Friday, January 24, 2014

That's Not an Explosion...

There is a supernova happening in the neighborhood. Actually, it happened about 12 million years ago but we get to see it now, for a couple of weeks. It seems like a busy neighborhood.

Sunday, January 12, 2014

Cheap Digital Microscope has plans for a lens and stand that lets you use your smartphone as a digital microscope. They claim up to 175x magnification (with two lenses, up to 375x!) That is enough to look at onion cells. This is a maple seed pod at only 60x.

Project cost: $10

Saturday, January 11, 2014

Brown Dwarfs Detected

A brown dwarf is not like a white dwarf: on the death march of a real star. A brown dwarf is a star too small to kickstart full fusion, too small to emit light, but big enough to emit energy (as infrared) for billions of years and fantastic enough to have liquid iron falling from the sky as rain. A Canadian team is using the Spitzer IR Space Telescope to study them.

Monday, January 6, 2014

Video Analysis
If you can take a video, you can use that video to measure speeds and accelerations. The tool involved is called "video analysis software" and there are free versions that seem to work pretty well. After looking at a few, I have comments on a smaller few:

1. Tracker: My favorite so far. It is free, computer-based, open-source and looks transparent and powerful, for example:
  • Fixed or time-varying coordinate system scale, origin and tilt.
  • Multiple calibration options: tape, stick, calibration points and/or offset origin.
  • Switch easily to center of mass and other reference frames.
  • Protractors and tape measures provide easy distance and angle measurements.
  • Define custom variables for plotting and analysis.

2. Kinovea: a free, open-source sports analysis software with some good analysis tool including video magnification, slo-mo, data export to spreadsheets. The output looks beautiful

3. Vernier Physics: a $5 app for iPhone & iPad. Vernier is popular and looks convenient for people who already use iPhones. But it requires you to:
1. not move the camera and
2. mark each frame manually.
3. You can't export your info to a spreadsheet.

Update(Jan'15)-Destin from Smarter Every Day shows how to analyse a grasshopper using Tracker. If that was a little fast, watch his tutorial. (Destin has linked all you need in the "show more" box of the first video.  When I tried repeating his work, the windows version of Tracker wouldn't work on every computer but the ".jar" file did. On some computers Destin's You-tube video (step #3) worked. On others, only Quicktime worked. Try stuff.