The mass-abundance of the nine most abundant elements in the Earth's crust (see main article above) is approximately: oxygen 46%, silicon 28%, aluminum 8.2%, iron 5.6%, calcium 4.2%, sodium 2.5%, magnesium 2.4%, potassium, 2.0%, and titanium 0.61%.he mass-abundance of the nine most abundant elements in the Earth's crust (see main article above) is approximately: oxygen 46%, silicon 28%, aluminum 8.2%, iron 5.6%, calcium 4.2%, sodium 2.5%, magnesium 2.4%, potassium, 2.0%, and titanium 0.61%.
Choosing Disc Weight. Disc golf discs come in a variety of different weights. Most discs weigh between 165 and 175 grams. Some discs also come in special plastic blends designed to weigh less. The Professional Disc Golf Association regulates how heavy a disc can be based on the discs diameter.
1. 'disc' or 'disk': a flat circular object. In British English, a disc is a flat circular object. A traffic warden pointed out that I had no tax disc on the windscreen. In American English, this word is spelled disk.