SHOE SIZE OF BOY AND GIRL IN US

A shoe size is an indication of the fitting size of a shoe for a person.

There are a number of different shoe-size systems used worldwide. While all shoe sizes use a number to indicate the length of the shoe, they differ in exactly what they measure, what unit of measurement they use, and where the size 0 (or 1) is positioned. Some systems also indicate the shoe width, sometimes also as a number, but in many cases by one or more letters. Some regions use different shoe-size systems for different types of shoes (e.g. men's, women's, children's, sport, and safety shoes). This article sets out several complexities in the definition of shoe sizes. In practice, shoes are often tried on for both size and fit before they are purchased.

Foot versus shoe and last 

The length of a person's foot is commonly defined as the distance between two parallel lines that are perpendicular to the foot and in contact with the most prominent toe and the most prominent part of the heel. Foot length is measured with the subject standing barefoot and the weight of the body equally distributed between both feet.

The sizes of the left and right feet are often slightly different. In this case, both feet are measured, and purchasers of mass-produced shoes are advised to purchase a shoe size based on the larger foot, as most retailers do not sell pairs of shoes in non-matching sizes.

Each size of shoe is considered suitable for a small interval of foot lengths, typically limited by half-point of the shoe size system.

A shoe-size system can refer to three characteristic lengths:

The median length of feet for which a shoe is suitable. For customers, this measure has the advantage of being directly related to their body measures. It applies equally to any type, form, or material of shoe. However, this measure is less popular with manufacturers, because it requires them to test carefully for each new shoe model, for which range of foot sizes it is recommendable. It puts on the manufacturer the burden of ensuring that the shoe will fit a foot of a given length.

The length of the inner cavity of the shoe. This measure has the advantage that it can be measured easily on the finished product. However, it will vary with manufacturing tolerances and only gives the customer very crude information about the range of foot sizes for which the shoe is suitable.

The length of the "last", the foot-shaped template over which the shoe is manufactured. This measure is the easiest one for the manufacturer to use, because it identifies only the tool used to produce the shoe. It makes no promise about manufacturing tolerances or for what size of foot the shoe is actually suitable. It leaves all responsibility and risk of choosing the correct size with the customer. Further, the last can be measured in several different ways, resulting in different measurements.

All these measures differ substantially from one another for the same shoe. For example, the inner cavity of a shoe must typically be 15 mm longer than the foot, and the shoe last would be 2 size points larger than the foot, but this varies between different types of shoes and the shoe size system used. The typical range lies between 1⁄2 to 2⁄3 inch (12.7 to 16.9 mm) for the UK/US size system and 4⁄3 to 5⁄3 cm (13.3 to 16.7 mm) for the European size system, but may extend to 1⁄4 to 3⁄4 inch (6.4 to 19.1 mm) and 2⁄3 to 6⁄3 cm (6.7 to 20.0 mm).

Length

Sizing systems also differ in the units of measurement they use. This also results in different increments between shoe sizes, because usually only "full" or "half" sizes are made.

The following length units are commonly used today to define shoe-size systems:

The Paris point equates to 2⁄3 centimetre (6.67 mm; 0.26 in). Whole sizes are incremented by 1 Paris point; this corresponds to 3.33 millimetres (0.131 in) between half sizes. This unit is commonly used in Continental Europe, and Russia and former USSR countries.

The barleycorn is an old English unit that equates to 1⁄3 inch (8.47 mm). This is the basis for current UK and North American shoe sizes, with the largest shoe size taken as twelve inches (a size 12) i.e. 30.5 cm, and then counting backwards in barleycorn units, so a size 11 is 11.67 inches or 29.6 cm.

Metric measurements in millimetres (mm) or centimetres (cm), with intervals of 5 mm and 7.5 mm are used in the international Mondopoint system (USSR/Russia and East Asia).

Since the early 2000s, labels on sports shoes typically include sizes measured in all four systems: EU, UK, US and cm (Mondopoint).

Zero point

The sizing systems also place size 0 (or 1) at different locations:

Size 0 as a foot's length of 0. The shoe size is directly proportional to the length of the foot in the chosen unit of measurement. Sizes of children's, men's, and women's shoes, as well as sizes of different types of shoes, can be compared directly. This is used with the Mondopoint system (USSR/Russia and East Asia).

Size 0 as the length of the shoe's inner cavity of 0. The shoe size is then directly proportional to the inner length of the shoe. This is used with systems that also take the measurement from the shoe. While sizes of children's, men's and women's shoes can be compared directly, this is not necessarily true for different types of shoes that require a different amount of "wiggle room" in the toe box. This is used with the Continental European system.

Size 0 (or 1) can just be simply a shoe of a given length. Typically, this will be the shortest length deemed practical; but this can be different for children's, teenagers', men's, and women's shoes - making it impossible to compare sizes. For example, a women's shoe at size 8 is a different length from a men's shoe at size 8 in the US system, but not the British.

Width

Some systems also include the width of a foot (or the girth of a shoe last), but do so in a variety of ways:

Measured foot width in millimetres (mm) - this is done with the Mondopoint system.

Measured width as a letter (or combination of letters), which is taken from a table (indexed to length and width/girth) or just assigned on an ad-hoc basis. Examples are (each starting with the narrowest width):

AAA, AA, A, B, C, D, E, EE, EEE is the typical North American system and follows the brannock device standards, per the system B is narrow, C is regular, D is medium, E is wide, EE is extra wide and so on. The unlettered D size is the norm for men and B for women.

4A, 3A, 2A, A, B, C, D, E, 2E, 3E, 4E, 5E, 6E (variant North American).

C, D, E, F, G, H (common UK; "medium" is usually F but varies by manufacturer—makers Edward Green and Crockett & Jones, among others, use E instead, but one maker's E is not necessarily the same size as another's).

N (narrow), M (medium) or R (regular), W (wide).

For children's sizes in North America, typical letters used are M or B (medium), W or D (wide), EW or 2E (extra wide).

The width for which these sizes are suitable can vary significantly between manufacturers. The A–E width indicators used by most American, Canadian, and some British shoe manufacturers are typically based on the width of the foot, and common step sizes are 3⁄16 inch (4.8 mm).

Difficulties

There could be differences between various shoe size tables from shoemakers and shoe stores. They are usually due to the following factors:

Different methods of measuring the shoes, different manufacturing processes, or different allowances even when the same system is used.

An indication in centimetres or inches can mean the length of the foot or the length of the shoe's inner cavity.

Differing amounts of wiggle room required for different sizes of shoes.

For wide feet, a shoe several sizes larger (and actually too long) may be required and may also result in inconsistent size indications when different typical widths are attributed to specific shoe sizing systems.

Some tables for children take future growth into account. The shoe size is then larger than what would correspond to the actual length of the foot.

Conversion tables available on the Web often contain obvious errors, not taking into account different zero points or wiggle room.

Although shoe size systems are not fully standardised, the ISO/TC 137 had released a technical specification ISO/TS 19407:2015 for converting shoe sizes across various local sizing systems. Even though the problem of converting shoe sizes accurately has yet to be fully resolved, this standard serves as "a good compromise solution" for shoe-buyers.

Shoe size in the United Kingdom, Ireland, India, Pakistan and South Africa is based on the length of the last used to make the shoes, measured in barleycorns (1⁄3 inch) starting from the smallest size deemed practical, which is called size zero. It is not formally standardised. Note that the last is typically longer than the foot heel to toe length by 1⁄2 to 2⁄3 in or 1+1⁄2 to 2 barleycorns, so to determine the shoe size based on actual foot length one must add 2 barleycorns.

A child's size zero is equivalent to 4 inches (a hand = 12 barleycorns = 10.16 cm), and the sizes go up to size 13+1⁄2 (measuring 25+1⁄2 barleycorns, or 8+1⁄2 inches (21.59 cm)). Thus, the calculation for a children's shoe size in the UK is:

child shoe size (barleycorns) = 3 × last length (in) − 12

equivalent to:

child shoe size (barleycorns) ≈ 3 × foot length (in) − 10.

An adult size one is then the next size up (26 barleycorns, or 8+2⁄3 in (22.01 cm)) and each size up continues the progression in barleycorns.The calculation for an adult shoe size in the UK is thus:

adult shoe size (barleycorns) = 3 × last length (in) − 25

equivalent to:

adult shoe size (barleycorns) ≈ 3 × foot length (in) − 23.

Although this sizing standard is nominally for both men and women, some manufacturers use different numbering for women's UK sizing.

In Australia and New Zealand, the UK system is followed for men and children's footwear. Women's footwear follows the US sizings.

In Mexico, shoes are sized either according to the foot length they are intended to fit, in cm, or alternatively to another variation of the barleycorn system, with sizes calculated approximately as:

adult shoe size (barleycorns) = 3 × last length (in) − 25+1⁄2

equivalent to:

adult shoe size (barleycorns) ≈ 3 × foot length (in) − 23+1⁄2.

EID MUBARAK

 

Asteroid headed towards Earth -Impacting the Earth

 

A huge asteroid is coming to earth.so we must understand about  An asteroid. Asteroid headed towards Earth may arrive on Valentine's Day 2046 - Nasa. Image caption, Asteroid 2023 DW has a better chance of hitting a date of 14 February than our planet, NASA says. A newly detected asteroid has a very small chance of impacting the Earth in 2046, Nasa tweeted.

An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. 

Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost 1,000 km (600 mi) across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to complete a full circuit of the Sun.

Asteroids have been historically observed from Earth; the Galileo spacecraft provided the first close observation of an asteroid. Several dedicated missions to asteroids were subsequently launched by NASA and JAXA, with plans for other missions in progress. NASA's NEAR Shoemaker studied Eros, and Dawn observed Vesta and Ceres. JAXA's missions Hayabusa and Hayabusa2 studied and returned samples of Itokawa and Ryugu, respectively. OSIRIS-REx studied Bennu, collecting a sample in 2020 to be delivered back to Earth in 2023. NASA's Lucy, launched in 2021, will study ten different asteroids, two from the main belt and eight Jupiter trojans. Psyche, scheduled for launch in 2023, will study a metallic asteroid of the same name.

Near-Earth asteroids can threaten all life on the planet; an asteroid impact event resulted in the Cretaceous–Paleogene extinction. Different asteroid deflection strategies have been proposed; the Double Asteroid Redirection Test spacecraft, or DART, was launched in 2021 and intentionally impacted Dimorphos in September 2022, successfully altering its orbit by crashing into it.

The first discovered asteroid, Ceres, was originally considered a new planet. It was followed by the discovery of other similar bodies, which with the equipment of the time appeared to be points of light like stars, showing little or no planetary disc, though readily distinguishable from stars due to their apparent motions. This prompted the astronomer Sir William Herschel to propose the term asteroid, coined in Greek as ἀστεροειδής, or asteroeidēs, meaning 'star-like, star-shaped', and derived from the Ancient Greek ἀστήρ astēr 'star, planet'. In the early second half of the 19th century, the terms asteroid and planet (not always qualified as "minor") were still used interchangeably.

Traditionally, small bodies orbiting the Sun were classified as comets, asteroids, or meteoroids, with anything smaller than one meter across being called a meteoroid. The term asteroid never had a formal definition,[28] with the broader term small Solar System bodies being preferred by the International Astronomical Union (IAU). As no IAU definition exists, asteroid can be defined as "an irregularly shaped rocky body orbiting the Sun that does not qualify as a planet or a dwarf planet under the IAU definitions of those terms".

When found, asteroids were seen as a class of objects distinct from comets, and there was no unified term for the two until small Solar System body was coined in 2006. The main difference between an asteroid and a comet is that a comet shows a coma due to sublimation of near-surface ices by solar radiation. A few objects have ended up being dual-listed because they were first classified as minor planets but later showed evidence of cometary activity. Conversely, some (perhaps all) comets are eventually depleted of their surface volatile ices and become asteroid-like. A further distinction is that comets typically have more eccentric orbits than most asteroids; "asteroids" with notably eccentric orbits are probably dormant or extinct comets.

For almost two centuries, from the discovery of Ceres in 1801 until the discovery of the first centaur, 2060 Chiron in 1977, all known asteroids spent most of their time at or within the orbit of Jupiter, though a few such as 944 Hidalgo ventured far beyond Jupiter for part of their orbit. When astronomers started finding more small bodies that permanently resided further out than Jupiter, now called centaurs, they numbered them among the traditional asteroids. There was debate over whether these objects should be considered asteroids or given a new classification. Then, when the first trans-Neptunian object (other than Pluto), 15760 Albion, was discovered in 1992, and especially when large numbers of similar objects started turning up, new terms were invented to sidestep the issue: Kuiper-belt object, trans-Neptunian object, scattered-disc object, and so on. They inhabit the cold outer reaches of the Solar System where ices remain solid and comet-like bodies are not expected to exhibit much cometary activity; if centaurs or trans-Neptunian objects were to venture close to the Sun, their volatile ices would sublimate, and traditional approaches would classify them as comets and not asteroids.

The innermost of these are the Kuiper-belt objects, called "objects" partly to avoid the need to classify them as asteroids or comets. They are thought to be predominantly comet-like in composition, though some may be more akin to asteroids. Furthermore, most do not have the highly eccentric orbits associated with comets, and the ones so far discovered are larger than traditional comet nuclei. (The much more distant Oort cloud is hypothesized to be the main reservoir of dormant comets.) Other recent observations, such as the analysis of the cometary dust collected by the Stardust probe, are increasingly blurring the distinction between comets and asteroids, suggesting "a continuum between asteroids and comets" rather than a sharp dividing line.

The minor planets beyond Jupiter's orbit are sometimes also called "asteroids", especially in popular presentations. However, it is becoming increasingly common for the term asteroid to be restricted to minor planets of the inner Solar System. Therefore, this article will restrict itself for the most part to the classical asteroids: objects of the asteroid belt, Jupiter trojans, and near-Earth objects.

When the IAU introduced the class small Solar System bodies in 2006 to include most objects previously classified as minor planets and comets, they created the class of dwarf planets for the largest minor planets – those that have enough mass to have become ellipsoidal under their own gravity. According to the IAU, "the term 'minor planet' may still be used, but generally, the term 'Small Solar System Body' will be preferred." Currently only the largest object in the asteroid belt, Ceres, at about 975 km (606 mi) across, has been placed in the dwarf planet category.