Hypothesize what happens to sound waves when they reach a wall or other solid, flat object. Explain why, based on the behavior of sound waves, a classroom with a tile floor is louder than a library that is carpeted. Think about what it is like to hear things under water. Discuss why you see lightning before you hear thunder during storms. Back to Top Perfect Pitch Have students explore pitches by creating their own homemade instruments.
Students can simply fill a set of glasses with different amounts of water.
Eight glasses with different levels is sufficient for creating an octave of eight notes. After they have done this, strike each glass. They should record the arrangement of the glasses and amounts of water in each glass on paper and add this to their sound notebook. Have students share their tunes and then discuss what they learned from this activity. Explain that the differences in pitch were a result of different heights of columns of air above the water.