The brass family is made up of instruments usually made of brass and are played by buzzing the lips to create vibration into a mouthpiece or tube connected to the instrument.  This vibration causes the sound to be produced.  The vibration also helps to make the pitch higher and lower.  The tighter the lips of the player, the higher the sound.  The lower the lips of the player, the lower the sound.

Brass instruments are made of a material called brass.  Brass is a metal.  The brass family can be divided into 2 smaller groups: valves and slides.
 

Instruments with valves route air through the tubes in the instrument.  Pushing a valve down opens the tube it is connected to.  The tubing creates a lower sound because it gives the air a longer distance to travel.  The second valve opens the smallest tube, the first valve opens the middle-sized tube, and the third valve opens the longest tube. 
 

Instruments with slides create lower pitches by moving the slide out, making the instrument longer.
 

Brass instruments can be found in orchestras or concert bands.  They were also used during war time on the battlefield.  The most common instruments in the brass family, from highest to lowest pitch, are:

French Horn, Trumpet, Baritone (Euphonium), Trombone, Tuba

There are many different ensembles, or groups of instruments, that use brass.  The most common are jazz bands, concert bands, orchestras, soul music, marching bands, drum and bugle corps, ska, and many popular bands in the 1970’s.
 
Trumpets and trombones are two of the oldest brass instruments, dating back to the 1700’s.  These instruments did not have valves or slides back then.  The pitches could only be created by changing the tightness and speed of the vibrations from the player’s lips.