Tuesday, June 29, 2010

Sleep deprivation may have been involved.

Okay, O.W.L. progress time. Here's what I turned in for my Charms O.W.L. 50% submission, which is due on June 30 (with the completed O.W.L. due on July 31).

Hello, Professor! This is CraftyGryphon, First Year Slytherin, turning in her 50% of her Charms O.W.L. I had some figuring to do to see if I'd reached the 50% mark, and I believe I have done so.


At 110 chart rows

First, the unreliable math part. The finished diameter of the blanket is stated to be 72" (six feet), so the radius of a finished blanket should be half that, or 36" (three feet). The main blanket, excluding the cast-off edging is 140 rows of lace. Since I knit loosely, I'm not going to count the edging (and yes, I expect to have a humongous blanket at the end of all this). Those 140 rows should average out (lace rows & knit-only rows) to three feet. Thus, 50%, or 110 rows, will be roughly 18", or a foot and a half. I can't actually use this as a measure, since I was at 18" diameter, unblocked, at the end of Chart D! (On the other hand, at the 50% row, my unblocked radius was 28" - so I can calculate up that I'm going to have a blanket with a 74" diameter - which is pretty darned close to what it should be!)


No, wait, that's not right. I must invoke Pi. With Radius squared, and all that... so, roughly, so every time you double the radius of a circle, you increase the surface area by roughly 4 times. Um. So... if the finished radius at 140 rows is 3", then if I'm at 110 rows... um... Wait. Let me try this again.

I'm at approximately .75 of the final radius (slightly over, in fact). So, there are four radius units; each time the radius doubles, the surface area quadruples. From .5r to r, a increases to 4a. So the area for the first quarter is increased fourfold by the time the second quarter is finished, then fourfold again by the time the blanket (less edging) is done. Hmmm, I'm actually gonna have to do math here. Okay, Pir2. 1 unit = 35 rows. So, if the area for the first unit (quarter) of the blanket is Pi 12, the second is Pi 22, the third is Pi 32, and the fourth is Pi 42. Or, rounding, 3.14(x)sq, 12.56(x)sq, 28.27(x)sq, and 50.27(x)sq, where x is the base unit of radius (e.g., "4cm" or "20 inches") and sq is just my shorthand to remember that it's going to be "square cm" or "square inches" because it's area now, not length. But you can see: 3-ish quadded up is 12.5-ish; 12.5-is quadded up is 50-ish. Check. The 3/4r mark, though, is slightly OVER half the area of the finished blanket (less edging) - but, given the stated measurements of the edging, the area calculated using 3/4r mark is actually just a tad over 50% of the final area, which still puts my current 28" radius at 2463 square inches (which is over half of the projected final area - 36" gives 4071 square inches). (This means that my original, less mathematically correct method was a close enough estimate that I could've gone with it and saved my brain some hurting.)

I'm willing to go with that, but I'd like to make cert, maybe measuring by yardage & weight will work? I have a pattern which requires 1,800 yards of yarn for a blanket. I have four skeins at 560 yards each (total of 2240 yards). I have completely used one skein, and am a good bit of the way through the second.


By weight, my needles and markers weigh approximately 23g. My blanket, needles and markers weight approximately 412g. A ball of yarn weighs 237g. I have 71g left of the ball I'm currently knitting. So, I have approximately 403g of yarn in my blanket this far. Since each ball is 560 yds, then a 100 yards of yarn is 42g; so, if my blanket weighs 412g, I have used approximately 980 yards of yarn. This puts me over the "required" amount of 900 yards = 50% done.

Finally, according to the Girasole Tracker I'm using (and which, honestly, is keeping me going with its pretty little checkmarks letting me know that yes, the endless going-around-in-circles is actually resulting in More Blanket), the fifth row of the second repeat of Chart E puts me firmly at 51%. Here's a current screenshot of my personal chart:


I firmly believe I have crossed the 50% mark at this point. The Girasole Tracker indicates that the knitted edging bind-off counts for approximately 15% of the blanket, so I am, at this point, about 63.5% of the way through the body of the blanket, and 54.1% overall. (Really, I think the Girasole Tracker is the Best Thing Ever!!)

I hope this submission meets with your approval, and that I will be marked "50% complete".

1 comment:

Your tracks here...