Deanna Lankford Sound Experiment

Deepkia Menon works as an assistant professor of science education at Towson University in Towson, Maryland. Deanna Lankford is a retired outreach specialist at the University of Missouri in Columbia, Missouri. They conducted many experiments with a 4th grade class to prove that they have misconceptions about sound waves. They based their experiments on these common misconceptions held by elementary students: “sound can only travel through air not through solids or liquids, sound can travel thought a vacuum such as space, sound can be made using no material, and hitting something harder changes its pitch or sound”. They hoped to prove to the students their misconceptions were wrong. They observe the students misconceptions through interactive
First the made groups for the kids so they could work together. The first experiment disproved hitting something harder would change its pitch or sound. To complete this experiment the groups were given two tuning forks of different pitches and the safety precautions when using them. They were told to strike one fork at a time lightly with the mallet they were given then to record a summary of how the tuning forks produced sound. The class said their vibrating caused the sound. Then they were asked what cause the change in sound and the class noticed it was the lengths of the prongs, the longer the prong the lower the pitch the shorter the prong the higher the pitch. The next experiment was to show that sound can move though solids, the solids were rice and sugar crystals. They were placed in a cup with a paper towel to limit the vibrations of sound. The class struck the tuning fork near the solid and noticed that the closer they put the fork to the solid the more it moved. They were told to describe what happened, and what caused them to move. The students came to the conclusion that the sound caused the solid to bounce and vibrate. They then used an app called twisted wave recorder to show the amplitude and frequency of sound waves, they noted though it only shows the waves in 2-D rather than 3-D. the students were then asked to record their voice loudly and softly and determine the differences the pitch made to the wave. The class notice high sound waves are close together where low sound waves are far apart. O show students sound as a mechanical wave they did the following experiments. The students stuck the tuning fork above a cup of water. They concluded sound cause the water to ripple. They did something similar with solids using the cup phones and hear sound travel though a solid to their ear. Concluding