I met a man I could not see. But I know he lives not far from me Out past the lake, and up the hill, For when the wind and the birds are still, I stand alone and call \"COME OUT!" And down from the...
Sounds from moving things
Have you ever noticed a change in the \"whistle" a train makes as it rushes by? If you stand by the tracks while the train is passing, the sound gets higher and then lower as the train goes by you. ...
High and low
Zzzeee goes the tiny mosquito as it zips past your ear. HROOM growls a big truck as it rumbles by on the road. The sound the mosquito makes is much higher than the sound of the truck. Why are the...
Make a tin-can telephone
Materials > • hammer > > • nails (3 small) > > • thread (heavy duty--- > > 12 feet; 3.6 meters) > > • tin cans (2) This telephone doesn't need electricity to work. A piece of thread carries...
Sound gets around
A swimming fish seems to glide through the water without making a sound. But it doesn't swim as quietly as you think! Divers swimming underwater hear a loud crack when a large fish flips its tail and...
Now you hear it, now you don’t
A ticking clock sounds loud when you put your ear close to it. But as you walk away, the ticking gets softer and softer---until you can't hear the clock at all. Why does the sound get softer? The...
What is sound?
> Sound comes from just about everywhere--- from friends talking, radios > playing, jet planes roaring overhead. Even your breathing makes a tiny > sound. > > None of these sounds seem very much...
Hear All About It
Hear All About It Hear All About It
What makes these things work?
When you call a friend on the telephone, your voice doesn't really travel through the wire. Your friend hears a copy of your voice---a copy made by electricity. Inside the mouthpiece of your...
Lemon power
You can put your own \"package" of chemicals together to make a battery. A tiny magnet---a compass needle---will show you when the electric current is flowing. Ask a grown-up to use the knife to...