AND NOW…

IT’S YOUR TURN!

SOUND AND PHYSIOLOGY

Do you know which are the frequencies we can

hear?

We can hear frequencies between 20 Hz and 20 000 Hz

And other animals?

Some animals communicate using low or high frequencies and we can’ t hear

them. For example bats can emit soundswhose frequncies are from 14,000 to

100,000 Hz

Scale of frequencies

A little surveyNow we try to find out if what we have

said is correct…

Let’s do an

experiment

The Tin can phone

This is a ‘TIN CAN PHONE’

Have you ever used it?

When you speak in the first tin the

sound propagates through the

string and, for this reason, you can

hear the voice in the other tin.

AND NOW… LET’S PLAY BOTTLES

STEP 1

Fill the bottles with water. Each bottle should have a

different quantity of water in it.

STEP 2

Blowing into each bottle, a different sound will be

produced depending on the air column.

EXPLANATION

The air column in each bottle generates a different wave

lenght and therefore a different frequency with a

corresponding sound that is heard when you blow into the

bottle.

This same situation can be created by tying a rope to one

point and shaking it to make waves.

λ=wave lenghtL=air column heightn=natural number

“The choral” of Beethoven

La=A

Si=B

Do=C

Re=D

Mi=E

Fa=F

Sol=G

B B C D D C B A G G A B B A A B B C D D C B A G G A B A G G A A B G A B C B G A B C B A G A D B B C D D C B A G G A B A G G