Use a ruler to investigate how size affects sound. As you explore, keep your ears and eyes open.
Find Out For Yourself
Explore ways to make sound with the ruler.
Now try extending one end of the ruler over the edge of a table and plucking it. Listen carefully to what you hear. Which sounds come from the ruler hitting the table. Which come from the ruler making the air move?
Try making the ruler vibrate so it does not hit the table. Hold the ruler down firmly with a book.
Think about the sounds the ruler might make when a long piece of it extends over the edge of the table and you pluck it. Do you think it might make high or low sounds? Write your predictions about the sound that will be produced by a long, medium and short piece of the ruler. Also write the reasons why you thinks so.
Now think about how a long, medium, and short piece of the ruler will look when it extends over the edge of the table and you pluck it. How will each different length of the ruler vibrate when plucked? Write your predictions and reasons.
Work alone or with a partner to test your predictions.
What did you hear when you compared the sound produced by a long piece of the ruler with the sound of a short piece.
What did you see when you compared the vibrations of a long piece and a short piece of the ruler.
Ideas to Explore
Find object other than rulers that can be extended over the edge of the table and plucked to make sounds. Can you get the sound made by two different vibrating objects to match?
Read a library book that tells more about how animals hear. Share what you learn with someone.
Sound Site ©1999 Science Museum of Minnesota