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.
Copernicium was discovered during fusion experiments at the Centre for Heavy Ion Research in Germany in 1996. The name was proposed by Prof Sigurd Hofmann. Under the IUPAC rules, his team were forbidden from naming the element after a living person. 'After IUPAC officially recognised our discovery, we â that is all scientists involved in the discovery â agreed on proposing the name copernicium for the new element 112. 'We would like to honour an outstanding scientist who changed our view of the world,' said Prof Hofmann, head of the discovering team.