Military technology developed rapidly during World War I to include advancements such as tanks, flame throwers, poison gas, tracer bullets, interrupter gear, air traffic control, depth charges, hydroplanes, aircraft carriers, pilotless drones and mobile X-ray machines. The Germans and the Allies raced to develop these advancements.
Tanks changed the nature of trench warfare by actually allowing opposing troops to get close to one another without being mowed down. The first tank used was British Mark 1 at the Somme in 1916. Modern flamethrowers were perfected by the Germans in 1915 and used in trench warfare to burn the enemy alive in the trench without destroying the trench with a grenade.
Poison gas was used extensively by both sides. They raced one another to make more and more lethal gases capable of penetrating gas masks.
Tracer bullets helped the British by leaving phosphorescent trails at night and causing the German zeppelins to explode because of their flammable agent. Interrupter gear was adopted by the Germans in 1915, allowing synchronized gunfire in between airplane blades. Air traffic control allowed for two-way radios between pilots in the air and an operator on the ground. Depth charges were the Allies' solution to German U-boats. These underwater bombs sunk their first U-boat in 1916. Hydroplanes were underwater microphones developed for locating German U-boats.
Though too imprecise to use effectively, the first pilotless drones were created by the U.S. Navy in 1916-17. The medical advance of the mobile X-ray machines allowed battlefield doctors and nurses to treat the injured soldiers must faster.