All sciences are interested in the understanding of the universe and humanity’s place in it; however, natural science is usually focused on helping students understand, through observation and experimentation, how energy and matter combine to affect the physical world.

Education in the United States is mainly provided by the public sector, with control and funding coming from three levels: state, local, and federal, in that order. The common requirements to study at a higher education level in United States will include your admissions essay (also known as the statement of purpose or personal statement), transcript of records, recommendation/reference letters, language tests

Requirements for the PhD program often involve the student having already obtained a Master’s degree. Additionally, a thesis or dissertation primarily consisting of original academic research must be submitted. In some countries, this work may even need to be defended in front of a panel.