## Minimizing Surface Area of a piece of bread

For the discussion of math. Duh.

Moderators: gmalivuk, Moderators General, Prelates

Posts: 115
Joined: Wed Sep 23, 2009 10:52 pm UTC

### Minimizing Surface Area of a piece of bread

Say you're given a big semi-sphere loaf of bread. It has a volume of 32 fluid ounces and a serving size of 2. What would be the best way to eat this bread and minimize the surface area exposed of the bread to prevent it from going stale faster?

I'm asking this question cause I have a tasty pumpernickel bread right next to me.

mike-l
Posts: 2758
Joined: Tue Sep 04, 2007 2:16 am UTC

### Re: Minimizing Surface Area of a piece of bread

How big is a bite?
addams wrote:This forum has some very well educated people typing away in loops with Sourmilk. He is a lucky Sourmilk.

++\$_
Mo' Money
Posts: 2370
Joined: Thu Nov 01, 2007 4:06 am UTC

### Re: Minimizing Surface Area of a piece of bread

Cut your slice, then put it in an impermeable bag and close it. This artificially reduces the surface area.

If that isn't an option, I'm pretty sure you do best by just making one slice straight across the bread, though I don't exactly have an elegant proof.

eta oin shrdlu
Posts: 451
Joined: Sat Jan 19, 2008 4:25 am UTC

### Re: Minimizing Surface Area of a piece of bread

Along the same lines as ++\$_: Make a planar cut, then store the bread on the cutting board with the sliced surface downward. (I do this with the bread I bake; it works pretty well.)

The Geoff
Posts: 144
Joined: Wed Jun 08, 2011 6:22 am UTC

### Re: Minimizing Surface Area of a piece of bread

Compress the bread into a sphere after cutting your portion each time, surely?

Giallo
Posts: 226
Joined: Sat Jan 01, 2011 11:31 pm UTC
Location: ETH, Zürich, Switzerland
Contact:

### Re: Minimizing Surface Area of a piece of bread

You can do better:

Cut the bread in a lot of little pieces.
Recompose them and get two breads the same size of the original.
Eat one of them, sell the other.
Profit.

"Ich bin ein Teil von jener Kraft, die stets das Böse will und stets das Gute schafft."

pizzazz
Posts: 487
Joined: Fri Mar 12, 2010 4:44 pm UTC

### Re: Minimizing Surface Area of a piece of bread

5 is a lot?

PM 2Ring
Posts: 3713
Joined: Mon Jan 26, 2009 3:19 pm UTC
Location: Sydney, Australia

### Re: Minimizing Surface Area of a piece of bread

pizzazz wrote:5 is a lot?

Yes.

From KA's Q&A. This week: The bottom of reality unseeable?
gorcee wrote:[...]
A more mathematical example is boundary layer flow over a flat plate. Basically, the flow profile looks kind of like the right side of the letter U. At the flat plate, the no-slip condition applies, and the velocity is 0. As you get farther above the plate, the velocity increases, but it only increases as high as the free-stream velocity.

Formally, if you construct this system non-dimensionally (so instead of height in centimeters or whatever, we just normalize it to "units"), then the boundary layer flow only approaches free-stream flow in the limit to infinity.

Practically, however, we know this not to be the case, and we observe a point when the boundary layer flow is equal to the free stream flow within, say, 99.5%. The difference in velocity at that point can be considered to be negligible (we couldn't even measure it if we tried).

As it turns out, you don't need to go out to infinity for this case. All you need to do is go about 5 units above the flat plate to observe a 99.999999% match with free-stream. So, in that case, infinity and 5 are effectively indistinguishable.

* ponders the shape of a knife capable of doing a 5 part Banach–Tarski decomposition... *

Talith
Proved the Goldbach Conjecture
Posts: 848
Joined: Sat Nov 29, 2008 1:28 am UTC
Location: Manchester - UK

### Re: Minimizing Surface Area of a piece of bread

Spoiler:
PM 2Ring wrote:
pizzazz wrote:5 is a lot?

Yes.

From KA's Q&A. This week: The bottom of reality unseeable?
gorcee wrote:[...]
A more mathematical example is boundary layer flow over a flat plate. Basically, the flow profile looks kind of like the right side of the letter U. At the flat plate, the no-slip condition applies, and the velocity is 0. As you get farther above the plate, the velocity increases, but it only increases as high as the free-stream velocity.

Formally, if you construct this system non-dimensionally (so instead of height in centimeters or whatever, we just normalize it to "units"), then the boundary layer flow only approaches free-stream flow in the limit to infinity.

Practically, however, we know this not to be the case, and we observe a point when the boundary layer flow is equal to the free stream flow within, say, 99.5%. The difference in velocity at that point can be considered to be negligible (we couldn't even measure it if we tried).

As it turns out, you don't need to go out to infinity for this case. All you need to do is go about 5 units above the flat plate to observe a 99.999999% match with free-stream. So, in that case, infinity and 5 are effectively indistinguishable.

* ponders the shape of a knife capable of doing a 5 part Banach–Tarski decomposition... *

Well really you need an infinitely fine laser and an infinite precision rotation machine...... should be possible