14. Illumination
Lighting your way in the dark progressed from campfires and flaming torches to oil lanterns to electric lights and eventually to flashlights compact enough to fit in your pocket. There you go instant illumination in the palm of your hand that can light the darkest path. Frankly, it made modern civilization possible. Most of the time the Doctor has a torch when exploring, but sometimes not. There are times you watch as he switches on the screwdriver and it shines a bright light to guide his way. This was first seen in the animated Dreamland where the Tenth Doctor used the screwdriver as a torch, three times no less. The Eleventh Doctor matched that in Closing Time while exploring the wrecked Cybermen spaceship. Both the Tenth and Eleventh Doctors are tied with four illumination uses apiece. Sonoluminescence creates tiny bubbles in water that contract rapidly and create light. Though there's no water in the immediate area of the screwdriver advances in cavitation methods using other materials in the air could function in the same manner. We'll just have to wait for science to catch up.