For example, a high pitch is indicative of a high frequency and a long period. Show how pitch, frequency, and period are related on a guitar. The lower pitched strings will have a lower frequency. This can be seen on the guitar because the higher pitched string will vibrate much more quickly. The guitar can also be used to get students to understand amplitude differences.
Sound waves vibrate.
Have students feel the vibrations in their larynxes as they speak, hum, or sing. Sound travels faster through solids than through liquids or gasses. Take a plastic cup and place a rubber band around it. Place the open end of the cup up to a child's ear and pluck the band. Compare the magnified sound to the sound made by the rubber band when the cup is not up to their ear.