amplitude

Everyday

1. (science) The size of a wave: how high it rises from its middle line. In sound, bigger amplitude means louder; in light, brighter. tree →
2. (formal) Large size or plenty. tree →

In the lessons

In science and maths, amplitude is half the distance from the top of a wave to its bottom. In sound lessons it is linked to loudness; pitch is linked to frequency. Phrases: «high amplitude», «amplitude of a wave».

Examples

• A loud sound has a big amplitude. tree →
• Draw a wave with a small amplitude. tree →
• The earthquake's waves had a huge amplitude. tree →
• Amplitude is measured from the middle line to the top. tree →
• Turning up the volume increases the amplitude. tree →
• The amplitude of the swing got smaller as it slowed down. tree →

Note

For numbers: amplitude = (highest point − lowest point) ÷ 2. Trap: amplitude is loudness, not pitch (pitch is frequency).