Question possibly to do with atmospheric pressure (but possibly not)

In summary, the speaker has a question about their watch getting steamed up on seemingly random days. They initially thought it was due to changes in atmospheric pressure, but upon further investigation, they believe it may be due to temperature differences between the watch and its surroundings. They have tried various methods to remove the condensation, but it seems to be a day-to-day occurrence. They plan on conducting an experiment by putting the watch in the fridge to see if it has any effect.
  • #1
Turtle492
20
0
I have a question about my watch which has been bugging me for a little while, and I was wondering if anyone could enlighten me as to the physics behind it.

One day a while back I went out for a run in the rain and some water got into my watch, behind the glass. I only noticed because it had condensed on the glass and was making the watch face blurry. I thought I'd ruined the watch but the next day, the water droplets had vanished, so I thought they'd managed to find their way out of the watch, but no - some time later, they reappeared again. And now, every now and then the glass gets steamed up (but only in the middle), on seemingly random days. Temperature doesn't seem to have much impact (it's steamed up today and it's about 15 degrees, but it also steamed up last week when it was really hot), so I was wondering if it might be something to do with changes in atmospheric pressure?

I might be barking up completely the wrong tree, but if anyone can explain it to me that would be great.
Thanks!
 
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  • #2
I've seen this a bunch of times, from watches to my phone camera lens to my "waterproof" camera lens.

I don't know for sure what it is, but would guess it's not atmospheric pressure, but simply temperature differences between the watch and the outside air. Just like breathing hot moist air on your watch causes the water in the air to briefly condense when it hits the colder surface of the watch glass, I think if the interior of your watch is hot compared to the glass surface, the hot moist air inside the watch condenses on the inside surface of the watch, and since it's enclosed, with no airflow, and a perpetually moist atmosphere, it is very difficult for the moisture to evaporate again.

When it steamed up today (at 15 degrees) the watch was probably taken from a warmer climate (say, indoors) to outside, which caused it to fog, and if it steamed up on a hot day... I don't know, but did you have the watch in an even hotter environment first, like, say, in hot car?

Next time it steams up on a cold day you could just try mashing your thumb on the glass for half a minute to warm it up and see if it clears it up (just for the short term). It worked on my camera last winter. Also, you can throw your watch in the freezer overnight and then wear it outdoors on a cold day and see if that helps. Not very practical, but maybe an interesting experiment.
 
  • #3
kjl said:
When it steamed up today (at 15 degrees) the watch was probably taken from a warmer climate (say, indoors) to outside, which caused it to fog, and if it steamed up on a hot day... I don't know, but did you have the watch in an even hotter environment first, like, say, in hot car?

Next time it steams up on a cold day you could just try mashing your thumb on the glass for half a minute to warm it up and see if it clears it up (just for the short term). It worked on my camera last winter. Also, you can throw your watch in the freezer overnight and then wear it outdoors on a cold day and see if that helps. Not very practical, but maybe an interesting experiment.

Thanks for the reply, although I'm not sure it's temperature related. I could understand it if the condensation was just caused by going from a hot place to a cold place, but this seems to a be a day-to-day thing. I wake up in the morning and either it's steamed up or it isn't, and it stays that way for the rest of the day, as far as I've noticed. Mostly it's not steamed up, just occasionally it is.

I've tried rubbing on it with my finger but it doesn't appear to make much difference. Next time it isn't fogged I might try throwing it in the fridge and see if that does anything... Like you said, would make an interesting experiment.
 

1. What is atmospheric pressure?

Atmospheric pressure is the force per unit area exerted by the weight of the Earth's atmosphere. It is measured in units of pressure such as millibars or inches of mercury and is affected by factors such as altitude and weather conditions.

2. How is atmospheric pressure measured?

Atmospheric pressure is typically measured using a device called a barometer. There are two main types of barometers: mercury barometers, which use the height of a column of mercury to determine pressure, and aneroid barometers, which use a flexible metal chamber to measure pressure changes.

3. How does atmospheric pressure affect the weather?

Changes in atmospheric pressure can indicate changes in weather conditions. High pressure systems are usually associated with clear and dry weather, while low pressure systems often bring cloudy and rainy weather. Changes in atmospheric pressure can also impact wind patterns and storm development.

4. What is the relationship between atmospheric pressure and altitude?

As altitude increases, atmospheric pressure decreases. This is because there is less air above you to exert pressure. At sea level, atmospheric pressure is typically around 14.7 pounds per square inch (psi), while at the top of Mount Everest, it is only around 4.6 psi.

5. How does atmospheric pressure impact human health?

Changes in atmospheric pressure can affect human health, particularly for individuals with respiratory conditions. High pressure can make it more difficult to breathe, while low pressure can cause headaches and joint pain. Extreme changes in atmospheric pressure, such as those during a hurricane, can also be dangerous for humans.

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