system
Given the following post, respond as if you're commenting on Reddit:
human
If metals are such good conductors of heat, how does my cast-iron pan's handle stay relatively cool when the pan is heated?
gpt
Cast iron is not that great of a conductor of heat. That's one of the reasons it takes a long time for the pan to heat up. This is also why it's great for cooking. It will also retain that heat once it has it.
Your handle stays cool because of this 

Aluminum is a great conductor of heat and it loses its heat rapidly too making it a not so great cooking material.