Science question : Does the viscosity......

Something must be happening with the water as it warms up as it becomes easier to wash things up!

Stupid I know but I do work in catering and warm water is what is needed to clean things. Yes detergent helps a great deal but if you only had water to wash up, you want it warm.

Heres a thing thing though. It dosn't get easier the hotter the water. If it gets over hand bearable hot then it become less effective at cleaning stuff.

I have no idea why this is but I know its true because I handle the stuff every day.

 

I used to have a Chemistry teacher who used to say that things work better when heated (as he stood at the front of the class flexing his cane)(I'm not kidding). Another of his favourite sayings was that round bottoms heat better than flat ones Perve!

 

and it made you the man you are today

 

As the temperature goes up, Gary, so does water's ability to dissolve things. In your case, the greases and oils present in cooking become softer and will come off more easily.

The observation that it doesn't get easier is probably a reflection of the fact that there will be an optimum solubility for any given solvent-solute pair at any given temperature. This is overcome by your detergent. All detergents are surfactants, molecules with one end strongly attracted to water, the other strongly repelled by it. The repelled bit will stick to anything before it will stick to water, and as those greases and oils are similar in chemical constitution, it goes for them. And the bit that is attracted to water does the rest, yanking the whole thing off the plate into the wash water.

You can make detergents that are effective in freezing cold water, but you wouldn't want your bare hand anywhere near them! They're even more ferocious than dishwashing machine detergents (which is saying something).

 

Only if those 'things' are solid. Water's ability to dissolve gases decreases with increasing temperature

 

Thanks, Chris, quite right, I stand corrected.

 

Speaking of hard water...



Given that this is about what "Titanic" hit and that glacial ice, formed under pressure, has a hardness approaching that of metamorphic rock, you begin to see what it was no contest - it was like ramming the Isle of Wight.

 

IIRC the problem with the Titanic is that they didn't ram the iceberg.
They tried to steer around it and were ripped open like a tin can.

The Titanic was designed to hit icebergs head on and stay afloat.
I guess the Captain figured he new better and didn't want to subject the passengers to a sudden stop.

I also heard that the steel used to build the Titanic suffered from something we now know as the brittle-ductile transition. Basically as the steel gets colder it becomes more brittle and less ductile (it breaks instead of bending) and it was pretty cold that night with icebergs floating around.

 

Re: Speaking of hard water...

Sorry Tones, that photo's an urban legend: real story

 

Thanks, Gambit, but a nice story nevertheless! And it does give you an idea as to what's under the surface. The figure "nine-tenths sumberged" tends to be an abstraction, until you see something like this.

 

I don't think it was ripped open, Warren, I think that, as per your last paragraph, the steel probably shattered. The steel of "Titanic" was almost a plate iron, and with the sea extremely cold on that very calm, clear night (probably close to the sea water freezing temperature of around -3°C), it would have been much more brittle than usual. The proof or otherwise is buried in silt two miles down on the floor of the Atlantic.

Capt. Smith wasn't on the bridge when lookout Fleet gave the fatal alarm (it was a moonless night, so the iceberg only became visible when "Titanic" was almost on top of it). The First Officer, who had the bridge, reacted instinctively, putting the helm hard over, a move that accorded with normal practice, but that sank the ship. Had the ship struck head-on, it would have survived and Capt. Smith's last voyage (he was White Star's senior captain and due to retire) would have had egg on its face, instead of wiping out the population of a small town.

 

Yeah the picture might not be real but it gives you a good idea.

The scary thing with icebergs is that as they melt they tend to flip.
I would hate to be close by when a big one flips over
Usually when they flip over the protruding piece of ice is transparent. Imagine trying to spot that on a still night with no waves breaking against it.

 

Tones, the plates may well have shattered as you said but remember that the rivets were made out of the same steel. The rivets would have given way very easily.

In the end it was probably a bit of both.

 

Yes, indeed. Unless deep-sea submersibles become much more versatile and can (or could be bothered to) excavate the large quantity of silt that covers the crack/tear/whatever, I don't think anyone will ever know.

I come from Belfast and my great-grandfather helped build it, so I've always had this fascination for it.

 

Re: Re: Speaking of hard water...

Really? That is interesting. I saw this picture used in a lecture by a respected academic recently - I'll have to e-mail him your link .

 

Re: Re: Speaking of hard water...

I think that rather nicely illustrates the "controversy" over Michael Moore's books & films (see the "Bowling for Columbine" thread).

The photo isn't real, it's a composite and technically it's a "lie" but what's it's showing is real, it just couldn't be captured in a single photo.

IMO what Michael Moore says is true and not misleading or distorting even if he has used "tricks" to show things that would otherwise be difficult to show.

Michael.

 

Snopes is a great site for dispelling internet myths - 99% of the stuff you get on E-mails is bullshit, so a quick search on there ofter reveals the truth It's also quite intersting for general reading too

 

But Michael Moore lies,

Like this,

Full transcript here

Paul