But unlike alkanes, alkines contain a double bond. And in this lecture, we're going to examine exactly what a double bond is. So let's begin by looking at the simplest alkhine, known as ethylene, also known as ethylene. Now, ethylene is composed of two carbons connected by a double bond and two H atoms found on both sides of those carbons. So let's begin by building or creating this ethylene molecule. So let's create it using a methylratical.