STEM Tuesday

Catch a Wave!

(This post was originally a STEM Tuesday Spin-Off guest post for the Middle Grade Book Village blog. It fits with this month’s theme of Radio/UV Waves – Applied Physics so I’m recycling it for my Writing Tips & Resources post.)

In STEM Tuesday Spin-Off, we look around at the things in life we often take for granted. We peer behind the curtain, search underneath the hood for the STEM principles involved, and suggest books and/or links to help build an understanding of the world around us. The common, everyday thing will be the hub of the post, and the “spin-offs” will be the spokes making up our wheel of discovery. As our former STEM Tuesday Writing Tips & Resources partner, Heather L. Montgomery often says, we’ll “Go deep!” on a common subject and take a look at its inherent STEM components. 

Today, we will take a closer look at something that is always with us and affects the life of the average 8-14-year-old.

Waves!

Shalom Jacobovitzderivative work: Brocken Inaglory ([[User talk:Brocken Inaglory|talk]]) [CC BY-SA]

The Hub: Waves

Waves, dude! They’re awesome. Riding a wave, either on a board or by body, is exhilarating. Throwing a rock into a calm lake or pond to watch the wave patterns is pretty entertaining and tossing in another rock or two to watch the wave patterns interact takes it to a whole new level. 

Wave motion is pretty cool. The waves created by a sheet flapping in the breeze or the waves generated with a length of rope or a Slinky toy give us hours of entertaining observation. Waves provide both satisfaction from their aesthetic and their physical principles. In short, waves rock!

As cool as the above waves are, there are multitudes of waves in constant motion around us every day and we don’t even need to hit the beach to enjoy them. We notice some of these waves, while others we don’t notice. Yet these waves profoundly affect our modern life every second of every day.  

In today’s Catch a Wave Edition, we’ll talk about these sound and electromagnetic waves and introduce some spin-off resources to learn more and dig deeper into STEM. There are waves all around us, light waves, sound waves, radio waves, microwaves, other electromagnetic waves, and, may I add, waves of middle-grade academic enthusiasm.

Spoke 1: Sound Waves

Sound waves are mechanical waves created by the vibration of a source. The vibrations create longitudinal waves consisting of regions of high pressure and low pressure called compressions and rarefactions that mimic the source vibration. A sound wave must travel from one place to another in a medium and cannot move through a vacuum. 

Sound wave in a cylinder. via Wikimedia Commons.

Transverse Waves

The remaining Spin-Off Spokes are all transverse waves of the electromagnetic spectrum. One of the amazing things about electromagnetic waves is they are a single physical phenomenon that can be separated into types by the characteristic properties associated with their frequency and wavelength.

Electromagnetic wave shape is the more familiar wave shape of crests and troughs, called a sine wave. Transverse waves of the EM spectrum travel at the speed of light in a vacuum.

Spoke 2: Radio Waves

We are all familiar with radio. Turn it on, crank it up, and dance down the hallway on the way to the lunchroom. Radio rocks! Let me tell you, that box that plays our favorite tunes is only a mere sliver of the pure awesomeness of radio waves. Radio waves are the do-it-all, blue-collar, workman of the physical world. Sound, data, and video can be pulsed (modulated) onto a radio wave carrier, transmitted great distances through an antenna, and received by another antenna. A receiver then separates (demodulates) the original signal from the carrier wave and transmits it to an output device.

Let’s say I want to play my wicked new surf guitar solo to a friend who lives six hours away. First, I create the sound into a microphone by playing my new jam. The microphone transforms the vibration of the longitudinal sound wave from the guitar strings into an electromagnetic wave which then gets pulsed/modulated onto a radio wave or microwave. The message on the carrier wave is sent by my antenna great distances at the speed of light until it reaches my friend’s antenna. The antenna catches my message, and the electromagnetic wave is decoded/demodulated from the carrier and sent to a speaker where it is transformed back into a sound wave. Next thing you know, my friend is rocking out to my surf guitar solo. All is good in the world.

A low-frequency message signal (top) may be carried by an AM or FM radio wave.

Look around your school or classroom, there are probably devices on the ceiling or on a table all around that are constantly modulating and demodulating data for your computers and Wi-Fi networks. MOdulating and DEModulating, MOdulating and DEModulating, MOdulating and DEModulating. (Isn’t “modem” an exceptional portmanteau of “modulator-demodulator”?) Did you know that’s what your modem does? Radio waves and microwaves are the carriers of modern life. Technology doesn’t go anywhere without them.

Spoke 3: Microwaves

Microwaves do more than make popcorn or heat up that frozen burrito. With higher energy and higher frequency wave than a radio wave, a microwave can penetrate obstacles that radio waves can’t. Some of the non-food functions of microwaves overlap with the functions of radio waves and the daily utility of these may surprise you. Wi-Fi, Bluetooth, GPS, satellite radio, amateur radio, weather radar, and some broadcasting and communications transmissions, to name a few, are all microwaves. See what I mean? Microwaves make life better, and the bag of popcorn popped in two minutes is truly a bonus.

A satellite dish receives satellite television over a Ku band 12–14 GHz microwave beam from a direct broadcast communications satellite in a geostationary orbit 35,700 kilometers (22,000 miles) above the Earth.

Spoke 4: Infrared Waves

Infrared is such a cool sounding word, science fiction level cool in my book. In reality, though, it simply means “below red”. Infrared waves are often associated with heat, especially the longer wavelength end of the spectrum. These heat waves are given off by fire, heat lamps, and the sun. On the opposite end, the shorter infrared wavelengths don’t give off much heat but do function in one of mankind’s greatest inventions—the remote control! Automatic doors, heat sensors, and night-vision technology are just a few ways we interact with infrared waves in our daily life. Now, where did I put that TV remote?

IR thermography helped to determine the temperature profile of the Space Shuttle thermal protection system during re-entry.

Spoke 5: Visible Waves

We are all familiar with the visible spectrum of electromagnetic waves. They’re the ones we can see and account for the rainbow of colors detected by our eyes. The different frequencies of visible waves are either absorbed or reflected by an object. If the reflected waves are at the longer wavelengths of the visible spectrum, 625-740 nm, the light is red. If the reflected waves are at the shorter end of the spectrum, 380-450 nm, the reflected light is violet. Everything we can see and the multitude of colors originate from the electromagnetic waves of the visible spectrum. You may also have heard about fiber-optic cables used for communication. Fiber optics contain light waves that carry data much like radio and microwaves. Without the visible wave spectrum, we would spend most of our time in the dark.

Spoke 6: Ultraviolet Waves

If the word “infrared” wasn’t cool enough for you, may I present “ultraviolet”? In reality, it’s just an awesome way to say “beyond violet”. Besides the level of word coolness, ultraviolet waves themselves are pretty dang awesome. UV waves are emitted by high-temperature objects, like stars, and help astronomers learn more about how the galaxies are put together. Just as “beyond violet” suggests a deeper shade of purple, ultraviolet waves have their own dark side. UV rays emitted by our sun are the cause of sunburns and prolonged exposure to ultraviolet radiation can cause cancer by changing our DNA.

Of course, there are also the UV rays of lower frequencies emitted from a blacklight bulb which we all know make the school dances spectacular events for white clothing clad individuals.

NASA image of Mira’s bow shock & hydrogen gas tail in ultraviolet, rendered in blue-visible light.

ROUGE WAVES?

There are two additional wave types in the electromagnetic spectrum. These waves, however, are ones you don’t want to expose yourself to regularly. 

X-rays are high-energy waves naturally produced by high-temperature sources, like the sun’s corona. We may be more familiar with medical imaging equipment that uses the power of X-rays to view bone structure. There’s a good reason the radiology technician wears a lead apron for protection while performing X-rays—too much exposure to X-rays can cause serious health problems.

The second waves to avoid are gamma waves. Gamma waves are such high frequency/short wavelength they can pass through the space of a single atom! Unfortunately, they can also destroy living cells. Gamma waves are mainly formed by high-energy objects in space and are absorbed by the Earth’s atmosphere. Lightning, nuclear explosions, and radioactive decay are sources on Earth that can produce gamma rays.

Franquet T., Chung J.H. [CC BY (https://creativecommons.org/licenses/by/4.0)]

Wrap-Up

The final waves needing recognition are the waves of middle-grade enthusiasm and, in particular, the waves of middle-grade enthusiasm for STEM. Keep riding the STEM wave and asking questions about how our world works.

Hopefully, I’ve given you at least six good reasons to appreciate the physical phenomenon of waves. They may not be the easiest thing in the world to understand but they are fascinating.  

Next time you switch on a radio or the TV or get your sprained ankle x-rayed at the hospital, think about all the invisible and visible waves swirling around us every second of every day. Appreciate the STEM-tastic wave and remember this:

Be curious. 

Think about the world around you.

Figure out what makes it tick and work to make it a better place.

CATCH A WAVE!!!