Principles of Light Standards
Objective 2: Describe how light can be produced, reflected, refracted, and separated into visible light of various
colors.
a. Compare light from various sources (e.g., intensity, direction, color).
b. Compare the reflection of light from various surfaces (e.g., loss of light, angle of reflection, reflected color).
c. Investigate and describe the refraction of light passing through various materials (e.g., prisms, water).
d. Predict and test the behavior of light interacting with various fluids (e.g., light transmission through fluids,
refraction of light).
e. Predict and test the appearance of various materials when light of different colors is shone on the material.
Principles of Light Vocabulary
Absorption – All light that hits an object is not reflect. It is absorbed by the object (example – a black shirt).
Angle of incidence – The angle that the light ray hits an object.
Angle of reflection – The angle that the light-ray reflects off the object.
Opaque – Does not let light pass through it.
Prism – An object that refracts light and shows the color of the spectrum.
Reflection – Light bouncing off an object.
Refraction – The bending of light.
Spectrum – The colors white light is made of – red, orange, yellow, green, blue, indigo, and violet (ROY G BIV).
Transparent – Allows light to pass through it.
Translucent – Semi-transparent. Light is diffuse (fuzzy) looking as it passes through it.
How is light produced, reflected, refracted, and separated into visible light?
If you were asked to make a list of all the things that give us light, Light bulbs, candles or campfires may be on your
list. The Sun is an important source. Light bulbs are hot, energetic objects. If you have ever touched a light bulb
while it is on, you know it is hot. You know the light bulb needs energy because you have to turn the light switch on
to provide electricity for it. The electricity flows through either a thin metal wire or a gas. The wire or gas glows and
gives off light when heated.
The Moon may seem like a source of light, but it does not provide light like the Sun. It only reflects the light from
the Sun.
Light is energy that travels in rays. Rays we can see is called visible light. There are rays we cannot see. Some do
affect us. We cannot see ultraviolet (UV) rays. They burn our skin when we are in the Sun without Sun block. We
also cannot see infrared rays. We can feel how hot they are on our skin.
Light comes from a light source. Anything that produces light is called a source of light.
~L1~
Examples of light sources.
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The Sun
Stars
Fire
Candle
Electric light bulb
White light is made up of the colors of the spectrum.1 A prism2 is able to separate the light into individual colors.
Fundamentals of Light
We see objects because they either produce light or reflect light. Light is produced by light sources. Our major
source of light is the Sun.
Light waves a medium. Light can travel through the atmosphere and outer space.
Objects can be…
 Transparent3
 Translucent4
 Opaque5
The colors white light is made of – red, orange, yellow, green, blue, indigo, and violet (ROY G BIV).
An object that refracts light and shows the color of the spectrum.
3 Allows light to pass through it.
4 Semi-transparent. Light is diffuse (fuzzy) looking as it passes through it.
5 Does not let light pass through it.
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~L2~
One way heat, light, and sound are alike is that they can be reflected. When you look into a mirror, you see your
reflection.6 If light wasn’t reflected, you wouldn’t see anything. Light strikes something at the angle of incidence.7
It bounces off at the same angle, the angle of reflection.8
Reflection
When you look at a banana, you see yellow. Yellow light is reflected off the banana. You see a blue car because it
reflects blue light. All the other colors are absorbed.9 If all colors are reflected, you see white. If all colors are
absorbed, you see black.
Energy waves can also be refracted.10 When light enters some mediums, it is bent. When light travels through a
liquid, like water, it is bent. Put a straw in water. When you look at it, it appears bent. This is because light travels
slower through water.
With a prism, you can break white light into the colors of the spectrum. The light bends as it goes through the glass
or plastic. We see rainbows because of refraction. Water drops in the atmosphere refracts the light. We see the
colors of the spectrum.
Light bouncing off an object.
The angle that the light ray hits an object.
8 The angle that the light-ray reflects off the object.
9 Take in or soak up; not reflected.
10 The bending of light, refraction.
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~L3~
Light Summary
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We see objects because they either produce light or reflect light and this light enters our eyes.
The colors of the spectrum are red, orange, yellow, green, blue, indigo, & violet (ROY G BIV).
When light travels through certain liquids or solids (window), the light is refracted.
We see colors because that color is reflected off the object. All light is reflected, we see white; all color is
absorbed, we see black.
~L4~