This document discusses the fundamentals of sound. It explains how sound travels through air and water from a source to the ear. It also discusses how telephones and mobile phones convert sound to electrical signals that can be transmitted through wires or radio signals and then back to sound. The document covers different sources of sounds like bells and their pitches. It concludes with a summary of the key points learned, such as how vibrating objects produce sound, and how large and small objects affect the frequency and loudness of sounds.

1. Fundamentals of Sound
From musical boxes
to iPods

2. 2
Sound travels to your ear
The air vibrates
but does not travel from
the alarm to the ear.
Sound

3. 3
Whales sing
to each
other.
Sound
travels
through
water.

4. 4
Telephones --
 Are like a sound system
The electrical
signal is
amplified
A microphone
changes sound to an
electrical signal.
A loudspeaker
changes the electrical
signal to sound.

5. 5
Telephones --
 The message travels through miles
of wires as an electrical signal.
microphone
loudspeaker
electrical signal

6. 6
Radio signal
Mobile phones use radio
Sound - electrical signal - radio signal - electrical signal - sound
In one phone the
sound is changed
into an electrical
signal then into a
radio signal.
Sound - electrical signal - radio signal - electrical signal - sound
In the second phone
the radio signal is
changed into an
electrical signal then
into sound.Mobile
phone
beacons

7. 7
What is this?
What
sound
does she
make?

8. 8
What are these?
 What
sound do
they
make?

9. 9
What sound does this make?
 How does it
make the
sound?

10. 10
Bells
 What
sounds will
they make?

11. 11
Size matters!
Large things make
___________ sounds
Small things make
___________ sounds

12. 12
New words:
 High pitch =
high frequency
 Low pitch =
low frequency

13. 13
What have we learned?
 Vibrating objects make sounds
 Sound needs a medium through which to travel
– air, water, string - - -
 The medium vibrates but does not travel with the
sound
 Large vibrations make loud sounds
- small vibrations make quiet sounds
 Large objects make low frequency sounds
- small objects make high frequency sounds
 In strings the frequency of the sound depends
on the length, thickness, and tension.

14. 14
Can you spot the baby?
Sound
has
lots
of
uses

15. 15
Ultrasound is very, very high
frequency sound.
It is used to see inside people
- to see
babies before
they are born
if a heart is
working well
blood flow