Physics law

Nothing earth shuttering, just wanted to share.

I am in Florida, Everglades National Park. Pulled the camera from a cold car and attached the CPL filter. In the middle of the day, 86 degrees F (30 C for our friends outside of the U.S.) I wanted to remove it, but it stuck on, no matter how much I tried. Spent another hour in the car on the way back (72 F), and the filter got off effortlessly.

You just cannot beat physics laws!

Nice,

At least you know it was made of metal for sure now.

Very best,

Wouldn't that be thermodynamics, not physics?

Jimmer411 wrote in post #17349754
Wouldn't that be thermodynamics, not physics?

If I remember correctly, which is very hard - I had a TD class in college in 1970 and never used it since, the TD is about heat transfer. I am taking here about material properties, i.e., material expansion with temperature.

Actually, I was taking about bird photography in Everglades...

I thought you were going to tell us how it fogged up and became useless

You likely could have overcome your physics (or thermodynamics) problem with a rubber band. When this happens to me I wrap one around the filter. 95% of the time it provides enough extra grip to get the filter off.

Funny how that works. Thinking about how many siezed things I've taken an acetylene torch to and have them come unsiezed. Maybe pack a torch in your kit for next time the filter siezes

Thermodynamics is a subset of Physics dealing with heat energy, including its effects on solids. Either can be used in this case.

Tyguy wrote in post #17358370
Funny how that works. Thinking about how many siezed things I've taken an acetylene torch to and have them come unsiezed. Maybe pack a torch in your kit for next time the filter siezes

I'm pretty sure that would void any remaining warranty!!

Jimmer411 wrote in post #17349754
Wouldn't that be thermodynamics, not physics?

It would fall under the coefficient of linear thermal expansion. So I'm leaning toward thermodynamics.

but if it is to do with material properties, it would have to do with heat transfer rates also to enable expansion of some parts faster than others, first law of thermodynamics....

Thermodynamics is a branch of physics, so saying "thermodynamics, not physics," is akin to saying, "no, that's a bird, not a vertebrate."

Harm wrote in post #17359046
but if it is to do with material properties, it would have to do with heat transfer rates also to enable expansion of some parts faster than others, first law of thermodynamics....

Thermodynamics is generally the study of energy and entropy. Most common topics would be the 1st and 2nd law and then general application to power and refrigeration cycles.

Conduction is one form of heat transfer, and heat transfer is usually taught as a standalone engineering subject covering conduction, convection and radiation.

I'd suggest the experience of the OP is most likely related to the field of materials science (differential coefficients of thermal expansion). It could be related to heat transfer (differential heating of different parts of the assembly), or both.

After reading all the replies I do believe this information may very well help me to remove the lid from the jelly jar the next time it is stuck.

Could you have carried any of the parts in your pocket and assembled them on site?