A LY S S A S H O U LT E S4 T H H O U R

The Electromagnetic Spectrum and The Three Classifications of

Objects

What is the Electromagnetic Spectrum? Why is it important?

The Electromagnetic Spectrum is a list of wave types classified by their wavelengths and frequency.

Without it, almost everything we use wouldn’t exist.

THIS SECTION COVERS THE 6 TYPES OF WAVES IN THE ELECTROMAGNETIC

SPECTRUM.

NOTE: PIECES OF THE SPECTRUM ON PAGE 2 WILL APPEAR IN HERE.

The 6 Waves

Radio Waves

Radio waves are the longest and slowest waves in the spectrum.

Their longer wavelengths allow them to travel out for many miles, which makes them perfect for usage in transmitting AM/FM radio signals.

Top Left: how radio signals work. A station sends out music and speech, translated into binary code and radio waves, to towers that bounce signals off of objects until they find an AM/FM tuner or antenna, which converts them back to music and speech.

Top right: radio wavelengths are nearly straight.

Microwaves

Microwaves are the next wave type in the spectrum, after radio waves.

The waves are used in cooking since they react with the waters in food and cause that water to heat up, cooking the food. They’re also used in radar systems.

Top left corner: a microwave oven uses... microwaves to prepare food.

Bottom left: microwaves have shorter wavelengths and start to bend more.

Top right: a simple radar system schematic. Radar systems incorporate microwaves to track objects in a certain vicinity.

Infrared

Infrared waves are waves after microwaves in the spectrum.

These waves are used in both military and civilian usage. Military uses include night vision and missile guidance. Civilian uses include meteorology, tracking, drying certain objects, and false-color imagery.

Top left: Infrared imagery of a dog. Bottom right corner: Night vision

goggles often employ infrared waves to find objects in darkness.

Bottom left: Infrared waves make up some of the spectrum’s center.

Visible Light

Visible light is the wave type after infrared. This is the smallest section of the spectrum.

This is also the only part of the humans can see without aid of other objects, so anywhere there’s color, you’re seeing visible light!

Bottom left: visible light makes up the middle of the spectrum.

Other four: the iridescence of the bubble, the yellow of the flower, and the color in the cartoon title card are all colored with visible light. The prism bends light into colors we see.

Ultraviolet

Ultraviolet light is the wave type after visible light.

This wave is often seen in sunlight and in tanning booths. Overexposure to UV rays are the cause of sunburn. Long term overexposure increases the chance of skin cancer. Also, looking into the sun can cause cataracts.

Bottom left: Sunscreen, anyone? This man has sunburn, caused by too much UV.

Bottom right: UV rays start the side of the spectrum that can be dangerous if used improperly.

X-Rays

X Rays are the waves after ultraviolet waves.

This wave is often used in medicine as a way to see inside the body to examine for broken bones or to check for cancers.

X-rays are often conducted with others behind a lead shield due to the chance of radiation causing problems.

Bottom left: a broken wrist caught with an x-ray.

Bottom right: X-rays have the second shortest wavelength in the spectrum.

Gamma RaysGamma rays are the last wave type in the spectrum.

This type is also used in medicine. One use it has is to view the organs for any odd mutations. Another is to kill cancerous cells in the body. And another is used to destroy tumors in the brain. (This is called “Gamma-knife.”)

This type is also used to see inside objects, like to view for stowaways in a vehicle.

Bottom left: a “Gamma-knife” machine. A patient’s head goes into the helmet and the sensors in it focus gamma rays on a certain tumor in the brain and gets rid of it. It is a bloodless procedure.

Bottom right: Gamma rays have the shortest wavelength in the spectrum.

THIS SECTION IS OVER CLASSIFICATION OF OBJECTS BY HOW MUCH LIGHT THEY

ALLOW THROUGH.

Three Classes of Objects

TransparentTransparency in objects means that it allows enough light through- without too much scattering- that objects can be clearly seen.

Objects that are transparent include glass, clear plastic, and Saran Wrap.

Humans often use them in windows, cars, preserving foods/objects, and in glassware.

Can you see us? Transparent objects are sometimes harder to see.

TranslucentTranslucent objects are objects that are see-through but, unlike their transparent cousins, only rough shapes can be seen.

Objects that are translucent include frosted glass, water, and tinted windows on a car.

Humans use this to make more private windows, drinking, and for other reasons.

You can see through us, just not that well.

OpaqueOpaque objects don’t allow any light through. Almost all objects that cast a dark shadow are often opaque.

Examples of opaque objects are humans, skateboards, computer systems, and a lot more.

Humans interact in too many ways with opaque objects to list here: talking, driving, riding, and a lot more.

Humans, skateboards, and cars can’t at ALL be seen through.