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.
There are many historical accounts of people playing golf with a flying disc, some of which pre-date the advent of the plastic flying discs by many years. Each account was an isolated instance of recreational disc golf play, and none of the participants knew of anyone else playing disc golf.