Ask your young scientist the following:

• what is sound?     —–> with your family try to identify 3 different sounds around your house (i.e., the dog barking, birds chirping, the tv playing, the baby crying, the springs on the trampoline, the water sprinkler, the popcorn popping).
• how does sound travel?    —–> can sounds travel through liquids, solids and gases? In what state of material do you think sounds travel the slowest?
• what is an echo?     —–> when sound waves reach an object, some of the waves bounce back. We sometimes hear these sound waves as an echo. What causes the sound of thunder? **hint, think about lighting and vibrations**

 

   Try this at home:

Seeing Sound

What you will need: a bowl covered with plastic wrap, a pinch of salt or dry sand, a loudspeaker connected to a music system

Procedure:

• put the bowl close to the front of the loudspeaker
• sprinkle some salt or dry sand on top of the plastic wrap
• play some music through the loudspeaker. Music with low notes works best. What happens to the sand/salt?

What happened?

Sound waves from the loudspeaker travel through the air. They cause the air to vibrate, which then causes the plastic wrap to vibrate. The plastic wrap will make a noise, but you probably cannot heat it because of the music. You can see the vibrations making the salt or the sand move and bounce around on the plastic wrap.

 

What is it called when some high-pitched sounds are too high for us to hear? How are ultrasounds used or helpful in our community or daily life?