As children move towards middle and late childhood, the relationship between physical activity and motor skill competence evolves and strengthens (Stodden et al. 2008). During middle childhood, a childâs perceived motor competence more closely estimates their actual motor skill competence.
In 1842 Gustav Mosander separated yttria, found in the mineral gadolinite, into three fractions which he called yttria, erbia, and terbia. The names erbia and terbia became confused in this early period. After 1860, Mosander's terbia was known as erbia, and after 1877, the earlier known erbia became terbia. The erbia of this period was later shown to consist of five oxides, now known as erbia, scandia, holmia, thulia and ytterbia.
Neon was discovered by Sir William Ramsay, Morris W. Travers at 1898 in London, England. Origin of name: from the Greek word neon meaning new. Neon was discovered by Sir William Ramsay and Morris Travers in 1898 very shortly after their discovery of the element krypton. Both elements were discovered through work on liquid air.