What is the difference between google docs and google drive?

In a nutshell: Google Docs are contained in Google Drive, but Google Drive also can have files that you have uploaded from other sources, like videos, and photos.
 
A Google Doc is a document, spreadsheet, presentation or other document made in your Google  account ( Log in to your account at Google.com with your NS email and password).

Google Drive holds all of your Google documents PLUS:

You can add .pdfs, videos, or images to store or share in your Google Drive from  your desktop.

You can create folders of collections of documents that you can share with others

Why Use Google Drive?
Your documents are saved 'in the Cloud' when they are in Google Drive, and can be viewed wherever you have internet access. It's a great backup for your files.