Surface Area Argument

Sinque · 8 Apr 2008 at 16:23

CLAWS said:
Ah now that rings many bells. Quite possible this might be where I am getting mixed up.

Whats the difference here by the way? Bearing in mind I did A-level biology in 1995 and only got a C.

Apart from the fact this has nothing to do with Biology in any way, apart from the digestion part, the whole sphere surface area thing is maths.

But even still, the bigger the sphere the bigger the surface area and the volume - it's impossible for a smaller sphere to have more.

Slinwagh · 8 Apr 2008 at 16:23

Stolly said:
Easy Sphere is is smaller, but closer. Sphere A is much bigger but is miles away.

Remember kids big things close, small things far away.

Dougal, Fatherr Ted and cows are in my thoughts.

Azagoth · 8 Apr 2008 at 16:25

Slinwagh said:
Dougal, Fatherr Ted and cows are in my thoughts.

That's exactly what I thought of!

Stolly · 8 Apr 2008 at 16:26

Slinwagh said:
Dougal, Fatherr Ted and cows are in my thoughts.

Winner.

/thread.

CLAWS · 8 Apr 2008 at 16:27

Good explanations by the way folks

oddjob62 · 8 Apr 2008 at 16:27

CLAWS said:
Ah now that rings many bells. Quite possible this might be where I am getting mixed up.

Whats the difference here by the way? Bearing in mind I did A-level biology in 1995 and only got a C.

well the surface area of an object will increase as it gets bigger

eg,
a box with side 1m will have a surface area of 6m^2, volume of 1m^3
a box with side 2m will have a surface area of 24m^2 volume of 8mx3
(prays his quick calculations are correct)
so surface area has increased 4 times, volume has increased 8 times.
so for a larger object there is more less surface area to volume.

In biology you may have learned it with regards to animals and heat. Eg, a small animal will have problems staying warm as they have a high surface area to volume, while a large animal will have problems cooling down (hence why elephants have big ears to increase their surface area and aid cooling).

Vanilla · 8 Apr 2008 at 16:31

I think it actually has to do with Osmosis where PZ^Y=M?

no?

nightwish · 8 Apr 2008 at 16:38

Vanilla said:
I think it actually has to do with Osmosis where PZ^Y=M?

no?

dunno 'bout that, but the surface area to volume ratio is pretty important in chemical reactions in general. In many, if not most, reactions the reaction happens quicker if smaller particles are used. This applies to lots and lots of examples in chemistry and biology

AGD · 8 Apr 2008 at 16:44

I'm sure you can get about 50% in the biology gcse just by answering "because it increases the surface area" to every question.

Mat · 8 Apr 2008 at 16:47

bibalasvegas said:
I'm sure you can get about 50% in the biology gcse just by answering "because it increases the surface area" to every question.

I remember my sister saying exactly that about GCSE Physics when I was younger

davethe11 · 8 Apr 2008 at 17:03

I hate trick questions, they should be banned. They only serve to make people like me look stupid lol

Sinque · 8 Apr 2008 at 17:16

Mat said:
I remember my sister saying exactly that about GCSE Physics when I was younger

What meaningful help and support

Tomsk · 8 Apr 2008 at 17:40

Sphere A could be a lot rougher than sphere B.

davethe11 · 8 Apr 2008 at 17:43

or it could be hollow

nightwish · 8 Apr 2008 at 18:00

Tomsk said:
Sphere A could be a lot rougher than sphere B.

not if it's a sphere, by definition
a "rough sphere" would be just a lump or perhaps a blob!

davethe11 said:
or it could be hollow

Nope... apparently, technically, a sphere is just the surface. The volume *enclosed* by the sphere is referred to as a "ball". Bit technical for GCSE tho!

See http://en.wikipedia.org/wiki/Sphere

Nitefly · 8 Apr 2008 at 18:04

Energize said:
IT'S SURFACE TO VOLUME RATIO.

/thread

Frapple · 8 Apr 2008 at 18:10

Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration through a semi permeable membrane.

What?

and rofl at the 'because it increases surface area' I think it's the onyl reason I got BB.

davethe11 · 8 Apr 2008 at 19:20

so am I correct in assuming that surface area in some fields of science in fact means surface area to volume ratio? Wikipedia distinguishes between surface area and surface area to volume ratio (SA:V) - not that I take wikipedia as a definitive source, but is the original question regarding the spheres then ambiguous? Someone put my mind at rest so I can get some sleep tonight!

Energize · 8 Apr 2008 at 19:22

davethe11 said:
so am I correct in assuming that surface area in some fields of science in fact means surface area to volume ratio?

No.

Wikipedia distinguishes between surface area and surface area to volume ratio (SA:V) - not that I take wikipedia as a definitive source, but is the original question regarding the spheres then ambiguous? Someone put my mind at rest so I can get some sleep tonight!

The bigger sphere has a larger surface area, but a lower surface to volume ratio.

Nitefly · 8 Apr 2008 at 19:24

davethe11 said:
so am I correct in assuming that surface area in some fields of science in fact means surface area to volume ratio?

No. Either the question in the class was either:

Which out of the small and large sphere have the greatest surface area to volume ratio?

or

You have one large sphere, and several small spheres which equal the volume of the larger sphere. Which has the greatest surface area, the large sphere, or the several small ones?

Edit - Beaten