The Origins

Rock music first started out in the 1940s. At the time, the popular music at the time was country and blues, but over time, this morphed into a heavier sound aided by guitars and a steady drumbeat. Artists such as Chuck Berry and Ray Charles pioneered the rock movement. In contrast to the soft, innocent pop music at the time, the aggressive nature of rock suggested a sexual freedom that was a shock during that conservative age. This continued into the 1960s when the Rolling Stones elevated rock music with controversial songs that embraced sex and youth rebellion, followed by many other bands such as the Beatles and the Ramones. In the 1970s, rock evolved in many different ways, with bands such as Led Zeppelin, Black Sabbath, and Deep Purple adding deeper, darker, and heavier elements to their music, which would be known as "heavy metal". Around the same time, bands such as Pink Floyd, and The Jimi Hendrix Experience started adding psychedelic elements to rock, and from then on, rock became one of the most popular music genres in the 20th century.

The Instruments

Throughout rock history, there has been a wide variety of instruments used in shaping its distinct sound. Regular and typical subgenres of rock, such as Classic Rock or Hard Rock, typically use three or four base instruments: Drums and Bass guitar (and occasionally, rhythm guitar) provide the rhythm and groove of the song, whereas the lead guitar provides the melody that drives the song forward, while the vocals join on top of the instruments. However different genres of rock can use instruments that aren't often found in the aforementioned classic and hard rock. For instance, genres such as progressive rock and psychedelic rock tend to push the boundaries of rock music, and typically use instrument such as electric pianos (keyboards), synthesizers, tape loops, theremin, mellotron, and other unconventional instruments that can make one genre unique from the other. Additionally, fusion genres of rock, such as Jazz Fusion or Baroque rock, tend to use instruments that are most prominently used in other genres. Jazz fusion uses piano and saxophone on most occasions, while Baroque rock uses a wide array of classical instruments, such as the Violin, Harp, Double Bass, and Cello.

The Technical Elements

When it comes to the technical elements of rock, we can start to see the true reason why rock is a unique genre of music. The average tempo of a rock song can range anywhere from 110-140 beats per minute, and of course this depends on the type of rock. Subgenres such as Hard Rock and Heavy Metal tend to be speedier than contrasting subgenres such as blues rock or folk rock. As for the time signature*, rock songs usually use a 4/4 time (aka. Common time), as most rock songs tend to have a straight forward beat. There are some exceptions however. For example, the 1973 hit song "Money" by Pink Floyd is composed in 7/4 time, and the 1977 single "We Are the Champions" by Queen is written in 3/4 time. When it comes to key, the most popular keys in rock are C major, D major and G major, each have their reason. C Major is popular as its key signature has no sharp or flat notes, which can provide ease to musicians, especially keyboardists. D Major is known for its common use in "triumphant" pieces of music, while G Major is a very versatile key, and is used in approximately 44% of songs. Additionally, the dynamics of a rock song can vary on the genre, for instance, hard rock and heavy metal have a rough rhythm and are generally full of energy, whilst other genres such as soft rock tend to be much calmer and much less energetic than hard rock and heavy metal. The most common chord progression in rock is I, IV, V, I. This is because rock is known for its use of perfect cadences. Perfect cadences make a song feel resolved, and give it a neat ending.

*a time signature is a way of measuring how many beats are in one bar of a certain musical piece or song.