YOU WILL NEED:
Ground pepper
or flour
Sharp scissors
Balloon
(round, not
sausage-shaped!)
Plastic straw
Plastic
cup or a
thin round
yogurt pot
1 Make a straw oboe. Use your fingernails 3 Practise changing the note from your 8 Insert your straw oboe into the hole on the
to flatten out about 5 cm at one end of the
straw. Now cut the flattened area into a long
point. straw oboe by making your lips more tight
(high note) or loose (low note).
4 Cut the base off the plastic cup or yogurt
pot. side.
5 Cut a cross in the side of your cup, about
2 cm from the base. It needs to be a snug fit
for your straw oboe. Ask an adult to help if
you like.
2 Practise the straw oboe. Lick your lips,
then make them nice and thin (like a mean
witch in a fairy tale). Now put 3 – 4 cm of
the pointed end of the straw oboe into your
mouth and put your lips together around it.
The pointed ends need to be free to vibrate
in your mouth when you blow down the
straw. As the pointed ends vibrate in your
mouth, they make the air in the straw vibrate.
This vibrating air comes out of the straw as a
sound. If you can’t make it work, try moving
the straw a little, more or less inside your
mouth. If you still can’t make it work, you can
just hum down the straw but the results
won’t be quite as impressive.
9 Sprinkle pepper or flour on top of the
stretched balloon surface.
10 Stand the eidophone on a hard surface.
11 Play your straw oboe and watch for
patterns on the membrane. Do the patterns
change if you make a different note?
LOW NOTE
HIGH NOTE
6 Cut the neck off the balloon, at the point
where it is just starting to widen.
7 Stretch the balloon
tightly over the top of
your cup or yogurt pot.
This is going to be the
vibrating membrane.
With the low note, the wavelength is so long
there is no area that is not vibrating, except
the edge, so the flour moves there. With
the high note, the centre and edge are not
moving, so the flour moves to those two
places.
If you have a really big balloon, you can
stretch it over a small plastic bowl to make a
larger eidophone. Does it work better?
With thanks to Helen Arney, Hugh Hunt and Marty Jopson for the ideas and refinement.