Visible and Non-Visible Waves

Both visible and non-visible light are types of energy that travel as waves.

Non-Visible Waves

Cannot be seen with the human eye.

Are electromagnetic waves-they don’t need a medium (solids, liquids, or gases) to travel. They can travel through space.

A part of the Electromagnetic System (EMS).

We are unable to see most of the light waves on the EMS.

Electromagnetic Spectrum

Examples of Non-Visible Waves

Gamma Rays Shortest wavelength,

highest energy. Used in medical

treatment to kill cancerous cells.

X-Rays

Second highest level of energy in the EMS.

Used to check dental and bone problems, used to detect metals in unopened packages.

Examples, Cont’d.

Ultraviolet Rays (UV)

Strong enough to kill bacteria and sterilize equipment.

Enable our skin to produce Vitamin D, but excessive UV exposure causes skin damage/cancer.

Infrared Rays

Can simulate warmth on our skin.

The heat that we feel from the sun, a fire, or a warm sidewalk are infrared waves.

Objects that get warm with use emit infrared waves. The warmer the object, the more infrared waves it is giving off.

Microwaves

• Wave lengths are long enough to cause water molecules in food to vibrate so rapidly that the food cooks quickly.

• Can penetrate haze, rain, snow, clouds, and smoke.

Microwave Tower

Radio Waves

•Wave lengths can be can be as long as a football field or as short as a football.

•Bring music into your car.

•Carry signals for televisions and cell phones.

Radio Wave Satellite

The Visible Light Spectrum

The only electromagnetic waves we can see.

Cones in our eyes are receivers for these tiny visible light waves. The Sun is a natural source for visible light waves and our eyes see the reflection of this sunlight off the objects around us.

The color of an object that we see is the color of light reflected. All other colors are absorbed.

Examples of Visible Light

ROYGBIV

Colors of the rainbow: Red Orange Yellow Green Blue Indigo Violet

Wavelengths in ROYGBIVEach color in the rainbow

corresponds to a different wavelength of the electromagnetic system.

Fun Fact! Black is NOT a color! Black is merely the absence of the wavelengths of the visible light spectrum. So when you are in a room with no lights and everything around you appears black, it means that there are no wavelengths of visible light striking your eye as you sight at the surroundings.

The Light Bulb & The Sun

Light bulbs and the sun are other sources of visible light waves.