Curriculum is what is intended to be learnt and taught. For convenience and assurance of scope and sequence, the conventional curriculum is usually organised into arbitrary subjects.
Traditionally, the subjects are often taught in isolation, with the system, school or teacher determining what is taught and when it is taught. The following links lead to an example of content covered in a conventional Science and Social Studies curriculum, along with some guidance on implementing and evaluating curriculum.
The more enlightened 21st Century approaches distinguish between content and process, skills and application, mastery and inquiry. They blend subjects into units of work that have particular emphases, depending on the understandings and skills to be acquired. Students learn to learn by developing inquiry and processing skills, with increasing control over a learning lifetime.
The following link leads to an overview of inquiry-based learning and a modern curriculum framework.