Still no Moon Colonies

Here’s how I was marking the occasion, 48 years ago:

Shot off my parents’ B&W television

While we’ve done amazing things with remote sensing and with robotic exploration, we haven’t done much more with manned exploration. Given the success of the robots, we couldn’t have gotten that much information for the same money with men. But as somebody who grew up on “the conquest of space” it’s still a major disappointment.

I have several rolls of such shots. They’re all Kodak Tri-X, bulk loaded, shot with my mother’s old Bolsey 35 I believe (I didn’t get my Miranda Sensorex until December of 1969). Developed with stainless steel tanks in a dish pan down by the laundry sink, contact printed in the waterless darkroom the other side of the basement.

The white bands diagonally across many pictures shows that the shutter speed of the camera wasn’t well-enough synced to the scan rate of the TV. The TV scan rate would be extremely accurate or the picture would be complete hash, so the shutter was off.  This was a leaf shutter, not a focal-plane shutter, which affects the symptoms.

This was roll 108; I started the numbering system at 100 to make room for filing older negatives as I found them and organized them.  This was so long ago that the negatives were in glassine sleeves.

Glassine sleeves!

A few of the individual photos:

Survivorship Bias

Abraham Wald
Abraham Wald

Abraham Wald is the mathematician who took one look at the charts showing where planes getting back from missions had been damaged, and realized that the parts that needed extra protection were the undamaged areas.

Great article (from 2013) on “survivorship bias”, including the Abraham Wald story and quotes from Mike Johnston’s The Online Photographer, here.

Note to self: maybe I should keep track of David McRaney.

SkyCube crowd-funded satellite nearing launch

Well, by some definitions it was launched weeks ago. It’s on the ISS, and they’re prepar2014-02-20_10h05m01sing it for deployment with a group of other tiny satellites.

I helped (slightly) to sponsor the SkyCube satellite via their Kickstarter campaign. Being able to tweet from space briefly, and being able to direct the camera to take images occasionally, has a pretty high cool value.

Year of our moon landing 43

I was 15, living at home, and working in the Carleton computing center that summer. We had a B&W TV, but that’s all they were broadcasting from the moon anyway.

I remember making a reel-to-reel tape of the commentary of the landing, and shooting many B&W negatives of the TV screen as things progressed. I still have the negatives, but now we have access to much better pictures from the cameras the astronauts had with them.

Heat Output of my Stove

Since we’re shopping for a new stove, and one feature I find attractive is a higher output burner (particularly for stir-frying), it occurred to me to check what the heat output of my existing big burner is.

Stand Back, I’m Going to do Science

Our Ancient Magic Chef Stove

My burner, on high, raised 64 fluid ounces of tap water (measured in a single large Pyrex measure) from 67°F to 130°F (by my new Taylor instant-read cooking thermometer; scale is 2 degree intervals, so the 67 is interpolated by eye) in 4 minutes (by my Casio stopwatch). I pre-heated the pan slightly, the water sizzled when I poured it in. This both accounts somewhat for the mass of the grate and the pan needing to be heated, and eliminates the need for three hands to turn on the burner, start the stopwatch, and pour in the water simultaneously.

Bowl of Plenty says I can ignore the difference between distilled water and tap water, and that water weighs 2.0803 pounds per quart.   (Yeah, “a pint’s a pound” is off by .04015 in modern measurements.)

Stove burners are rated in BTUs/hour, which they usually just call “BTUs”.  Reading between the lines, they’re rated by the theoretical heat production of the volume of gas they handle. Actual heat production depends on combustion efficiency. Then there’s heat transfer to the cooking vessel. Then, in my experiment, there’s heat loss to radiation, air convection, and water evaporation. I make no attempt to account for those. Reading various online articles,  people seem to think heating measured the way I did it will be about 1/2 the BTU rating of the burner.

The BTU was traditionally defined as the energy needed to raise one pound of water by 1°F at atmospheric pressure (which is about 1055 joules). (There are BTU definitions at different temperatures, which give slightly different results.)

So, 2 quarts × 2.0803 pounds/quart × ( 130 – 67) degrees = 262.1178 BTUs.  4 minutes is 1/15 of an hour, so that’s 3,932 BTUs/hour. (Yeah, I carried all the meaningless digits through to the end and then rounded.)

The rumored 2x efficiency factor from rating to reality would mean that my burner would rate a bit under 8,000 BTUs/hr.

Normal burners of modern stoves rate 8,000–12,000 BTUs/hour, so that passes sanity check.

And it also suggests that a modern stove with a burner rated at 17,000 BTUs/hr would be a LOT better for stir-frying, or for cooking pasta for that matter.

I would have felt really stupid buying a new stove with a spiffy keen high-output burner, only to discover it produced less heat than my old burner did.

So, do ya think this might have been easier in metric units?  (I could have done it that way, just translating the temperatures I measured, and then translating the BTU ratings of the new stoves back to metric. But once I got done researching the definition of BTU and the density of water, it seemed like more fun to use them directly.)

Also, this is yet another example of a practical math and science problem people can encounter around their home.