At any given moment, kids are hearing lots of sounds all around them. Understanding the connection between sound and vibration is an important science concept for them to know. As a parent, you can introduce your kids to this concept or reinforce what they are learning in school by using tuning forks to conduct simple science experiments.
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Tuning Forks and Water
Though we can’t see air molecules vibrating to produce sound, a denser medium such as water can allow kids to see the vibrations that occur when sound is created. For this experiment, you will need a tuning fork, a glass of water, a rubber mallet and some paper towels. Have your child hit the tuning fork with the mallet and look for vibrations in the air around it, then listen to the sound it makes. Use your hands to stop the vibration of the tuning fork. Next, place the glass of water on some paper towels. Instruct your child to hit the fork again and lower it a few inches into the glass. Your child should notice waves in the water. Explain that these waves are being made from the vibrations that sounds produce.
Hanging Pingpong Ball
With some string, a pingpong ball and a tuning fork, you can show your child that sound is a result of energy in the form of vibration. Cut a piece of string about 1 1/2 feet long and tape or tie one end of it to the pingpong ball. Hold the string away from your body and have your child slowly move the tuning fork toward it. Discuss the results. Repeat the process, this time asking your child to strike the tuning fork before moving it close to the ball. The vibrations from the tuning fork should transfer to the ball causing it to move.
Making a Drum
The head of a drum provides a visual example of the way sound causes vibrations. First help your child make a simple drum. You can use a paper towel roll or an empty can for the base, and a balloon or plastic wrap can be used as the head. Cover an open end of the base with the material of choice and secure with a rubber band. The drum head should be stretched tightly. Have your child sprinkle some salt on top of the drum, then strike the tuning fork, hold it about an inch above the drum, and watch the transfer of vibration cause the salt to move.
Moving Materials with Sound
Once your child has a basic understanding of the connection between vibrations and sound, encourage independent exploration of the amount of energy that can be transferred through a tuning fork. Provide your child with a plastic container and materials such as rice, sand, cereal and gravel. Challenge your child to pour some of each material into the container and determine whether it can be moved through the vibrations caused by the tuning fork on the side of the container.