Gallium picture

Date 08-16-2008 06:58 Edited 08-16-2008 07:14

This is a picture of Gallium atomic number 31 melting point 86F
Like mercury although its considered largly non toxic
will shatter easily like glass when frozen
Forgive me for rambling,
Once this metal has melted It takes a certain amount of energy to refreeze, that is it will cool itself kind of like an aerosol can I think, but I may be wrong I'm no physicist. This means it takes extra enery to re freeze. More so than when it melted. My confusion lies with my high school chemistry - There is no cold only abscence of heat.
Any comments
I will try and edit this but I don think its gonna happen so take a shot at it.
Oh yeah one more thing to add: I read in a lincoln metallurgy book that the melting point and freezing point of a metal are the same
Darnit, i think I went too far:)

Attachment: gallium.jpg (29k)

By DaveBoyer (*****)

Date 08-17-2008 04:45

Melting and freezing points are the same for an element or a eutectic solution. When You have a non-eutectic mixture of materials melting and freezing take place over a range of temperatures. This is the difference between an ice cube and a Slurpy.

A great ammount of heat must be added or removed to change from one phase to another. Using water as an example, to get from water at 32F to ice at 32F a lot of heat must be removed, but the temperature is the same. To go from water at 212F to steam at 212F a lot of heat must be added, but the temperature stays the same.

By and4rik (**)

Date 08-17-2008 05:54 Edited 08-17-2008 06:47

So this is why beer bottles crack in the freezer.
I don't like this picture btw but it was the only one I could find. I was hoping for one that would show lamillar shattering in the glass.

Attachment: frozenbudbeer.jpg (0B)

By sbcmweb (****)

Date 09-05-2008 02:25

A waste of a good beer. Darn those laws of physics! S.W.

By RANDER

Date 09-05-2008 02:28

Yeah but when that happens you usually had 15 good ones already

By sbcmweb (****)

Date 09-05-2008 02:53

True....So true. S.W.

By Stephan (***)

Date 08-18-2008 10:54

Dave,

that was a most excellent explanation*!

It's a pity that there is no "rating" possible with the "Metallurgy" section.

I would have given you immediately 3 diamonds for that!

Best regards,
Stephan

* I wish I had the ability to hit the nail that precisely on the head as you are able to, Dave!

By DaveBoyer (*****)

Date 08-19-2008 05:40

Thanks Stephan.

By and4rik (**)

Date 08-19-2008 06:12

Appreciate your input Dave. This is a picture I have been fascinated with for a long time, even before welding. I'ts great to have new light shed on this exciting topic.

By sbcmweb (****)

Date 09-05-2008 02:26

Dude, I'm no metallurgist, but it looks like Silver Surfer Poop. Plain as day. S.W.