Join Early Retirement Today
Thread Tools Search this Thread Display Modes
Why are these denser than gold?
Old 04-07-2012, 08:24 AM   #1
Thinks s/he gets paid by the post
veremchuka's Avatar
Join Date: Oct 2010
Location: irradiated - too close to the nuclear furnace
Posts: 1,294
Why are these denser than gold?

I watched Nova on PBS this week. The show was called Hunting the Elements and very interesting.

Initially they discussed gold. It's atomic weight is 197 (protons + neutrons) it's atomic number is 79 (protons). They said only 4 elements are denser than gold - rhenium 186 and 75, osmium 190 and 76, iridium 192 and 77 and finally platinum 195 and 78.

How can these 4 be denser than gold when their atomic weight is less than gold's?

There are many elements with atomic weights above gold's, aren't they denser if a solid vs a gas?

I wonder if this comment was a mistake? Nova is a pretty good show and I would be surprised if they made a blunder like that. Anyone here know?

Here's and excellent periodic table - Dynamic Periodic Table

veremchuka is offline   Reply With Quote
Join the #1 Early Retirement and Financial Independence Forum Today - It's Totally Free!

Are you planning to be financially independent as early as possible so you can live life on your own terms? Discuss successful investing strategies, asset allocation models, tax strategies and other related topics in our online forum community. Our members range from young folks just starting their journey to financial independence, military retirees and even multimillionaires. No matter where you fit in you'll find that is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with our members, see fewer ads, upload photographs, create a retirement blog, send private messages and so much, much more!

Old 04-07-2012, 08:34 AM   #2
Thinks s/he gets paid by the post
Join Date: Aug 2004
Location: Houston
Posts: 1,406

The atomic mass or weight of Gold is 197 and its density under normal conditions is 19.3 g/cm3. The atomic mass of Uranium is 238 and its density is 19 g/cm3, slightly lower than Gold, even though its atomic mass is larger. How is that possible?

The reason is that the Gold atoms are packed in closer under normal conditions than the Uranium atoms. Most of the time, the heavier atom will result having greater density.

soupcxan is offline   Reply With Quote
Old 04-07-2012, 12:25 PM   #3
Give me a museum and I'll fill it. (Picasso)
Give me a forum ...
TromboneAl's Avatar
Join Date: Jun 2006
Posts: 11,018
The was a great show; that Pogue guy is pretty funny. I agree with Soup, there are other things that affect density.
TromboneAl is offline   Reply With Quote
Old 04-07-2012, 02:21 PM   #4
Alan's Avatar
Join Date: Jul 2005
Location: Eee Bah Gum
Posts: 18,890
As stated above, there is more to density than atomic weight. The density of water behaves in such a way to sustain life as we know it. As water cools the density increases, in line with what happens to almost every other liquid. However, once you get to about 3.9 C, as the water cools more it becomes LESS dense and floats to the top.

When a normal liquid freezes it freezes from the bottom up but water freezes from the top down (the cooler liquid is at the top). This means you get an insulating cover of ice keeping the water below liquid at extremely cold surface temperatures.
Retired in Jan, 2010 at 55
Now it's adventure before dementia
Alan is offline   Reply With Quote
Old 04-07-2012, 02:45 PM   #5
Thinks s/he gets paid by the post
veremchuka's Avatar
Join Date: Oct 2010
Location: irradiated - too close to the nuclear furnace
Posts: 1,294
Thanks, that's the answer. I assumed (!) the atomic weight was directly proportional to the density - more protons and neutrons the more dense the atom but then read below! Seems reasonable but incorrect.

The amount of empty space in the nucleolus of an atom is hard to imagine, it's mostly empty! I love this stuff but it is mind blowing.
veremchuka is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Universal Health Care - what are we waiting for? Midpack Health and Early Retirement 132 04-08-2012 10:18 PM
How frugal are you in ER? Birchwood Life after FIRE 132 04-08-2012 09:58 AM
DQOTD: Why are W-4 & 1099s required when you don't eFile? Midpack Other topics 4 04-04-2012 02:17 PM


All times are GMT -6. The time now is 01:17 AM.
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.