These original EMS pages will be available until May 31, 2011 at which point you'll automatically be redirected to the new pages.
What are waves?
Have you ever ridden a wave in the ocean? Ocean waves travel on the surface of the water. You can see
them and you can feel them. As you swim through the water, you
can even make your own waves.
Have you ever seen a flag on a windy day? The wind creates waves in the flag. Both the waves in the flag
and the ocean waves are waves that you can see. There are other
kinds of waves. We cannot see these waves, but we
experience them every day.
These waves are called electromagnetic
[IMAGE OF ECHO w/Echolocation]
Sound is also a type of wave that we cannot see. Like ocean waves, sound
waves something to travel through like waves through the ocean or through a flag. Sound can travel through air because
air is made of molecules. These molecules carry the sound waves by bumping into
each other, like dominoes knocking each other over. Sound
can travel through anything made of molecules - even water! There is no sound in space because there are no molecules
there to transmit the sound waves. Electromagnetic waves are different from sound
waves because they do not need molecules to travel. This means that
electromagnetic waves can travel through air and solid materials - but they
can also travel through empty space. This is why astronauts on spacewalks
use radios to communicate. Radio waves are one kind of electromagnetic wave.