Archive for June 3rd, 2009
These caissons always weigh the same whether or not they are carrying their combined capacity of 600 tonnes (590 LT; 660 ST) of floating canal barges as, according to Archimedes’ principle, floating objects displace their own weight in water, so when the boat enters, the amount of water leaving the caisson weighs exactly the same as the boat. This keeps the wheel balanced and so, despite its enormous mass, it rotates through 180° in five and a half minutes while using very little power.
Short time-lapse video of the wheel in action
An interesting graph of life expectancy vs per-capita income, for a bunch of different countries around the world. What is so trés cool is that you can animate it to run it from 1800 to the present. France does a meteoric rise very early on with no change in income, war participants take hits in life expectancy, and basically the whole world does the Time Warp (it’s just a jump to the left) in 1929.
NOTE: This Instructable contains graphic images of Gummi Bear surgeries.
One of the questions I was asked in my most recent adoption was what I would do if I were not a physicist. I’m pretty sure I would do something in science, and I have an interest in evolution and paleontology. The stumbling block to going in that direction was the squishy part of biology — when I was in school, I was pretty sure animal dissection would start by making me weak-in-the-knees, followed by me throwing up, and I had no desire to test that prediction. Consequently, I haven’t studied a whole lot of biology, including entomology.
But dragonflies are pretty fascinating. They don’t fall under the “bugs to be avoided” category — not gross house-invaders, nor do they want to sting me. I had no idea that they flap their sets of wings out of phase, though it makes sense (if it were in phase, why not just have a bigger wing?) But I have some shots where it looks like maybe the two sets are at slight different frequencies, so the phase changes. I also didn’t realize how much they glide when they fly. And the flapping is low enough in frequency that it shows up well on a high-speed camera — a much lower pitch than many other insects.
It’s also really hard to pan a camera to follow them. I think I saw six distinct species; these were the biggest and flew high, while a few others tended to hug the ground, and yet others I only saw in the woods.