Historically speaking, bells are very spiritually significant.
Apparently, the bells in churches and temples are a symbolic sound of what exists within each human being, but it's the higher tones that we can't hear that are doing the work. Some believe that when the Soul is near breaking through into the Pure Spiritual realm, the Soul begins to hear a gong sound, or "the big bell sound" as some refer to such a sound.
All of these sounds emanate from the "Word" of God, and the various sounds reflect the less than Pure planes one moves through as one rises in purity. The bells of churches and temples are intended as reminders of what we ought to be listening for in our meditation.
There's a saying, "Every time a bell rings an angel gets his wings"? This is popularized in the movie from 1946, "It's a Wonderful Life" but is said to have been popular amongst children even well over a hundred years ago. Is there some link between bells and angels, possibly enabling their flight? Bells, chimes, jingles, cymbals and gongs are commonly said to be good luck and are often used to ward off evil spirits. Could the ringing of bells really exercise spiritual power, enabling some supernatural influence in the natural realm? While some believe and others doubt, there is a reality beyond superstition.
The Science Behind Temple Bells - Almost every ritual in Hinduism has a scientific reason behind it. Temple bells are no exceptions. Apparently Temples bells make a distinct sound that creates unity of the left and right hemisphere's of the brain. The moment a bell is rung, it produces a sharp and long lasting sound. They believe the echo of the sound from the bell touches the seven healing centres or chakras of the body. So, the moment the bell is rung, the brain goes blank for a few seconds and we enter a stage of trance. In this state of trance, the brain becomes extremely receptive and aware. Thus, when one enters the temple after ringing the bell, we become aware of our spiritual self.