1. IP1.29.4 Frequency and pitch © Oxford University Press 2011 Frequency and pitch

2. IP1.29.4 Frequency and pitch © Oxford University Press 2011 The higher the frequency of a sound wave, the higher its pitch. A high pitched sound has high frequency. Higher pitch Pitch and frequency Lower pitch

3. IP1.29.4 Frequency and pitch © Oxford University Press 2011 The greater the amplitude of a sound wave the louder the volume. A loud sound has high amplitude. Louder Volume and amplitude Quieter

4. IP1.29.4 Frequency and pitch © Oxford University Press 2011 Humans can hear sounds in the range of 20 to 20 000 Hz. Sound waves above this frequency are called ultrasound and below this frequency are called infrasound. InfrasoundUltrasound Below 20 Hz20 Hz to 20 000 HzAbove 20 000 Hz Human hearing

5. IP1.29.4 Frequency and pitch © Oxford University Press 2011 Different animals can hear a range of different frequencies of sound. The frequency of a dog whistle is too high-pitched for humans to hear.

6. IP1.29.4 Frequency and pitch © Oxford University Press 2011 A special piece of equipment called an oscilloscope can be used to produce a picture of a sound wave.

7. IP1.29.4 Frequency and pitch © Oxford University Press 2011 If the sound increases in pitch, the waves get closer on the oscilloscope screen. Their frequency has increased.