Cosmos Computed

Photos of seeds from yesterday, to scale. The onion is the one on the left. A couple of days ago I planted 3 seeds in a clear glass jar, so I could watch them germinate. 2 of the seeds came from one of my basil plants, and the other came from a green onion plant. This is partly a test on the quality of my home-grown seeds, but also a fun gardening activity; after all, who wouldn't like to sprout  some seeds and watch them grow? Here's how you can make your own sprout jar: 1. First make sure you have some seeds you can use. Popcorn kernels work very well, if they haven't been popped yet; the better they pop, the better they grow. You can also use dry uncooked beans. 2. Acquire a small clear tube of some sort. I used an empty spice jar with the label removed.  3. Fold and/or cut a paper towel until it is as wide as the jar is tall. Then roll it up and put it inside the jar. Try to make the paper towel tight against the sides of the jar. 4. Add seeds to the jar. Place the seed

Yesterday I learned about something really cool called a Halbach array. It's a special arrangement of magnets that has a magnetic field on one side, but not the other. The array and its effect were discovered in 1973 by John C. Mallinson, but it was named after physicist Klaus Halbach, who invented the array 7 years later - not knowing someone else had already gone to the trouble. Halbach array, showing approximate field lines. The way the Halbach array works is similar to a bunch of lined up horseshoe magnets. There are North and South poles, but they are all on the same side of the row. Horseshoe magnets are clumsy, so in the Halbach array, regular bar magnets are used instead. The magnets are oriented so that their magnetic fields match those of the horseshoe magnets they're replacing; that way, the effect is nearly the same. A perfect Halbach array is only magnetic on one side, greatly reducing stray magnetic fields that can interfere with other equipment; and since the mag

One day in Arizona, I made pancakes. The pans were a little different than I was used to; I normally use a buttered cast-iron skillet to fry my pancakes, but the apartment we were staying in didn't have any of those. As far as pans went, all they had were stainless steel frying pans - which are very different from cast-iron skillets. When I was heating the pans for the pancakes, I couldn't tell how hot they were. I put my hand over one, but felt very little heat - probably because it didn't radiate much heat. So I left the pans to heat up more. Finally I decided to try something else. I got my hands wet, so I could splash some water on one of the pans. If the water bubbled and boiled, that would mean the pan was hot. I splashed some water on. It didn't boil; instead, as it hit the pan, there was a dull clink , and the water turned into a bunch of tiny balls that rolled around on the pan, bouncing back and forth from one side to the other. Now THAT was different. What wa