why doesnt condensation form on light bulbs?

Answer 1

condensation forms when the temperature of air drops below the dew point of the air. if the light bulb is the same temperature as the surrounding air and the air is not saturated, then no condensation occurs. if the temperature of the light bulb is less than the dew point temp of the air, then water will condense on the bulb.

try this experiment.. next time you have a hot humid day, put a light bulb in a freezer for a few minutes then take it outside. condensate will most likely form.

at the same time, when light bulbs are on, they usually have a temperature hotter than the surrounding air. and therefore have a temp above the dew point and no condensation forms...

relationship between humidity, dew point and dry bulb temp is found in a "psychrometric chart"

here's a ref..
http://www.sp.uconn.edu/~mdarre/NE-127/NewFiles/psychrometric_inset.html

for example for a particular amount of water in air (on right lbs moisture / lb air) as temp drops (bottom - dry bulb temp) humidity increases to 100% at which point condensation occurs.

for a nice summer day of say 80 F and 60% humidity, lbs water/lb air = 0.014 and dew point would be around 66 F. so water would condense on any bulb less than 66 F

Answer 2

If you bring in a light bulb from the outside when its really cold outside, moisture in the air of the house will then form condensation on the bulb.
While in the house or outside in the cold, condensation won't form because the bulb is the same temperature as its surroundings.
When the bulb is lit, it is too hot to allow condensation anyway.

Answer 3

Condensation occurs when there is a significant temperature difference on the surface of the object (lower temperature) where water vapor can touch, cool down, and collect.

Light bulbs are very thin glass with very small heat mass. It is also vacuum inside. It quickly equalize in temperature as surrounding. With it being the same temperature, water vapor that comes in contact with the surface does not cool down to form condensation.

By the way, I am assuming the light bulb is OFF.

Answer 4

I am not a physics person but if I am not mistaken condensation is the process where water vapor (a gas) turns into a liquid (condensation). In order to go from a gas phase to a liquid phase a loss of energy is required. Light bulbs are pretty hot (at least the incandescent ones are). I don't think water vapor (a gas) will cool down enough when coming into contact with a hot light bulb to change into a condensate (a liquid).

Otherwise, beats me!

Answer 5

Of course, if the light bulb is burning, the heat from
it would prevent it from forming. However, even so,
for condestation to form, the enviornmental humidity and temperature of the object must be incompatible in the
first place.

The light bulb, generally is not located in such a an
environment for condensation to occur. Both temperature
and humidity are stable. However, were it in an environment
for such to occur, the make up of the light bulb would prevent condensation.

It contains within it billions of tiny reflectors. These refelectors, even if the light bulb is not burning, reflect what little light (light that you and I cannot even see) to such a degree that it repels or dries moisture on contact.

Answer 6

Condensation forms on something when it is cooler than the air and it causes the air to not be able to hold the same percentage of water.

The warmer the air is the more water it can hold. Water in air is called humidity. When the air gets cooler it cannot hold the same water so it drops it as rain.

But when the air is cooled close to something like glass of ice water, the water in the air sticks to the class. This is called condensation.

Answer 7

It does......................

as long as the bulb is not on....

when you turn on the bulb it heats up...evaporating the condensation..

If the glass is cooler than the surrounding air, water droplets will form on the glass...

Answer 8

well, it only doesn't form when the lightbulb is on, the glass heats up, evaporating the water. but when the lightbulb is off, condensation can form on it, if it is cool enough and there is enough moisture in the room. why do you want to know, anyways?

Answer 9

ON? I would think the heat dissipates the moisture quickly..if you mean inside...it's because it's vacuumed sealed...not an expert just using logic.