Compression of fruit at depth

[Downing]

I think you should do the bent experiment two ways: the first with a safety stop, and the second without.

Thanks for the thread, although you ruined my plan to take a tomato with me on my next dive. I was really hoping to see it turn into a small grape.

 

[redacted]

Is that where Squash got its name?

 

[rx7diver]

Just so I know how long it should stay compressed, can you give me a few parameters, like say depth and time?

Maybe the US Navy Standard Air Tables can help here. Take the tomato on a 6 atm (= 6 * 33 = 200 fsw approx), deep air dive. So pressurize your pot and its contents to 6 * 14.7 = 90 psig approx. The NDL for a 200 fsw dive is LT 5 min, so keep the pot and its contents pressurized for 10 min, say. Then release the pressure quickly, say, at a rate faster than (60 fsw/min) * (14.7 psi / 33 fsw) = 30 psi/min approx.

I'm guessing the water will bubble, and the tomato, being mostly water, will bubble and possibly burst (i.e., "explode").

Think this will work?

 

[Zeke XA3]

Your assuming that Tomato tissue has a similar M value to a human body tissue, more specificly the M value of the controlling compartment for that depth (pressure) . (Assuming exceeding the m value guarantees bubble formation).

Since the fruit is now dead, gas exchange is slower? Since there is no movement inside the tomato i would guess that the pp of N2 or any other gas in the tomato would not increase very fast . Also im pretty sure the skin is pretty much impermeable requiring organic action to transfer molecules through it so i doubt any N2 or other gas would transfer from the water to the fruit.

But thats just my theory, still needs to be backed up by scientific experiment

 

[rx7diver]

Zeke_XA3,

Good points! Maybe a subsequent trial should use a higher pressure and a longer bottom time. I'm thinking that if the bottom time is long enough, the oxygen which has become dissolved in the water under increased pressure will transfer from outside to inside the tomato.

 

[Zeke XA3]

Is it Boyle??? *Looks at stack of TDI book out of arms reach*...

Anyway but if left long enough, and as long as the cell membranes are equally permeable to all gases,the partial pressures on any of the gases in the solution will try and enter the cells of the fruit to become equal.

But yes you will want to supersaturate the cells with as much gas as possible for the most dramatic effect!

 

[Ed Palma]

Okay Zeke and Rx7, experiment run and you guys can hash out the science of it.

Parameters:

Took a tomato to 50 meters for 15 minutes. There was note of a slight leak so by the time the expt ended, depth was at 42 meters.

Notes:

1. Upon compression, the tomato lost its buoyancy and sank to the bottom.
2. The tomato started to expand (as seen on video) causing cracks on the skin of the tomato.
3. Upon decompression, the skin started to delaminate and the cracks deepened. small bubbles were noted to come out from the tomato. Tomato did not explode.

Tomato at 5 minutes:

Tomato at 10 minutes:

Tomato at 15 minutes:

End result:

Remarks:

1. It is possible that the expansion was caused by the slight decompression induced by the slow leak. With a stable system, maybe there will be less expansion (I'm running low on tomatoes, so further testing will have to wait)
2. Bubbles from the tomato on decompression indicate that there was a degree of gas diffusion into the fruit. Of course it would've been better if I was running a control tomato immersed in water without the variable of the pressure.
3. I would imagine that given enough time and pressure, fruit could be made to explode. I remember reading how Woodshole Oceanographic would have difficulty retrieving specimens of deep sea animals without it disintegrating. Not having this facility, I nominate we elevate this to the mythbusters...

Video to follow. I'm just increasing its speed so you can see the expansion.

 

[Zeke XA3]

Strange the skin cracked as upon de-compression it should have only expanded to starting size...unequal expansion maybe?

Just to note that tomatoes do have air space so the bubbles may have been from air already inside. also maybe as to why it sank upon pressurisation (compression of said air?).

As for your third point this is also due to the fact that country to some entry level teaching water is compressible. As you bring a sample up from depth it expands , this lack of pressure causes the structure of many sea creatures to be unable to support their own weight as well as rapid decompression causing DCS. And don't get me started on how we have to correct for temperature measurements due to expanding water lowering the temperature!!!

Try a kiwi/peach? Im thinking a fruit that does not have a protective "skin" that will enable better gas exchange?

 

[Ed Palma]

Here's the video. I sped up the expansion portion, but if you grab the slider, you can see the effect much more by dragging it faster.

 

[Sas]

Was the water warm? I guess so when you raised the pressure. Just looks like it has started cooking a bit and then been cooled. For some dishes where I need peeled tomatoes I make I boil tomatoes for a few minutes and then stick into cold water, and they look exactly like that (makes the skin easy to get off).