Chemical element element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust. Chemical elements constitute all of the ordinary matter of the universe. However astronomical observations suggest that ordinary observable matter makes up only about 15% of the matter in the universe: the remainder is dark matter; the composition of this is unknown, but it is not composed of chemical elements. The two lightest elements, hydrogen and helium, were mostly formed in the Big Bang and are the most common elements in the universe. The next three elements (lithium, beryllium and boron) were formed mostly
Solid ground floor mm to 225 mm. Though due to poor workmanship and dust this type of floor finish fails through lifting. Terrazo: Terrazo consists of a coloured element binder or matrix and marble chips mixed to specified proportions. The finish is hardwearing, attractive and resistant to chemical attack. Ebonite strips divide the terrazo into bays to avoid shrinkage and expansion. Solid ground floor A solid ground floor consists of a layer of concrete, which in the case of a domestic building will be the surface layer brought up to ground floor level with hardcore filling under it. The advantage of a solid