538 Doesn't a lightning rod on top of church show a lack of faith?
Cleaner, poorer, healthier, with fewer food options As a result of petrochemical vehicles we will probably reach the same but without the cleaner and healthier part.
Dogs didn't quite get it right. An alpha emitter (americium) is used behind two plates (this assembly is called a cell). The alpha emitter ionizes gas particles (in the air) which allows a stream of electrons to pass between the two plates. This creates an electric current that is sensed by a fairly simple circuit. If smoke enters this cell it disrupts the alpha flow and prevents the stream of ionized particles and hence electrons completing the electric circuit (this makes it fail-safe if the cell fails then the alarm sounds). When the current flow stops, the alarm sounds. Simples ETA The radioactivity (alpha particles) from the radioactive material in the detector ionizes some of the smoke particles No that isn't how the common home detectors work. You have it the wrong way round. The ionizing detectors work by ionizing gases in the air which maintains a current UNLESS smoke is present.
