I have applications where this sort of conversion is useful -- when dealing with absorption of charged particle or photon radiation in material, it's useful to convert from physical density to areal density and absorption lengths. I rather doubt that a 14-year-old is really interested in designing electron or gamma shielding, but I could be wrong :-)

What about calculating the energy of spinning disks of different sizes and equal surface density? I know it's a lame example, but it is at least something I can think of... but not quite calculate :)

They *are teaching things closer to calculus at earlier ages for advanced classes these days, which is why i didn't simply discount it. My 12 year old nephew has already started on elementary calc and trig in his Math classes. We barely scraped the edges of trig in 7th grade and didn't sniff at calc's rear end until 10th or 11th.. I suppose I remember my dad saying as much about the difference between what we (me and sibling's generation) were taught when I was a kid and what they were exposed to when he was one. idk.

_{You're probably right, but I was feeling less persnickety than I usually am and decided to err on the side left side of the probability curve for a change.}

With a length and lots of zeros. Beyond that, re-read the chapter you just covered in class.

If this isn't a homework problem, tell us about your project (just edit the question and add some text) so we can understand why you need to convert from volume to surface density. Then we might be able to help you find the data you need.

## Discussions

Best Answer 9 years ago

The others have it correct but as your keyword is density, I presume you mean kg/m^3 (cubed)...

in which case, there are 100x100x100 cm^3 in 1m^3. *one million

There are 1000 grams in one kilogram.

Convert:

Say something is 1 gram per cm cubed (water).

multiply by 1 million to get the new volume

1 million grams per meter cubed

now divide by 1000 to get kilograms.

1000kg per meter cubed.

Answer 9 years ago

**same applies to any shape and units of measure, so long as they're mass and volume.

just convert the number of cubic whatevers to the new number of cubic whatevers, and the old mass to the new mass and use to divide or multiply.

9 years ago

i have the algodoo program i was trying to make a periodic table of element densitys

9 years ago

Well technically, you don't. The units don't balance.

I suppose you could use the idea of substitution, but that's as far as I'll answer what *appears to be homework.

Answer 9 years ago

I have applications where this sort of conversion is useful -- when dealing with absorption of charged particle or photon radiation in material, it's useful to convert from physical density to areal density and absorption lengths. I rather doubt that a 14-year-old is really interested in designing electron or gamma shielding, but I could be wrong :-)

Answer 9 years ago

What about calculating the energy of spinning disks of different sizes and equal surface density? I know it's a lame example, but it is at least something I can think of... but not quite calculate :)

Answer 9 years ago

They *are teaching things closer to calculus at earlier ages for advanced classes these days, which is why i didn't simply discount it. My 12 year old nephew has already started on elementary calc and trig in his Math classes. We barely scraped the edges of trig in 7th grade and didn't sniff at calc's rear end until 10th or 11th.. I suppose I remember my dad saying as much about the difference between what we (me and sibling's generation) were taught when I was a kid and what they were exposed to when he was one. idk.

_{You're probably right, but I was feeling less persnickety than I usually am and decided to err on the side left side of the probability curve for a change.}Answer 9 years ago

+1. You can't convert mass per volume to mass per area. At least, not without stating something which constrains the removed dimension.

9 years ago

With a length and lots of zeros. Beyond that, re-read the chapter you just covered in class.

If this isn't a homework problem, tell us about your project (just edit the question and add some text) so we can understand why you need to convert from volume to surface density. Then we might be able to help you find the data you need.