Because music is heard over a period of time, one of the main ways music is organized is by dividing that time up into short periods called beats. In most music, things tend to happen right at the beginning of each beat. This makes the beat easy to hear and feel. When you clap your hands, tap your toes, or dance, you are "moving to the beat". Your claps are sounding at the beginning of the beat, too. This is also called being "on the downbeat", because it is the time when the conductor's baton15 hits the bottom of its path and starts moving up again.
Listen to excerpts A, B, C and D. Can you clap your hands, tap your feet, or otherwise move "to the beat"? Can you feel the 1-2-1-2 or 1-2-3-1-2-3 of the meter? Is there a piece in which it is easier or harder to feel the beat?
The downbeat is the strongest part of the beat, but some downbeats are stronger than others. Usually a pattern can be heard in the beats: strong-weak-weak-strong-weak-weak, or strong-weak-strong- weak. So beats are organized even further by grouping them into bars, or measures. (The two words mean the same thing.) For example, for music with a beat pattern of strong-weak-weakstrong- weak-weak, or 1-2-3-1-2-3, a measure would have three beats in it. The time signature tells you two things: how many beats there are in each measure, and what type of note gets a beat.
Listen again to the music in Example 1.4. Instead of clapping, count each beat. Decide whether the music has 2, 3, or 4 beats per measure. In other words, does it feel more natural to count 1-2-1-2, 1-2-3-1-2-3, or 1-2-3-4-1-2-3-4?