Bouncing Sounds:
Hearing Around Corners

Question:

What materials reflect sounds best and create the best echoes?

Hypothesis:

The harder the material, the better the sound bounces and the louder the echo!

Materials: 

• a clock or watch with a quiet tick
• 3-4 similar cardboard tubes (paper towel rolls)
• pieces of materials that might reflect sound, like a sponge, aluminum foil, wooden tile or ceramic tile

---

Special needs:

A very quiet room

Procedure:

1.   Place 2 paper towel rolls flat on the tabletop, at about a 90 degree angle to each other (like an upside down V).

2.    At the end of one tube, place a clock that makes a soft ticking sound.

3.       Let people listen at the end of the other tube, to see if they hear the sound of the clock.

4.       Explain the phenomenon: The sound of the clock travels straight through the first tube, but most of the sound disperses and doesn’t go down the second tube.

5.       Let’s see what happens when we put something at the point where the two tubes meet. How does it sound now?

6.       Add the sponge. Everyone listens.

7.       Explain why it sounds different: The sound of the clock travels through the first tube again, but it bounces off the solid sponge, then is reflected down the second tube – like an echo!

8.       Let’s see what happens if we change from sponge to aluminum foil. How does it sound with the aluminum foil?

9.       Switch to aluminum foil. Everyone listens.

10.       Explain again why it sounds different from the sponge and nothing.

11.    Repeat the experiment with the wooden tile.

12.   Last experiment: let’s see what happens if we use a ceramic tile.  How does it sound now?

13.   Switch the ceramic tile for the wooden tile. Everyone listens.

14.   Explain what happened: The hardest material we used was ceramic tile, and it made the sound bounce the best down the 2nd tube. The echo sounds loudest with the hardest material.

The Science behind it

Sound waves will travel until something stops them, or they disperse.  In our experiment, the sound waves travel through the air in the first tube, bounce off the square of material and continue down the second tube.
 

Conclusions

The hardest materials bounced the sound the best and made the best echo. Echoes are the loudest when the sound waves hit the hardest surface and reflect or bounce.

Here's us at Science Night!

Maxwell

Maxwell is a 5th grade student in Mrs Luke's class.

Thomas

Thomas is a 5th grade student in Mr.Benedetto's class. His favorite subjects are Math and Science. Also he likes to hang out with his friends and play football. He enjoys plays soccer also.

Max

Max is an AWESOME 5th grade dude in Mrs. Carvo's  class.