[RD] Exploring Japan

[warpus]

 

[warpus]

The White Pond Hell

After visiting the first 2 hells I had to jump on a bus to get to the remaining 6. Next on my list was the White Pond hell, which features a pond of boiling milky water.

 

[warpus]

This video of the Sea Hell looks cool in slo mo. I will post a slo-mo version of this later, but for now you can change the playback speed on youtube down to 0.5 if you want. 0.25 looks a bit too choppy. Regular speed is of course fine as well

 

[amadeus]

Did you visit any onsens while here? I love staying at the old resorts—built in the ‘70s in particular—they’re very relaxing and have a lot of great food. Also, they’re cheap! I went on vacation (modest means here!) for less than $200.

If anyone here is ever in Japan, I sincerely recommend checking out Toba in Mie Prefecture for a vacation! It’s one of my favorite spots and anyone seeking the “authentic” Japanese experience should go!

One note: Japan’s like any other country. The “authentic” experience you get might not be what you expected!

I personally love the old resorts. Not just the price, but the hospitality and quality of service are really unmatched to me. Just my opinion though!

 

[warpus]

I made use of 2 onsen on my trip, both in Beppu. I wrote about my first experience, it should be somewhere on the last page. The second was even more interesting and is coming up later

 

[amadeus]

The rotenburo, or “open-air baths” are my favorite. It might be cold outside, but little is more relaxing than sitting in one overlooking a quiet green hill or seaside.

It always makes me annoyed that I’m stuck in the concrete “paradise” of Osaka.

 

[warpus]

The second one I tried was in part an open air one, actually. It was a cool experience. No pun intended at all, it was actually quite warm in the mud/water..

 

[warpus]

The Devil's Mountain Hell

 

[warpus]

The Devil's Mountain Hell (continued)

Also known as the Crocodile Hell

 

[warpus]

The Cooking Pot Hell

This hell features several boiling ponds, there is a foot bath, and an eating area where you can try foods that have been steamed over the hot springs. You can even drink hot spring water or inhale the hot spring steam

 

[warpus]

The Cooking Pot hell seemed to be a bit more touristy than the other hells I visited up until that point. The tour guides I saw were a bit more vocal and interactive than at the other hells. The dining (and foot bath) area also attracted people to stick around, whereas the other hells were to some extent more of an "in and out" sort of proposition. To be fair it could have been a matter of timing, but this hell also had several different ponds for you to check out.

In both videos the guide is blowing cigarette ash at the geyser. Or holding an unlit cigarette and blowing on that.. I'm not quite sure. I was not in this tour group at all, I just tagged along temporarily to see him do his thing. I can not understand anything he is saying (although I can for sure read the tone), but I believe he is triggering some chemical process.

 

[warpus]

The Sea Hell

 

[Birdjaguar]

Do you know the temperatures of the water in the Hell ponds?

 

[warpus]

Do you know the temperatures of the water in the Hell ponds?

It seems that the Blood Pond Hell is the coolest of them, the water there reaching temperatures of 78 degrees celsius. The Tornado Hell is supposed to be the hottest, with water reaching temperatures as high as 150 degrees celsius.
​

 

[H4run]

The white milky one is just amazing, it is not just the picture, even the video is amazing. Unlike the other that emanates dark nuance, that one I found it to be chilling and look peaceful. Like a pond above the cloud. Amazing post.

 

[tjs282]

water reaching temperatures as high as 150 degrees celsius

How many miles deep do they have to sink the thermometer to register that temperature?!?

 

[warpus]

I assume they're reporting the temperature of the steam. I've done some cursory reading on steam.. and.. it seems that this could be a case of superheated steam? I'm not really sure. Steam usually only reaches 100C, based on what I'm reading. However, it is somehow possible to superheat it, so that's probably what is being reported here. You'd think it can't be the water they're measuring the temperature of, because at that temperature it wouldn't be liquid anymore.

 

[tjs282]

I assume they're reporting the temperature of the steam. I've done some cursory reading on steam.. and.. it seems that this could be a case of superheated steam? I'm not really sure. Steam usually only reaches 100C, based on what I'm reading. However, it is somehow possible to superheat it, so that's probably what is being reported here. You'd think it can't be the water they're measuring the temperature of, because at that temperature it wouldn't be liquid anymore.

Steam-temperatures are by definition (much) higher than 100°C — and water can stay liquid at temperatures above 100°C as well, if it's put under additional pressure: that's at least partly how pressure cookers work.

But that's also kind of why I asked, I was wondering how much pressure would be needed to develop a (liquid) water-temperature of 150°C.

Spoiler Info-dumping :

Geysers usually consist of a reservoir-chamber close to a geothermal source, plus a (long) narrow tube above that reservoir which reaches the surface. Water seeps into the reservoir and tube from the surrounding rock, and if the rate of inflow exceeds the rate of boil-off, then both chamber and tube will eventually fill up. If the water-column's long enough, then once the tube is full, the static pressure above the reservoir — like in a pressure-cooker or autoclave — will prevent the (liquid) contents of the reservoir from fully vaporising at as 'low' a temperature as 100°C. So it is actually the water (in the reservoir) that would be superheated, and just how superheated would be directly proportional to the pressure of the water-column above it.

At 'periodic' geysers like Old Faithful, eventually enough superheated steam becomes trapped in the chamber that its pressure equals the static-pressure of the water column, and it starts pushing the superheated water up and out (like in a stovetop espresso-maker). When sufficient water has been evacuated (= decreasing the static pressure), any superheated water still remaining in the chamber also flashes to steam, and blows out the rest.

The tube doesn't need to be miles long, though, that was just me being facetious. As little as 10m/ 33ft of water-depth adds 1 atmosphere (101325 Pa) of pressure on the reservoir (e.g. a shaft 10 m long would exert 2 ata = 202650 Pa).

But I could/should probably have just calculated it.

Since P1/T1 = P2/T2 (Guy-Lussac's law), then T2(P1/T1) = P2. So where

P1 = 101325 Pa (surface pressure)
T1 = 100°C (373K, water-boiling temp. at surface pressure)
T2 = 150°C (423K, water-temp. at the bottom of the shaft/pond?)

...then P2 (pressure at the bottom of the shaft) = 423(101325/373) = 114907 Pa

114907 – 101325 = 13582 Pa, which would imply a (water-filled) shaft (or pond!) a bit under 1.5 m long/deep. Which, wow, is much less than I would have expected. Can that be right, or (where) have I miscalculated...?

(That said, though, the Wikipedia article I linked at the top does say that pressure-cookers can reach 120°C with only ~10000 Pa additional pressure...)

 

[JohannaK]

Yeah, that makes sense. I was a bit puzzled how we're supposed to have steam at 78°, but it's been a few years since my last physics class.

 

[warpus]

That's a bit fascinating, thanks for writing that all up @tjs282. Shows you how much I know about steam (but it's always fun to learn)