Free climbing encompasses every other type of rock climbing other than aid climbing. It refers to climbing using only your hands and feet on natural features of the rock to move upwards. Depending on the specific style, various types of gear are used to protect against falling—but never to help the climber move upward. Free climbing can be further broken down into two categories: roped and unroped.
Roped Free Climbing
Roped free climbing is climbing with a rope attached to a harness to protect against falls. It has three main categories: traditional (or “trad” ), sport, and top rope. Top rope climbing involves building an anchor above the climb before climbing it. Trad and sport climbing are forms of lead climbing, where the climber starts at the bottom of the climb and places protection to clip their rope to as they go up. The type of protection used is the main difference between trad and sport climbing.
Unroped Free Climbing
Unroped free climbing is climbing without ropes to protect against falls. It comes in two main categories: bouldering and free soloing.
Free Soloing has recently been made famous by climbers like Alex Honnold, although it’s been practiced among climbers for a long time. During a free solo ascent, a climber uses only their hands and feet on the rock as protection against falls. Because free soloing is so dangerous, most practitioners only free solo climbs that they’ve practiced while roped many times.
Bouldering is unroped free climbing that takes place on rocks and walls that are low to the ground, so that the risk from falls is minimal. Whether practiced outdoors or indoors at a climbing gym, there are usually soft pads called “crash pads” at the base of the climb to protect climbers if they fall. Especially when climbing outdoors, boulderers also have other people (called “spotters”) help guide them onto the crash pads in case of a fall. It’s probably the most popular style of climbing today because of the minimal amount of gear it requires.
Aid climbing uses permanent or removable protection that’s placed into the rock to help the climber make upward progress. It’s usually reserved for climbs that are too difficult for the lead climber to complete using only the natural rock surfaces. The climber attaches a ladder made of webbing (called an aider) to a protection piece, then stands or pulls herself up on the ladder, then repeats the process. Aid climbers used to hammer pitons (wedge-shaped pieces of metal) into the rock for protection, which permanently damaged the rock. Today most aid climbers practice “clean aid”, meaning they use removable protection (cams, nuts, etc.) or permanent bolts that are pre-drilled into the rock. The best way to understand aid climbing is to see it. Here’s a simple video from SuperTopo explaining how to aid climb.