8 Investigating light and sound

EQ: How are light waves and sound waves similar and how are they different? Place an X next to each item that reflects light Water wax paper the moon brand new penny Gray rock tomato soup rusty nail old tarnished penny Leaf crumpled paper clouds smooth sheet of aluminum foil Mirror shiny metal soil Glass Sand Potato skin

Explain 1. Mirror and Laser- When the laser light bounced off the mirror it was reflected at an angle onto the board. 2. The laser light was absorbed and transformed into thermal energy when it hit the wood block 3. Light transmission occurred when the laser light went straight through the clear glass and appeared on the front screen or board 4. When the light refracted as it traveled through the air and then to the water you could tell it had changed speed because the pencil appeared bent.

Light energy is a form of energy that is carried by ___________________ waves. These are waves that can travel through empty space and matter. Electromagnetic waves travel in straight lines called rays and spread out in all directions from the source.

Light energy is a form of energy that is carried by electromagnetic waves. These are waves that can travel through empty space and matter. Electromagnetic waves travel in straight lines called rays and spread out in all directions from the source.

They travel very quickly in 2 They travel very quickly in 2.___ and slow down when they travel through matter. Electromagnetic waves are classified by their 3._______, which is the distance from any point on one wave to a corresponding point on an adjacent wave.

They travel very quickly in space and slow down when they travel through matter. Electromagnetic waves are classified by their wavelength which is the distance from any point on one wave to a corresponding point on an adjacent wave.

The types of electromagnetic waves, in order of decreasing wavelength, are radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays and gamma rays. Electromagnetic waves have many common uses such as cell phones which use microwaves, remote controls that use infrared rays, and gamma ray that can be used for radiation treatment of cancerous cells. Visible light is the only form of electromagnetic waves that can be seen by humans.

Visible light, also known as white light, is a combination of red, orange, yellow, green, blue, indigo and violet light. Three things can happen to light when it hits the surface of matter. The light can be reflected by the matter, it can pass through the matter, or it can be absorbed by the matter. This is determined by the surface it strikes.

When light strikes a transparent object, such as glass, most of the light will pass through. If light passes through 2 different transparent objects, such as water and air, the light will change speed causing the light to bend or refract. Translucent objects, such as plastic Tupperware, allow some of the light to pass through while the rest is either absorbed or reflected. Objects that absorb or reflect all light are known as opaque and include things such as wood. When we see color, we are seeing the reflection of light. A red object will reflect red light and absorb every other color of visible light.

Electromagnetic energy is not the only form of energy that travels in a wave. Sound travels in a wave known as a mechanical wave and unlike an electromagnetic wave; it must have a medium to travel through. Sound waves cannot travel through empty space. Sound is produced when an object vibrates. The vibrating object pushes the particles of matter next to it and causes them to compress (squeeze together). That compressed matter, in turn, compresses the matter next to it.

Sound waves travel in all directions away from their sources Sound waves travel in all directions away from their sources. Like light, sound travels at different speeds through different materials. In general, sound travels faster through solids than through liquids, and faster through liquids than through gases. Sound waves also travel faster through a warmer medium than through a cooler medium. The wavelength, or frequency, of a sound wave determines the pitch of the sound that is heard. A shorter wavelength results in a higher pitch, such as a flute, and a longer wavelength results in a lower pitch such as a bass guitar.

Can travel through space classified by wavelength Light waves Both Sound Waves Can travel through space classified by wavelength Travels slower in objects with greater density Does not require a medium Transfers energy in all directions from the source Changes speed Travels through solids, liquids & gases Higher frequency=higher energy Can be reflected, refracted, absorbed Higher frequency=higher pitch Compresses matter Travels faster in objects with greater density Requires a medium