These vocabulary cards are used for my sound unit. The words include vibration, sound wave, echo, wavelength, frequency, pitch, amplitude, and volume. Each card contains a definition and a picture. I made these to save time because it is much easier to print them on card stock or have them paste them to an index card than to have them write out vocabulary as called for in my curriculum guide. These cards are also sold as part of a set called Energy Unit Vocabulary Cards including all three units (Sound, Light, and Heat