Monday, December 08, 2008

Damn Hot

We're looking to build a new sugar shack at work and that made me think about making maple syrup. When I teach my programs, I demonstrate the art of rock boiling. For rock boiling I build a fire and let igneous rocks (mostly basalt) sit in the middle for a couple of hours until they glow orange. I then transfer the rocks from the fire to a hollow log full of water to show how people boiled maple sap before they had metal buckets. The heat of the rocks transfers to the water and it goes into a furious boil. It is really cool but one of the questions I always get asked is how hot are the rocks? I knew they were over 212° F since they made the water boil and I figured they were way over 212 since if you put rocks in boiling water they don't start to glow. I tried to find a website with a reference to how hot rocks have to be before they glow but found nothing. Then I tried a new approach and found the following on a website about volcanoes.

(emphasis mine)

"By way of its color, incandescent rock gives a crude estimate of temperature. For example, orange-to-yellow colors are emitted when rocks (or melt) are hotter than about 900 degrees Celsius (1,650 degrees Fahrenheit). Dark-to-bright cherry red is characteristic as material cools to 630 degrees Celsius (1,165 degrees Fahrenheit). Faint red glow persists down to about 480 degrees Celsius (895 degrees Fahrenheit). For comparison, a pizza oven is operated at temperatures ranging from 260 to 315 degrees Celsius (500 to 600 degrees Fahrenheit)."

So there you have it. Glow will persist in rocks down to 480 Celsius which means they will start to glow around there too. I've gotten them hot enough to do more than just faintly glow but a faint glow is pretty typical. 480° C equals 895° F and from what I gather, hardwoods in a fireplace burn around 900° F so that jives with the number above.

I guess what I'm trying to say is, "Hell no I'm not picking that rock up with my bare hands."


Thursday, December 04, 2008

The Barred Owl Returns...

Last year I posted about a barred own that showed up outside my work window. It's that time again.

Here's a photo I took today from inside the building looking out across the yard and septic field.

Can you spot the owl?

How about now?

How about now?

I'm guessing this is the same owl. Go back and check out the photos from last February, that's the same tree, but the owl is on the next branch down.

This is a nice opening in the forest so the owl must be hoping to spot some small mammal running under the snow. On the other hand. About 75 feet away on the opposite side of the field is the mew with our female captive barred owl. We are getting near mating season.

Monday, December 01, 2008

Alkaline Food

I spoke with my friend Awe lately about food as he used to be a food scientist. We were musing over hte fact that while there are a lot of acidic foods in our diets there are relatively few to no alkaline foods. This is easily explained by two important factors. First off, we like the taste of acidic foods. Foods with a low pH are acidic and create a sour taste. While in the extreme, sour is overwhelming, in moderation it provides the tangy bite in ketchup (acetic acids from the vinegar) and the tangy refreshing bite to lemonade (citric acid in the lemons.) The second factor to consider is a bit more practical. A low pH environment is good for food preservation. This brings up the interesting evolutionary question, "Do humans prefer acidic foods as an adaptive evolutionary strategy because tangy acidic foods are less likely to harbor pathogens?"

When trying to think of foods that are basic or alkaline, the only food he could think of was Lutefisk which is slightly alkaline. Not surprisingly, many people do not like the the taste of alkaline foods. Think soap.

I did a quick web search for alkaline foods and came up with this website.

This is a marvelous example of why you should always assume websites are written by hacks who understand very little science. This person recommends eating lots of vegetables which is probably a good thing but then goes on to say how fruits and vegetables are good alkaline foods. Want some examples? Here's what he has on his chart for foods that are "High Alkaline."

Lemons, Watermelon, Limes, Grapefruit, Mangoes, Papayas

Really? Really? LEMONS! LIMES? Lemons are one of the most acidic foods you can possibly find. Lemons have a pH of 1.8 to 2.3. For comparison, Battery Acid has a pH of 1.0 Any citrus fruit has a low pH due to the citric acid.

Moral of the story? Anyone can make a web page but that doesn't mean they know anything about science.