Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.

An air mass is a large body of air that has similar moisture (density) and temperature characteristics. A front is a transition zone between two air masses.

A neutron is a subatomic particle found in the nucleus of an atom. It is neutral as it carries no electric charge.

Food is mixed with gastric acid and pepsin in the stomach to help break down protein.