i placed a home fan in front of my face and then looked at my two Monitors. LCD, and a crt. when looking at the crt it flashed black like the fan blade was blocking the view, but when looking at the LCD it stayed the same. why is that?


Answer:
The way CRT displays is very different to LCD, hence the artefacts you’re observing.

What you’re noticing is because of the difference between progressive (LCD) vs interlaced (CRT) scan.