What is a backbeat in a song?
A heavy rhythmic emphasis on beats 2 and 4 within a 4-beat bar. Many rock drum patterns are based around the kick (bass) drum playing on beats 1 & 3, with the snare drum sounding the backbeat on beats 2 and 4.
How do you tell if a song has a backbeat?
A backbeat takes place at the level of the beat. A backbeat is when you emphasize beats 2 and 4 instead of 1 and 3 (often with a snare, for example). So if you're tapping your foot and you feel an emphasis on the foot, but on beats 2 and 4, that's a backbeat.