Create your own police siren or warning alarm. Have fun creating this 29 piece sound and light kit with a red and blue spinner and buzzer siren. Trigger the alarm with the switch and watch it go off to alert everyone. You could even combine with the maze challenge for a truly alarming experience. Learn electronics and circuit design.
The Connex alarm kit is a good example to show redundancies in a system and how components work in parallel. Both the siren and spinner are connected to the switch and power supply but not to each other, this is a parallel connection. Therefore if one of the wires connecting the spinner to the circuit is not there the siren still sounds but the spinner does nothing and if one of the wires leading to the siren is not connected the siren will not sound but the spinner is unaffected. For those who want to explore how circuits work in series as well the Connex maze challenge is a great introduction. In alarms the alternatives or redundancies are a safety measure so there is a backup in case one is not working.