The diameter of a hydrogen atom is approximately 1.06 ✕ 10−10 m, as defined by the diameter of the spherical electron cloud around the nucleus. the hydrogen nucleus has a diameter of approximately 2.40 ✕ 10−15 m. (a) imagine a scale model of a hydrogen atom where its diameter is represented by the height of the empire state building (1454 ft to the top of its antenna). in this model, what would be the diameter of the nucleus in millimeters? mm (b) the atom is how many times larger in volume than its nucleus? va vn =

a) 10.0 mm

b) 8.7 x 10¹³ times

Explanation:

Atom diameter = 1.06 x 10⁻¹⁰ m   100%

Nucleus diameter = 2.40 x 10⁻¹⁵ m   x

x = 2.26 x 10⁻³ %

The nucleus diameter is equivalent to 2.26 x 10⁻³ % of the total atom size.

a) The Empire State Building model:

1 ft = 304.8 mm

1454 ft = 443179.2 mm

443179.2 mm 100%

        y             2.26 x 10⁻³ %

              y = 10.0 mm

In this model,  the diameter of the nucleus would be 10.0 mm.

b) Sphere volume: V =(4 · π · r³ )/3

V atom = (4 . π .( 0.53x10⁻¹⁰)³ )/3

V atom = 6.2 x 10⁻³¹ m³

V nucleus = (4 . π .( 1.2x10⁻¹⁵)³ )/3

V nucleus = 7.2 x 10⁻⁴⁵ m³

V atom / V nucleus = 6.2 x 10⁻³¹ m³ / 7.2 x 10⁻⁴⁵ m³

V atom / V nucleus = 8.7 x 10¹³

The atom is  times 8.7 x 10¹³ larger in volume than its nucleus.        

pre-sliced bread is a relatively recent development in baking technology. previous to that, it was always sold in a bakery in daily-made contiguous loaves with no wrapping, and was moderately perishable, usually being used with a day or two (which is why every bakery had a discounted “day-old” bread table.) therefore, pre-sliced bread would grow stale quickly. the hard crust provided a protective layer, and once the exposed dry slice left from the previous cut was removed, the interior was still soft.

what keeps bread soft is the moisture retained in the crumb (the light spongy part that’s not crust). the reason the crust develops is the surface of the dough gets exposed to hot dry air during baking which browns the outer layer and seals it, preventing all the moisture from escaping the dough. longer exposure to air will also eventually cause your bread to lose flavor and become stale.

people were used to cutting slices as they needed them and storing bread in a specially-made wooden or metal breadbox or pail with a lid to preserve it longer, but the first automatically sliced commercial loaves were produced on july 6, 1928, in chillicothe, missouri, using a machine invented by otto rohwedder, an iowa-born, missouri-based jeweler.[1] pre-sliced bread would indeed dry out, were it not for another 20th century technology: the plastic bag. bread could now be pre-sliced, and if the enclosing bag remains sealed as much as possible, the bread will remain soft and fresh for longer than if sitting unwrapped on a shelf or enclosed in a bread box that is not air-tight. sealed packaging meant bread could also be sold on store shelves and eliminate frequent trips to a bakery.

sealing bread in a plastic bag had another effect: the moisture in the loaf will re-distribute into the crust and soften it, which is sometimes more pleasing in a sandwich - especially for children whose teeth might not yet be strong enough to tear through a hard crust. a homemade loaf of bread can be sealed in a bag overnight and the crust will become soft like store-bought sandwich bread.

these were novel changes in how bread was produced and sold, which led to the coining of the phrase “the greatest thing since sliced bread.”

personal, she chose to do it.