I'm curious. When it's not got the computer monitor behind it looks like it's vibrating at the same speed no matter what pitch I change it to, but when I look at the string in front of the monitor, it appears to slowly... sort of swim, like a sperm tail would, and it changes at different pitches. Why does a computer monitor do this?
2007-10-28 11:43:52 · 2 answers · asked by Chris 3 in Science & Mathematics ➔ Physics
A strobe, which accounts for the slow motion, but a bit more too. Slo-mo or stopped motion is due to standard strobe physics, a small or zero frequency difference between some small multiple of the screen refresh rate and the string frequency.
A CRT screen doesn't just flash on and off like a strobe but gets swept or repainted on each cycle. What that means is that different areas of the screen brighten at slightly different times and can show different phases of the string's sinusoidal motion. So you may see distortions like swimming, sperm tails, etc. Alas, it seems that (at least my) flat-panel screens have more persistence or something and don't show these effects, so enjoy them while you can!
2007-10-28 15:44:07 · answer #1 · answered by kirchwey 7 · 1⤊ 0⤋
The monitor is working as a strobe.
2007-10-28 19:13:44 · answer #2 · answered by Clueless Dick 6 · 0⤊ 0⤋