automation – Scripts to repeatedly perform google search without asking for human verification

I am trying to write scripts to perform google search; however, once every 20-30 searches, google as us for human verification, which is very hard for a non-human agent to complete.

I tried the following things to avoid the human verification:

  1. Change LAN IP: Does not work at most of the times.

  2. Use a VPN to switch IP: works

  3. Change browser. It magically works!

What is the rationale behind the option 3? Do you know other methods or apps that works?

Do you think this will be a valid question on more professional SE sites like the stackoverflow?