Interesting Stuff

I have some wild rice. The instructions on it say to boil some water in a saucepan, stir in the rice, cover, reduce heat to a simmer, and wait a while. When I stir the rice into the boiling water, I also stir in some butter and a spice mix (sugar, powdered soy sauce, onion, sesame seeds, garlic, and some other stuff). I mix everything thoroughly, cover it (so I can’t see what happens), reduce the heat, and wait.

When the rice is done, I uncover it, and all the sesame seeds are in a ring around the edge of the pan. The ring is maybe an inch thick; the pan is about 8 inches in diameter. The butter and sugar are mixed throughout and not clustered in any place, but the other spices, like the sesame seeds, seem to be in higher concentrations in the ring and lower concentrations in the center of the pan. I have a gas-powered stove, if that makes a difference.

Why does this happen?

(found via the Skeptic’s Guide to the Universe)

The short version: British bird enthusiasts have (unintentionally) split a population of birds into two separate groups, and over the past 50 years they have slowly but surely been turning into two separate species.

The long version (copied here for fear that the original article will disappear):
Article behind cut →

In case you missed it, here are the other parts of the Will It Lens? series. I know I haven’t updated in a while, and I’ve got a huge backlog of pictures. So, part will be discussed here and I already have enough for another post as well.

Remember that all the safety warnings from the other posts in the series still apply here, though I don’t have anything new to add. Thanks for all the suggestions you’ve given us; we’ve tried some, and there have been quite a few good ones!

Improvements to our setup and more pictures of results →

If you’ve missed it, here are parts one, two, and three of our adventures with a 4’x3′ fresnel lens, along with a gallery of all the pictures.

Our lens arrived with a corner chipped off, so the lens company sent us a second one for free (which also had its corner chipped off on arrival, but we didn’t get a third for free). I’ve been holding off writing this post because I was hoping to title it “Episode IV: A New Lens,” but we still haven’t built the frame for the second lens or the frame for the mirrors that will reflect light from both lenses onto a single point. So, instead of waiting for that to happen, I’m posting the results I’ve already got.

The same SAFETY NOTES as before apply, as always. In lieu of new safety warnings (we haven’t had any new dangers come up!), I’ve got a few tips for anyone trying to duplicate this. Some tips for fellow lensers, followed by more pictures of results →

If you missed it, here’s part 1 and part 2 of our adventures with a 4’x3′ fresnel lens. As always, I’ve got a gallery of all the raw pictures, and this is a summary of the good ones.

The same SAFETY NOTES as before apply, with the addition that you shouldn’t eat any food you cooked in the same skillet in which you just cooked non-edible things (plastics, coins, etc). Also, we’ve upgraded our welding goggles, from a shade 5 filter to a shade 12, which is actually good enough that you can stare at stuff in the focal point. It’s not quite good enough to stare directly at the sun, but it’s darn close, and rumor has it that you can watch sunspots through this thing if you don’t look at them too long.

Last time, I left you with a picture of popcorn getting ready to be lensed. More results with more pictures →

In case you missed it, here’s part 1 of our adventures with the 3’x4′ fresnel lens.

Oh, man. I have lots more pictures. The same SAFETY NOTE as last time applies again, but with a few more additions. You should probably wash your hands after you’re done handling stuff in the lens. In particular, when you heat copper up until it turns black, you’ve probably made copper (II) oxide, which is a somewhat nasty irritant. I also make no guarantees about how many carcinogens we’ve made/touched/breathed, although so far I still feel healthy (no cancer in the past week!). Speaking of health hazards, if you use a frying pan to hold stuff, make sure it doesn’t have a Teflon non-stick coating! That coating will burn away and become a huge safety hazard (it’s mainly fluorine, and most fluorine compounds are toxic, volatile, and several other kinds of nasty; quite a few fluorine compounds were used as chemical weapons and precursors to sarin nerve gas, so avoid it at all costs). We got a cast-iron skillet, which is reasonably safe and inert, and it doesn’t melt until we break 1800K, which is very unlikely with our current setup.

Anyway, on to the results. with more pictures, of course. →

but this is pretty good.

A couple weeks ago, Dustin got a whole bunch of people to each contribute a few dollars, and we bought a four foot by three foot fresnel lens. It arrived earlier this week, and we’ve been spending our lunch hours out in the sun playing with it.

Explanation of the lens and safety note, followed by more pictures →

My father is a chemical engineer at a large company. He volunteers in an outreach program where the company gives him science demonstrations aimed at precocious elementary schoolers, and he periodically goes to schools and birthday parties and stuff to show how neat science is. One of the kits he does is all about cryogenics, where he gets about a gallon of liquid nitrogen (LN2), and demonstrates what happens to things when you freeze them really cold. He talks about how matter can be a gas, a liquid, or a solid, and how its properties change as it goes from one state to another and changes temperature (racquetballs become brittle, flowers become crumbly, small amounts of LN2 boil into large amounts of nitrogen gas, etc).

He did a demonstration a couple days ago, and still had some LN2 left over from it. Ordinarily he just pours the rest out on the street (it boils away quickly, and no one notices since air is already about 78% nitrogen). However, this time we convinced him to keep it around for a few days so we can try freezing other things. Some stuff about LN2, and some safety tips, followed by a bunch of pictures →