Middle school is a school between the elementary and high schools, which can be between 5 to 7 grades. However, it can vary from one country to the other. For instance, in some countries, middle grades are defined from grade 6 to 8, whereas in other countries, they are defined from grade 5 to 7.
It is sometimes known as the intermediate school as well. In this school, different teachers teach different subjects, which is not the case in primary school classes. For example, if the student has six subjects, they are likely to have different teachers for different subjects. This is helpful because the teacher would have the necessary skill set.
In a sense, the Middle School can be an interface between the elementary classes and a higher one. Sometimes it is also called a Junior School. Thus, the said school students start to adopt the culture of higher classes where they will be recognized as individuals.
The idea of the same was introduced in the mid-sixties, and over time, it gained popularity. The school arranges different teachers for different subjects for middle and high school students. Like the US, some countries have now replaced the middle format having a ratio of 10:1. However, this can vary from one state to the other, as many can have different ratios.