Why do the numbers appear to jump on an LCD clock if you chew something while looking at it?

Question

If you don't know what I mean, just try it... it seems like it works best if you're close to the clock and you're chewing something crunchy. The other things around the clock and the rest of the clock don't jump, but the numbers or other lights on the clock look like they're dancing around. Why just those?

Answer 1

The above answer misses the mark on this one.

Chewing involves flexing the jaw muscles, which you can feel with your hands swelling up the side of your face to your temples and beyond, attaching to the cranium above the temples. The flexing of theses muscles to chew sends waves of physical force through the rest of your head, including the eyes which are right by the temples. Each wave slightly compresses the material ahead of it and slightly rarefies what is behind it. These waves will ripple through the jellylike substance inside the eye and cause a brief distortion of what is being seen, by briefly changing the density (and index of refraction) of the jelly as the waves pass.

If you are a guy, try looking at one of these clocks from across the room and hum a low, low bass note. The effect can be very strong if you hit the right low note.

Answer 2

The numbers are in fact flashing very rapidly. If your eyes move rapidly at the same time, you will see a number in one position and, while it is off, your focus has moved position so when the number lights again you see it on a slightly different spot on your retina.

You can duplicate this effect by passing your hand with fingers held apart and flicking it up and down rapidly between the numbers and your eyes.

This is the principle on which a "projection clock" is based.

Answer 3

because you are bored to death and close to a coma