how come if you spit on a hot light bulb it shatters?

Answer 1

The glass is very thin and the bulb is very hot. The sudden change in temperature causes the galss to shatter because glass is not flexible and cannot change that fast. Remember, heat causes expansion and cold causes shrinkage and by doing this, you have caused a small area of shrinkage on the surface of the bulb.

Answer 2

Glass iis like any other tinsile material.. at high temperature, a sudden cooling in any spot, small or big, will result in shattering.

Why?

Spit is much cooler than the surface of the glass. The glass itself expands when hot... and a quick cool spot once spit upon.. that spot shrinks too quickly. It forms a crack, and the vacuum inside the bulb (there is no air inside a bulb) implodes, then the air claps together in that little spot, and explodes the shattered glass outwards.

Answer 3

Rapid cooling of the glass bulb (only in the area touched by the liquid) causes a very, very rapid contraction. Since the contraction only occurs where the glass has been "moistened", stress builds up at the interface between the relatively cooler "moist" glass and the hot "dry" glass. Since the stress builds very rapidly, and the shape of the bulb is relatively "fixed", the bulb shatters. BOOM!

Answer 4

You know I mis-read your question but was facinated so I went and **** on a light bulb. It wasn't until after I cinged my butt hairs that I came back and ready that you had said "sit". In my experiment it didn't shatter but it did bubble a bit and it's quite foul in here.

Answer 5

Because the glass is hot, and the spit cools it down very quickly and unevenly. The hot glass expands, the cooler glass contracts, and BANG!

Answer 6

Oh good idea, now I want to try it! Maybe because the sudden drop in temperature causes the bulb to implode on itself.