What is the difference between ballpoint pens and gel pens?

Gel pens get their name from how they write – instead of using an ink reservoir like other pens, gel pens use a water-based ink. Water-based inks flow more smoothly than oil-based inks so they provide better writing that can be done more easily, especially on non-porous surfaces. The type of ink used in ballpoint pens comes in its own pressurized cartridges, relies on tiny balls that smudge themselves onto paper to create characters. Ballpoints are generally less expensive than gel pens but take longer to dry and have a tendency to smear if you leave them uncapped for too long.