What is included as an essential element in the construction of a bomb?

The essential element included in the construction of a bomb is the power source. A bomb requires a means to initiate or detonate the explosive material, which is typically provided by a power source. This could be in the form of batteries, capacitors, or other energy sources that provide the necessary voltage and current to trigger the detonator or fuse, and consequently, the explosive reaction.

Other elements such as structural casing, while they can play a role in shaping the bomb and containing its components, are not strictly essential for the functioning of the explosive itself in the manner that a power source is. A control panel may be used in more sophisticated devices but is not a fundamental requirement for all types of explosive devices. A barometer does not have any direct relevance to the bomb's detonation process, as it serves a different function entirely, related to measuring atmospheric pressure.