While less dramatic, many solids will suffer from out-gassing under high vacuum. Cadmium, Zinc and Magnesium cause problems with a bit of heat and I had lots of problems with my home made vacuum depisiton chambers at below 10^-9 torr.
Graphite which makes up most of pencil lead is great once properly degassed. The wood and paint would not fair so well under extended exposure to ultra high vacuum and will degrade over a period of time.
Cellulosic materials also contain a lot of water vapor and apples will also out-gas oil and grease vapor, solvents, and organic material. Even most stainless steels will out-gas some carbon monoxide and hydrogen.
It all comes down to vapor pressure and chemical potential.
I’m still waiting to find out what it’s going to take to make this pencil explode.
To be clear, Riemann, I posted my guess about air in apples before I saw your definitive cite. I wasn’t doubting you.
Well, I don’t think anything is going to make a pencil explode. But it’s a quantitative difference, rather than a qualitative one. Wood does contain a considerable amount of air, and it would experience the same kind of forces from the pressure differential as a milk carton upon rapid decompression. But it’s much stronger than a milk carton and wouldn’t collapse while the air escaped.
Is there any kind of very soft wood with high air content (balsa?) that might be marginal? Probably not, but there’s a continuum of various other organic materials with varying air content, permeability and rigidity. As we’ve said, an apple is probably a marginal case, I don’t think we can say with confidence what would happen to an apple upon rapid decompression without experimentation. It might just shrink, it might rupture.
Sorry but the Pressure * Volume per Area per Time formula is going to lead to disappointment without serious changes to what is called a pencil.
…no worries, actually I posted the extract from that cite without seeing your comment! I had found the cite just within the edit window of my prior post, and was adding an extract in a new comment.
I have a friend who’s car had a defective vacuum release valve in the gas tank, and ended up collapsing the tank as the gas was pumped out of it.
Somewhat relevant is the Byford Dolphin decompression tank accident, in which several divers were killed. This involved an explosive decompression from equalized high pressure down to atmospheric pressure, but it’s somewhat analogous.
If an experiment aims to test rapid pressure drop, on Earth it’s much easier to set up a drop from high so standard than from standard to vacuum. This event involved a drop from 9 atmospheres to 1, a much greater difference than from 1 to zero.
If we wanted to test an apple, I think the simplest way would be to raise the pressure slowly to 2 atm, then rapidly decompress to 1 atm. That should simulate what happens to an apple on a spaceship if it ruptures to vacuum.
The problem is - that might hint what happens from 1 to 0 psi; but ignores the secondary effect, where the water in the apple will vaporise at close to 0psi at room temperature.
There are some pretty spectacular results that can be obtained by converting liquid to gas without allowing an escape mechanism. Or, if the item is flexible, it expands like a balloon.
(An offhand comment in the old movie “My Bodyguard”, kid in ceramics class…
“What are you making?”
“A hand grenade. A thick lump of clay. When the stuff is fired, the outer skin will hold in the steam until it explodes…”
Much later in the movie - teacher says “Unfortunately, one of the items in the kiln exploded and wrecked all the ceramics pieces…” )
Point taken.
From an engineering perspective, presumably the way to simulate rapid decompression to vacuum would be to enclose a small chamber at 1 atmostphere inside a much larger evacuated chamber, and open the small chamber?
Yup. Some of those spectacular results are good with salt and melted butter.
For a video entitled “Septic Vacuum Tank Truck Implosion”, that was kind of disappointingly lacking in poop.