Aspoon can sound like a bell .no ,this is not a riddle .its science. prove it .

What You Need:
Metal spoon
30 inches of kite string (40 inches for an adult)
What You Do:
Tie the handle of the spoon at the midpoint of the string.
Wrap the ends of the string around your index fingers (pointer fingers)
Place your fingers in your ears.
Lean over so that spoon hangs freely and swing the spoon so it taps against a door.
Hit the door again, this time harder.
                              and you can hear it as a bell ( may be church bell sometimes )

Wavelength divides in half and speed stays the same.