Do changing internet provider change IP address?

If you change ISP your IP address will be always change. To be sure of it has been changed and what is your new IP address the best tip is to check out IP locators: http://www.ipaddresslocation.org http://www.find-ip-address.org and not what is your IP address. Then again when you change your ISP visit IP locators again and see what they will tell you about your new IP address. Hope this helps!

Yes, the IP is issued from the ISP and will even different each time you log on as well. Unless, you pay for a Static IP address, then you will have a Dynamic one issued by your ISP, which means it changes periodically. In your case, you IP will be different... yes. But, your MAC Address will be the same, since it's tied to your internet card. People across the internet cannot find you by your MAC however.

Yes. The IP address is assigned by the provider through which you connected and addresses are differently assigned regionally. Static IPs (the same all the time) are more common for fixed severs (paid for) and cable tv company connections through the same provider.