Waves Traveling the Universe

This unit introduces basic properties of waves on the electromagnetic (EM) spectrum, from radio to gamma waves, including visible light waves, and distinguishes between EM and mechanical waves.

Activities

Scene: Flash to Bang

In this Science Scene, three friends discuss different kinds of waves, both mechanical (like sound) and electromagnetic (like the light emitted by lightning).

Duration: Approximately 50 minutes

Lesson: Waves without a Medium

Students compare and contrast two kinds of waves: mechanical, which require a medium of matter to move through, and electromagnetic, which do not.

Duration: Approximately 55 minutes

 

Project: The Electromagnetic Clothesline

Students consider the wide range of frequencies and wavelengths of electromagnetism—especially radio waves—by building a model of the spectrum on a string. Explore how the Earth's atmosphere, ionosphere, and magnetosphere protect humans from space radiation.

Duration: Approximately 45 minutes plus optional 10-minute extension

Writing: Making the Invisible Visible

Students explore what different animals' visual systems can see in infrared, visible, and ultraviolet light. Students reflect on why different animals see differently. Students write a short science fiction or fantasy scene that imagines the action from the point of view of a creature with another visual system.

Duration: Approximately 50 minutes

Conversation: All-Star Alien Hide and Seek

Students discuss the pros and cons of monitoring messages from and sending messages to space using different frequencies on the electromagnetic spectrum, usually in the longest wavelengths such as radio waves.

Duration: Approximately 75 minutes plus optional 30-minute extension

Student View of Visuals and Activities

Some teachers prefer to have students view the slides and other visual assets in this unit directly instead of projecting them in class. Below is a web page to share with students with links to some of same items that are within in the teacher lesson plans, but without the explanatory text for the teacher.

 

• Student Links to Unit E5 Slides and Other Visuals

Teacher Tune-ups

• What types of waves are there, and what do they have in common?
• How can energy travel when matter doesn’t?
• Why do electromagnetic signals (and lots of other phenomena) get weaker with distance?
• How are digital signals a more reliable way to encode and transmit information than analog signals?

wave

noun – a moving disturbance

Let's just stay put and wait for this wave to go by.

radiation

noun – the transferring of energy as waves

Too much of the wrong kind of radiation can kill you, but it's around us all the time!

transmission

noun – sending a signal (often using radio waves)

The new radio station began transmission earlier this year.

electromagnetic

adjective — combining electricity and magnetism

Electromagnetic waves can travel through the vacuum of space. That's why we can see the light of stars many light years away.

spectrum

noun – a range of things or characteristics

This lightbulb puts out a full spectrum of white light, because it emits all the colors from red to violet.

visible

adjective — able to be seen, especially by humans

The visible light part of the spectrum is very narrow, yet it colors the rich world of those of us lucky enough to see it.

frequency

noun – the rate at which something repeats over time

I go to this beach with some frequency, because the waves also come with great frequency. More waves, more surfing!

wavelength

noun – the distance in a wave between one crest and the next, or between two consecutive troughs

Waves with high frequencies also have shorter wavelengths.

medium

noun – a substance (like a solid, liquid, or gas) that the energy of a wave can travel through.

Electromagnetic waves don't need a medium to travel, so we can see them from across the vacuum of space.

analog

adjective — having a variable signal that is continuous in time and amplitude, in contrast with a digital signal

Some people prefer vinyl records over digital music because records store the music and play it back using an analog signal.

digital

adjective — represented by a system that stores data as 1s and 0s in discrete values (rather than a continuous spectrum), in contrast with the continuous nature of an analog signal

The invention of digital music formats made possible everything from compact discs to online music streaming.