I want you to determine and then make a detailed list of at least 10 uses of electromagnetic waves (EM) that you use. Included on your list the frequencies and historically when these uses were first started. Think carefully, because there may be hidden uses that you are not immediately aware of.
- Hint go study your radio dial.
- How is your cell phone call transmitted?
- List the approximate years that your identified EM waves have been in use
Suppose astronomers wanted to send a message to an alien civilization that is living on a planet with an atmosphere very similar to that of Earth’s. The message must travel through space, make it through the other planets atmosphere and be noticed by the residents of that planet. Discuss with your classmates what wavelengths of the electromagnetic radiation spectrum might be best for sending the message and why? Note that the US congress and the astrophysicist Steven Hawking has in the past warned scientists not to send any messages and reveal our presence to a possible hostile entity in the universe. Find out if we are sending messages into space and then discuss your opinion with your classmates.