I understand that Earth distorts space time in 3D, and would like an example (In 2d its a ball on a trampolone etc.) Thanks
I think they are saying that, in the past, how have people safely taken samples? How do you safely take a sample of an unknown solution? What equipment should be work (safety goggles, gloves, etc) and how do you treat the solution? If you have an unknown solution, you should always treat it like an acid, just to be safe. Make sense?
While the above answer does accurately describe the current technology of fire detection/alarm systems, these systems are still governed by the National Electric Code in the US and defined as electrical systems. Most commerical/industrial systems are installed by electrical contractors. If you are attempting to identify for construction contract or depreciation classification, then, fire detection systems are electrical. If it is purely a technological question, lots o semiconductors electronic
