkable improvement over what was already one of my favorite pieces of software ever.

From Daring Fireball

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Eric put up a snap of the about box. Can you find my name?

You can see how well we’re staying afloat next week by checking that live data report from the USGS:

http://waterdata.usgs.gov/nwis/uv?site_no=12355500

Dad is hoping for around 2000 CFS. Based on the data for the last 8 days, I think it should reach that just when we put in on the 31st. It depends on whether it rains in the next week, and how warm it is (which will influence how quickly the glaciers and snowpack melt). If it is a lot higher than 2000 CFS, it can make negotiating the log jams more treacherous. But also more exciting…

Speaking of melting glaciers, it looks like the mean water temperature is 15 degrees C. Which seems down right balmy for melted snow. But keep in mind the gage station is in Columbia Falls, and we’re going to be upstream of there. Closer to the source, and therefore likely to be colder water. I think Mike is bringing a wetsuit for the guy in the kayak…