The Triple Alliance:
This was a three way alliance formed in 1882 between Germany, Austria-Hungary and Italy. It was similar to The Dual Alliance three years earlier between Germany and Austria-Hungary. The alliance was made so that they would defend each other in the event of an attack from another power, it was not meant to be aggresive.
The main reasons they signed it were to seperate France and Russia by forming a central European block, they all wanted protection from Russia and France as well as to expand out into an empire. Both the Duel and Triple Alliance were formed in Secret.
The Triple Entente:
This was a series of three alliances between Russia, France and Britain. These alliances were formed in 1893, 1903-4 and 1907. The main purpose was to counter act the Triple Alliance which seemed very threatning.
Britain was scared of the rising threat of the German navy and "Weltpolitik", France wanted to take Morocco and Alsace and Lorraine and all Russia really wanted was help with their economy and poor industry. They also thought that the Triple Alliance was aggresive.
Germany - Kaiser Wilhelm always wanted to have an empire which could rival his cousin's, King George of Britain. He followed "Weltpolitik" in which he wanted to "get a place in the sun", but to do that he had to build up a very powerful navy.
Britain - Under Queen Victoria, our foriegn policy was "Splendid Isolationism" in which we stayed out of international affairs. But under King George, we aimed to leave that behind and start protecting our interests, Empire and naval dominance which was probably caused by the sudden rise of Germany and their navy.
France - France wanted to expand their empire in to Morocco as it was an independent nation but they also wanted to retake Alsace and Lorraine which they lost to Germany in 1871. Because of this loss, France were very scared but also very bitter towards Germany.
Austria-Hungary - Austria Hungary was determined to expand their empire in to the Balkans due to its natural resources. They were looking to take over and add countries such as Bosnia and Serbia to their large empire.
Russia - Russia saw themselves as the "protecter of the slavs" and wanted to garuntee slavic independence from Austria. Despite having the largest army, it was weak so they were deperate for friends.