Activate

Verb

1. To encourage development or induce increased activity; to stimulate.

   "activate the economy"

2. To put a device, mechanism (alarm etc.) or system into action or motion; to trigger, to actuate, to set off, to enable.

   "The pranksters activated the fire alarm by spraying deodorant next to it."

3. To render more reactive; excite.
4. To render a molecule reactive, active, or effective in performing its function.
5. To render a substance radioactive.