Toys and Physics - Sound and music

7.1 Chicken - Germany

What happens
The chicken cheeps when held on your hand but not in everyone's hand.

Theory and teaching notes
The chicken has a small battery and an audio circuit inside it. When you put the chicken on your hand the contacts on the chicken's feet conduct electricity if your hands are slightly moist and so complete the circuit. Dry hands don't work. You could use it as a simple lie detector. My version of this chicken came from Germany.

7.2 Musical top

What happens
As the top spins it hums and may even play a tune.

Theory and teaching notes
As the top spins kinetic energy of rotation is used to activate an electronic circuit. In the traditional humming top air passing through holes gives a humming sound as the top spins. It can be used both as an example of energy conversion and the stability of rotating objects.

7.3 Playing a saw

What happens
The saw is played by gripping the handle between your knees. The blade is then bent into an S shape and a cello or violin bow is drawn firmly across the smooth edge.

Theory and teaching notes
The more the saw is bent the "tighter" it becomes and the higher the note. It is possible to play simple tunes with practise! The note is loud because the saw has a large flat vibrating area and so moves a lot of air.

7.4 Chicken - Prague

What happens
The chicken sits on top of a small cylinder with a paper membrane stretched across the bottom. A length of string is fixed though the centre of the paper. Using a piece of wood coated with rosin a kind of clucking can be made if the wood is rubbed downwards along the string.

Theory and teaching notes
Stick-slip vibrations are set up and amplified by the paper and cylinder which act as a simple sounding box.

7.5 Falling whistling tube

What happens
When you hold the tube vertical the inner cylinder falls through it and as air rushes through it a sound is made. However if the tube is dropped at the same time there is no sound.

Theory and teaching notes
When the tube and cylinder are both falling the same rate there is no relative motion and so no movement of air through the cylinder. No sound is made. A good example of the constant acceleration of gravity for all objects at a given point on the Earth.

7.6 Singing mug

What happens
The mug is 'silent' when sitting on the bench but when you lift it up it plays a tune.

Theory and teaching notes
The mug "sings" when exposed to light.
There is a light sensor in the base which activates an electronic circuit when light falls on it.
An example of the conversion of light energy to sound energy.

7.7 Wolf whistling Beaver

What happens
When you pick up the beaver or even walk in front of it it wolf whistles at you!

Theory and teaching notes
The beaver wolf whistles when light falls on the light sensor in its chest.
This is a good example of energy conversion and the use of an electronic sensor in controlling an output from a circuit.
It is also possible to buy bird toys from the RSPB that emit bird calls when pressed.

7.8 Animal noises

What happens
When you tip the box upside down it makes a noise like a mooing cow, a baaing sheep or a chirping bird.

Theory and teaching notes
There is an inner cylinder that falls and as the air moves through it a sound is made. You can buy cow noises, sheep or birds. A mooing milk carton is also fun.
An example of the conversion of gravitational potential energy to sound.