This document provides definitions and explanations of key internet fundamentals: data is defined as a collection of information that can be numbers, letters, pictures or voice, and is stored on devices with hard drives or memory like web servers, phones, laptops, and tablets. Data is transferred over network cables or wifi when devices communicate and can be measured in bytes, kilobytes, megabytes and gigabytes. The document instructs the reader to identify data sizes and explain how data travels and where it is stored.