How do you measure the amplitude of a wave?

You measure the amplitude of a wave by finding the maximum displacement from its rest position.

In more detail, the amplitude of a wave is a measure of how far the particles in the medium move from their rest position when the wave passes through. For a transverse wave, like a water wave or a wave on a string, you can measure the amplitude by looking at the height of the wave crest (the highest point) or the depth of the wave trough (the lowest point) from the rest position, which is the central line where the medium would be if there were no wave.

For a longitudinal wave, such as a sound wave, the amplitude is related to the maximum compression or rarefaction of the particles in the medium. In this case, you would measure how much the particles are compressed or spread out compared to their normal spacing.

To measure the amplitude accurately, you can use various tools depending on the type of wave. For example, with a water wave, you might use a ruler to measure the height of the crest above the still water level. For sound waves, you might use a microphone connected to an oscilloscope, which displays the wave as a graph of pressure against time. The amplitude would be the maximum height of the wave on the graph.

Understanding amplitude is important because it is related to the energy of the wave. A wave with a larger amplitude carries more energy. For example, louder sounds have higher amplitudes, and bigger ocean waves have more energy and can cause more impact when they hit the shore.