№ 12 · you build it
Both, or nothing
Two switches in a row: the light needs both of them.
- 1Tap the battery, then the button, then the switch.
- 2Tap the switch, then the resistor, then the red light.
- 3Tap the red light, then the battery.
NOW Tap the battery, then the button, then the switch.
What to look for: The light only comes on when the switch is ON and you are holding the button. One on its own does nothing.
Why it works: Both switches are on the same path, one after the other. Electricity has to get through the first one and then the second one, so if either one is open it stops. It takes both.