Science and Technology Quiz 3

[SS-18 ICBM]

I'd be really impressed if someone could make glass at home with ordinary appliances and household products.

 

[GoodGame]

What is a superheated and supercooled fluid? And how would one make examples of both at home?

Superheated: A liquid heated to/beyond its heat of vaporization, but pressurized to avoid a phase shift. Guess an obvious example would be liquefying sugar in a stove pot with lid.

 

[Mise]

Put an unopened bottle of water into the microwave? It can't boil cos it's sealed, the plastic won't melt cos it's only at ~100 C, but the water will continue to absorb the microwaves and get hotter.

Conversely, fill a bottle right to the top and put it in the freezer? The water can't freeze because ice takes up more volume than water, and the bottle won't deform to allow it?

 

[SS-18 ICBM]

Put an unopened bottle of water into the microwave? It can't boil cos it's sealed, the plastic won't melt cos it's only at ~100 C, but the water will continue to absorb the microwaves and get hotter.

Conversely, fill a bottle right to the top and put it in the freezer? The water can't freeze because ice takes up more volume than water, and the bottle won't deform to allow it?

Right on the first one, really close on the second one. There's just one thing wrong with what you're doing.

 

[Falcon02]

When I hear Superheated liquid I think of microwaved water in a smooth container (ie. glass jar).

The water becomes hotter then it's actual boiling temp ie. > 212 F (100 C). However, steam is unable to form on the sides of the container so it remains in a liquid state.

As soon as the liquid is disturbed the superheated liquid boils over.


Supercooled liquid makes me think of cooled salt water. With the salt in the water, the salt becomes ionized and prevents the water from freezing. The Water can then be cooled below freezing 32 F (0 C) and it will not freeze because the salt prevents the water from forming ice crystals.

 

[Mise]

Umm, hmm, first put slightly more than enough water in the fridge (fridges are usually at about 4 degrees, which is the temperature that water is most dense), then when the water has cooled to 4 degrees, fill the bottle right to the top, close the lid, and put it in the freezer. That way the water is sure to be more dense than the ice, so won't freeze at all, even though it's getting colder.

 

[SS-18 ICBM]

No, not quite yet. It is actually much simpler than what you're describing. It all depends on the type of water you use.

Hmm, looks like multiple people will have to share credit for answering this multi-part question.

 

[uppi]

Supercooled water is water with a temperature below its freezing point that lacks seeds to form ice crystals. For example pure distilled water can be supercooled as it lacks "dirt" to seed the crystals.

Pure water can be cooled to a temperature quite below the freezing point. But once a tiny crystal is formed, the rest of the water will freeze almost at once.

Pure water can also be superheated, following the same principle. If you put pure water into the microwave and heat it, it can become superheated and explode once you put something in there.

 

[Brighteye]

You want the water distilled first?

 

[Mise]

I have no idea what could be simpler than filling a bottle with cold water and putting it in the freezer

 

[SS-18 ICBM]

Oh there is...

 

[GoodGame]

Oh there is...

Putting frozen ice cubes in 1 degree Celsius water????

 

[SS-18 ICBM]

That would cause the water to freeze normally. Come on guys, the process here is simple enough to put in a two-step YouTube video.

 

[GoodGame]

That would cause the water to freeze normally. Come on guys, the process here is simple enough to put in a two-step YouTube video.

That has me thinking endothermic reaction utilizing some common chemical catalyst, like a reverse mentos. Can't think of one though.

 

[Kal'thzar]

No, not quite yet. It is actually much simpler than what you're describing. It all depends on the type of water you use.

Hmm, looks like multiple people will have to share credit for answering this multi-part question.

Types of water?!? I mean I have tap water annnnnd thats about it :/

Anyway uppi seems to have it with pure water, just go buy some bottled water 'free from impurities' and stick it in the freezer

 

[SS-18 ICBM]

Anyway uppi seems to have it with pure water, just go buy some bottled water 'free from impurities' and stick it in the freezer

YES! It's that simple! I can't believe you guys didn't get it.


Link to video.

Guess any of you guys who answered can get it. You can argue who contributed the best answer, if you want. Collaboration on a multi-part question after all...

 

[thetrooper]

Post #248 seems to be the most revealing though...

 

[ainwood]

Supercooled water is water below the freezing point that has not formed a crystalline solid. Superheated water is water heated above the boiling point at that pressure that has not vaporised into steam. The points about not having a surface to nucleate bubbles on (boiling) or nucleate crystals on (freezing) is pretty key to both processes.

To correct a couple of points: You don't get super-heated water by changing the pressure; that merely changes the boiling point.
Bottled water won't necessarily do it, because bottled water typically contains a lot of dissolved solids (minerals).

 

[Brighteye]

Guess any of you guys who answered can get it. You can argue who contributed the best answer, if you want. Collaboration on a multi-part question after all...

And this is why scientists don't collaborate. Who gets the reward?

 

[GoodGame]

And this is why scientists don't collaborate. Who gets the reward?

Scientists don't collaborate??????

I vote Ainwood has the best basic definitions.