2
Space
Walk
Aug 2005
Stephen
Robinson
outside
Discovery
NASA picture
3
Can he call to those inside the
space ship as he works?
NASA picture
4
Connected to the space ship by
a line
Why?
NASA picture
5
Let’s play
some
games !
6
Sound dance
The bunches move along the line.
The children do not move along!
Sound moves this way
steps
7
Sound travels to your ear
The air vibrates
but does not travel from
the alarm to the ear.
Sound
8
Large ears to collect sound
Our ears are
on the side
of our
heads.
We can play
a game to
find out why.
9
?
Why
does
Mittens
look
unhappy?
10
Whales sing
to each
other.
Sound
travels
through
water.
11
12
Bush telephone
game
Sound travels through the string
13
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.
14
Telephones --
The message travels through miles of wires
as an electrical signal.
microphone
loudspeaker
electrical signal
15
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
16
What is this?
What
sound
does she
make?
17
What are these?
What
sound do
they
make?
18
What sound does this make?
How does it
make the
sound?
19
Bells
What
sounds will
they make?
20
Straw oboes
Listen as the straw is snipped.
blow
21
Size matters!
Large things make
___________ sounds
Small things make
___________ sounds
22
New words:
High pitch =
high frequency
Low pitch =
low frequency
23
Size matters!
24
What else changes sounds?
How do you
tune a violin?
Let us try to
make a string
instrument.
25
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.
26
Can you spot the baby?
Sound
has
lots
of
uses
27
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
28
Knowledge about sound helps -
Musical instrument design
and playing them
Sailors find how deep the water is
Building design
so we hear sounds clearly in meetings
so sound does not travel through walls
Sound systems for everyone
radio - CD players
mobile phones - iPods