A clove hitch is a fast way to connect the middle of a rope to another object. It is easiest to tie a clove hitch around an object where you have access to the end of the object (e.g., a carabiner, fire hydrant, etc) and more complicated to tie around an object where you don't have access to a post-like end (e.g., a telephone pole). The real advantage of a clove hitch is that you can quickly tie it in the middle of a rope.
A disadvantage of clove hitches is that they can slip when object the hitch is tied around is smooth and has a "significantly" larger diameter than the rope—they do not slip when tied around carabiners. Clove hitches can be difficult to untie after being heavily loaded.
To tie a clove using the middle of a rope:
To tie a clove using the end of a rope:
The "critical point test" (aka "scissors test") requires that if any one item fails, nobody should be injured.
A "bend" is a knot that joins two ropes.
A "hitch" is a type of knot that must be tied around another object.
The "whistle test" requires that if all rescuers let go, nobody should be injured.