A muscle strain is the stretching or tearing of muscle fibers. Most muscle strains happen for one of two reasons: either the muscle has been stretched beyond its limits or it has been forced to contract too strongly. In mild cases, only a few muscle fibers are stretched or torn, and the muscle remains intact and strong.
Full Definition of HYDROGEN. : a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis â see element table â compare deuterium, tritium.â hyÂ·drogÂ·eÂ·nous \hÄ«-Ëdrae-ËdrÃ¤-jÉ\ nÉs. adjectiveord History of HYDROGEN. When hydrogen is burned it combines with oxygen to make water. That fact accounts for the name of this gas. The word hydrogen was formed from two Greek roots. The first, hydro- , means â water, â and the second, -gen, means â giving rise to, producing.
Hydrogen is the most abundant element, comprising about three quarters of the mass in the universe. Hydrogen is found in the water that covers 70% of the earth's surface and in all organic matter. Hydrogen is the simplest element in the universe. It is made up of one proton and one electron. Hydrogen is the lightest of all elements and gases, and is 14 times lighter than air. A gaseous hydrogen spill diffuses immediately into the air, and does not pollute the ground or groundwater.