Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: neilep on 06/03/2006 20:43:01

Title: Dissolving Sugar !
Post by: neilep on 06/03/2006 20:43:01

Hello,

I'm Neil.

Say you dissolve a few spoonfuls of sugar in water and then boil all the water away. What will I be left with ?.. sugar ?...what form will the sugar take ?..will it be full of dry granule goodness or will it be a congealed viscous slurry of sucrose goo ?..or something else altogether ?

As a firm believer in empirical study I would do this experiment myself but I can't be bothered because I reckon someone out there knows.

Title: Re: Dissolving Sugar !
Post by: DoctorBeaver on 06/03/2006 20:53:19

I've got a couple of friends who insist on having at least 3 spoonfuls of sugar in their tea. When washing up the cups, there is always a gooey residue in the bottom; somewhat akin in constituency to rather thick quicksand. I would imagine in your experiment, you'd end up with something similar.

Title: Re: Dissolving Sugar !
Post by: sharkeyandgeorge on 06/03/2006 20:58:35

if you let the water evaporate on its own on say a windowsill you end up with a large crystal try boiling it off and you end up with caramel

"your not paranoid if they're really after you"

Title: Re: Dissolving Sugar !
Post by: daveshorts on 06/03/2006 21:01:15

If you were boiling the water away, you would eventually make toffee. What happens is that as the sugar gets more concentrated the boiling point of the mixture increases, so the temperature goes up. If it gets hot enough the sugar begins to polymerise (the small molecules stick together into longer ones) and these longer ones tangle up and make the mixture gooey and then hard.

 If you continued for long enough the sugar would get hotter and hotter until it reached its flash point and catch fire.

Title: Re: Dissolving Sugar !
Post by: ukmicky on 06/03/2006 21:02:55

quote:

---

I've got a couple of friends who insist on having at least 3 spoonfuls of sugar in their tea.

---

They add tea to their sugar how nasty is that , i much prefer to add coffee to my 3 spoons of sugar.

Michael

Title: Re: Dissolving Sugar !
Post by: DoctorBeaver on 06/03/2006 21:14:13

Dave - I did at 1st wonder whether the sugar would caramelise. I thought not, as it wouldn't get enough. I forgot to take into account the increasing boiling point. What a dumb beaver I am... D'OH [:I]

Title: Re: Dissolving Sugar !
Post by: neilep on 06/03/2006 21:27:05

Well I'm amazed that you have a couple of friends Eth !! [:)]

I too also wondered about the caramelization , so thanks Dave but what I should have said (pedant mode) was if one could boil the water away without changing the composition further of the sugar...and I reckon sharkeyandgeorge has answered that.

Thanks to you all...and Michael [;)]

Title: Re: Dissolving Sugar !
Post by: ROBERT on 15/03/2006 17:53:42

Hi Neilep,
if you are trying to grow a giant sugar crystal,
here are two sites on crystal growing:-

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi24.photobucket.com%2Falbums%2Fc23%2FSUEDONIM%2Fsugar.jpg&hash=7b6e15a8fe95b15e28bc46fc57fc4001)

"Sugar crystal floating in a saturated solution. Crystal size app. 10 mm, picture taken in polarized light "
http://www.crystalgrowing.com/recipes/sugar/sugar.htm

http://www.waynesthisandthat.com/crystals.htm#single%20crystals

Apparently large crystals can take weeks or months to grow

Title: Re: Dissolving Sugar !
Post by: neilep on 15/03/2006 18:00:00

Thanks Robert,

Ths are great links . I may actually try growing my own sugar crystal.

cheers

Title: Re: Dissolving Sugar !
Post by: ROBERT on 15/03/2006 18:11:09

These are naphthalene crystals, they form in seconds from a drop of liquid naphthalene ,
(solidifies @ 80C), put onto a glass slide:-

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi24.photobucket.com%2Falbums%2Fc23%2FSUEDONIM%2FWEEMYSTERY.jpg&hash=40c222d4ce20f0a78722706568acf07d)

The above image is approximately four times actual size,
Photographed in polarized light by yours truly.

http://en.wikipedia.org/wiki/Naphthalene

Title: Re: Dissolving Sugar !
Post by: Hadrian on 15/03/2006 20:07:12

Why did you go and post up all this stuff about crystals?

Now I going have to try it out myself…….THANKS!

What you do speaks so loudly that I cannot hear what you say.