Making Sounds With Rulers
Use a ruler to investigate how size affects sound. As you explore, keep your
ears and eyes open.
Materials:
- 1 plastic ruler
- 1 heavy book
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.
discussions