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lightarrow
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Sorry if already asked:
Why round, thin, fried potatos often comes out with a "saddle" shape?
Thanks.
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lightarrow
Why round, thin, fried potatos often comes out with a "saddle" shape?
Thanks.
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lightarrow
A deformation into a saddle indicates that the center has contracted (more than the periphery). Or that the periphery has expanded (more than the center).lightarrow said:Why round, thin, fried potatos often comes out with a "saddle" shape?
Can you help me understand it?A.T. said:A deformation into a saddle indicates that the center has contracted (more than the periphery). Or that the periphery has expanded (more than the center).
Yeah, like why not a dome? How do the areas and circumferences relate between shapes? I believe it has something to do with efficiency being greatest for the circle. More area can be added but not less, without holes. So, if say you keep the circumfernce the same and decrease the area, it has to bend. If you increase the circumference and hold the area it has to bend. Nature likes circles.lightarrow said:Can you help me understand it?
Thanks
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lightarrow
My best guess: When they are fried, heat is applied to one side of the potato slice, which causes that side to contract.lightarrow said:Sorry if already asked:
Why round, thin, fried potatos often comes out with a "saddle" shape?
lightarrow said:Can you help me understand it?
Look up negative vs. positive curvature.itfitmewelltoo said:Yeah, like why not a dome? How do the areas and circumferences relate between shapes?
Being somewhat lazy, I just googled it:lightarrow said:Sorry if already asked:
Why round, thin, fried potatos often comes out with a "saddle" shape?
Thanks.
--
lightarrow
A.T. said:A deformation into a saddle indicates that the center has contracted (more than the periphery). Or that the periphery has expanded (more than the center).
I now suspect that this is closer to the answer than A.T.'s answer, as my potato peeler thickness chips also did not curl in the oven.Mark44 said:My best guess: When they are fried, heat is applied to one side of the potato slice, which causes that side to contract.
The heat removes water, causing the heated side to shrink, rising in the middle. If you flip them over, heat is applies only to the center of the slice, not to the whole slice like when they were put into the frying pan.
That is good - as far as it goes. But then we also find an opposite curvature (across the 'minor axis) in many chips. That could be due later to tension in the central part which is supported more by the crisper, harder edge which can still rotate a bit and allow the tension in the longer major axis to give a small amount of opposite curvature.A.T. said:A deformation into a saddle indicates that the center has contracted (more than the periphery). Or that the periphery has expanded (more than the center).
Not sure what you mean. Intrinsic curvature (saddle vs. sphere) is based on both axes. Opposite extrinsic curvatures of the two axes is what defines negative curvature (saddle).sophiecentaur said:But then we also find an opposite curvature (across the 'minor axis)...
The take a disc and curl it up. There need be only one axis of curvature as there is no area distortion. A saddle, I would have said, has curvature on another axis as well.A.T. said:Not sure what you mean. Intrinsic curvature (saddle vs. sphere) is based on both axes. Opposite extrinsic curvatures of the two axes is what defines negative curvature (saddle).
Converting a flat disc into a saddle requires area distortion. A saddle has negative intrinsic curvature.sophiecentaur said:There need be only one axis of curvature as there is no area distortion.
The negative intrinsic curvature already captures that:sophiecentaur said:A saddle, I would have said, has curvature on another axis as well.
Ok. And (think) I got why (possible explanation) a contraction of the centre or an expansion of the outer part makes it in a saddle shape: if we draw in the disk's outer part a circle centred in the disk' centre, it has a greater length than one drawn near the inner part, is it right?A.T. said:Converting a flat disc into a saddle requires area distortion. A saddle has negative intrinsic curvature.
The "absolute sense" that you speak of would be extrinsic curvature -- curvature of the two dimensional shape based on its embedding in a three dimensional Euclidean geometry. This is the sort of curvature you get if you roll a piece of paper up into a tube.lightarrow said:Let's say the greatest curvatures (in absolute sense) are along the x and y-axis and that the first is positive and the second is negative (according to some coordinate system). The question is: what physically made the disk/potato curl positively along x and negatively along y instead of the opposite? And why just x (and y) and not another couple of (necessarily orthogonal?) axis?
In real life you always have some inhomogeneity (of the material and the external conditions), that determines which part folds which way.lightarrow said:And why just x (and y) and not another couple of (necessarily orthogonal?) axis?
No, I was referring to the sign: with "absolute sense" I intended "absolute value", since one is positive and the other negative; sorry for the bad english.jbriggs444 said:The "absolute sense" that you speak of would be extrinsic curvature -- curvature of the two dimensional shape based on its embedding in a three dimensional Euclidean geometry. This is the sort of curvature you get if you roll a piece of paper up into a tube.
Thanks.. No self respecting topologist would be caught dead using the term absolute to describe extrinsic curvature. Instead, extrinsic curvature would be better termed relative. It is curvature relative to an embedding.
The other sort of curvature is intrinsic curvature -- curvature that a hypothetical ant walking on the surface of the potato chip could measure by carefully counting his steps. For example, the length of a path around the edge of a potato chip (its circumference) is larger than pi times the length of a path through the center (its diameter). That's negative curvature. By contrast, a hemisphere has positive curvature. The length of a path around the rim of a hemisphere is shorter than pi times the length of a path from rim to rim through the center. [This is a bit hand-wavy. One has to nail down additional details to arrive at a rigorous measurement procedure for intrinsic curvature]
Rule of thumb is that if you can flatten a shape out without wrinkling, tearing or stretching it, then any pre-existing curvature was extrinsic. If you cannot flatten it out without wrinkling, tearing or stretching then the pre-existing curvature was intrinsic.Since the choice of x and y axes is arbitrary and can be made at random (as are the conventions for "upward" and "downward"), the chance that the potato chip has upward or downward extrinsic curvature about the x-axis is indeed random.
Thanks.A.T. said:In real life you always have some inhomogeneity (of the material and the external conditions), that determines which part folds which way.
The round shape of fried potato slices is primarily due to the slicing process. When potatoes are cut into thin slices, they naturally form a circular shape. Additionally, the heat from frying causes the edges of the potato slices to curl up, further enhancing the round shape.
Yes, the shape of fried potato slices can be changed by altering the slicing technique. For example, cutting the potato slices at an angle can result in oval or oblong shapes. Additionally, using a mandoline or a spiralizer can create unique shapes such as shoestring or curly fries.
Uneven shapes in fried potato slices can be caused by variations in the potato itself. Potatoes are not always perfectly round, so when they are sliced, the resulting shapes may be irregular. Additionally, the frying process can also cause some slices to shrink or expand, resulting in uneven shapes.
Yes, different frying methods can affect the shape of potato slices. For example, deep frying tends to result in a more uniform round shape, while pan frying can result in more irregular shapes. Additionally, the type of oil used and the temperature at which it is fried can also impact the final shape of potato slices.
Yes, the shape of fried potato slices can affect their taste. The thickness and shape of potato slices can impact the texture and crunchiness of the final product. Additionally, some people may perceive differently shaped potato slices to have varying levels of crispiness or softness, which can affect their overall taste experience.