Properties of Light Light travels in straight lines called rays. As we know, they are made up of transverse waves: We also know that light is electromagnetic which means that it is made up of an electric and magnetic component. Laser

Light can create shadows Shadows are places where light is “blocked”: Rays of light

What characteristics do light waves have? Light waves are like other kinds of waves. They have crests, troughs, wavelength, frequency and speed. However, light waves are electromagnetic! Light waves have a component that is electric and magnetic!!

We see things because they reflect light into our eyes We see things because they reflect light into our eyes! This is literally the only way we get to see things! ALL objects we see either create light or reflect light!! Homework

Review-Electromagnetic Radiation Travels at the speed of light Is mostly invisible Carries energy Is made up of transverse waves of different frequencies and wavelengths. Is VERY important to society and is something YOU can’t be without for many reasons

Types of electromagnetic radiation Radio and TV - Great for broadcasting Microwave-Super for cell phones, microwaves Infrared-Think HEAT Visible Light - Yep, it’s how we see Ultraviolet - Invisible, can cause cancer; kills germs Xray- images of bones and teeth; space exploration Gamma - treating cancer (radiation therapy)

Reflection of Light Smooth, shiny surfaces have an accurate reflection. When light bounces off an object or surface, reflects! It always reflects in the same angle that they hit the surface. Materials that reflect light are called opaque. Mirrors are opaque (don’t let light pass through)!

Transmission of Light A material transmits light when it allows the light to pass through it. Transparent materials permit almost permit almost all the light incoming light to pass through. Transparent materials include glass, water and air. Translucent materials scatter light when it passes through. Translucent materials include wax paper, and frosted glass.

Refraction of Light When light rays enter a new medium, they refract or bend. This happens because the waves speed up or slow down when traveling in a different medium.

Example of Refraction Light rays are slowed down by the water Causes the ruler to look bent at the surface The mediums in this example are water and air

-White light will refract when it passes through a prism -White light will refract when it passes through a prism. -This causes it to separate into its colors.

Lenses Lens- a piece of transparent glass or plastic that has a curved surface. -these curved surfaces refract light that pass through. -the shape of the lens determines how it bends. Concave- lenses that curve inward. -light rays spread out. Convex- lenses that curve outward. light rays -light rays come together.

Absorption of Light Materials that absorb light are called opaque. Light rays can be absorbed by an object and transmitted into heat energy. Darker colors absorb more than lighter colors!

Color White light is not a single color; it is made up of a mixture of the seven colors of the rainbow. We can demonstrate this by splitting white light with a prism: This is how rainbows are formed: sunlight is “split up” by raindrops.

How are colors created? A red object reflects red light and absorbs much of the other colors. The color of an object is that color which is reflected not absorbed.

Only red light is reflected Seeing color The color an object appears depends on the colors of light it reflects. For example, a red book only reflects red light: Homework White light Only red light is reflected

The colors of the rainbow: Red Orange Yellow Green Blue Indigo Violet Just remember ROY G. BIV

In different colors of light this shirt would look different: Red light Shirt looks red Shorts look black Shirt looks black Blue light Shorts look blue

A white hat would reflect all seven colors: A pair of purple trousers would reflect purple light (and red and blue, as purple is made up of red and blue): Purple light A white hat would reflect all seven colors: White light