Observing Sound Vibrations

Elijah finally finished up his energy unit with sounds and hearing. Elijah carried out his last experiment.


Take a can and remove both ends and attach a balloon that has been cut so it can fit over one side of the can tightly. Place a small amount of foil on the balloon. You can make it stick with a bit of glue.





Hold the can to your mouth and speak, scream, hum, etc. through the open end as you shine a flashlight onto the foil. The light should bounce to the wall you are standing near. As you speak the light will move.

More Fun with Sounds

High and low sounds:





We cut the balloon so we could fit it easily over the wide end of the funnel.





We fastened the rubber band to help hold it into place. We took our time patting the balloon while it was lose and then stretched tighter. The sound would change from high to low. Elijah decided that it was very much like our vocal cords. ;) Gotta love experiments.





As he played around with it we found it was acting like an eardrum when we spoke close to the balloon or through the funnel. The sound waves would cause it to vibrate just like the eardrum.


Very fun and easy experiment.




We were reading about sounds that bounce back like echoes and ultrasound. Elijah thought it was very fitting we were learning this after I had just had a sonogram. ;)





With Remy's help he observed how the potential energy was converted to moving energy and how it bounced back and forth after released.

Electromagnet

Eli and I are still playing with sound in his science. :) He made an electromagnet with his father and Remy a few nights ago.


You will need:
* a dry cell
* 3 feet of bell wire
* a large nail or screw





You will then wrap the wire in layers around the screw. Wrap one end of the wire around one terminal of the dry cell. Touch the other end of the wire to the other terminal. The current will flow through the wire causing the nail or scew to become a magnet. Now...pick something up with your electromagnet!











We use many machines that send and receive sound waves. The telephone is one such machine. The telephone depends on an electromagnet to work. An electromagnet is a temporary magnet made by wrapping a coil of wire around a bar of iron. When the electric current flows through the wire, the iron becomes magnetized. When the current is not flowing it stops acting as a magnet.


The telephone changes sound energy into electrical energy. When you talk into the telephone, the sound waves produced by your voice will vibrate against a metal disk against a chamber containing grains of carbon. The disk is the eardrum of the telephone! The sound energy becomes electric energy that flows over the wire to the other person and their electromagnet will turn on and the electric energy is changed back to sound energy! Amazing!


How little thought we put into every day miracles!