Awesome question! I love networking. When you enter a URL into your browser, your computer sends the request to your ISP or internet service provider. Your ISP has a HUGE database that coordinates the IP address to the domain name. This database is called a DNS, or Domain Name Service. So when you submit www.google.com to your ISP, they return look in the DNS and find the IP address. The ISP then returns the IP address to you. Your browser then takes the IP and connects you to the server. The server finally send the index.html file to and your browser and renders it as a web page.
This all happens in the blink of an eye. The internet is truly amazing :D
