Sound & Light Waves

Sound & Light Waves

by Mr. Hemenway

​What is Sound?

• ​Sound is a longitudinal wave that can travel through matter (solids, liquids, gases)

• ​CANNOT travel through a vacuum (space)

• ​Caused by vibrating molecules

​Parts of a wave

• ​Wavelength: The distance between one point on a wave and another

• ​Frequency: The number of waves that pass by a given point in one second

​The Human Ear

• ​Outer (Collects Sounds)

• ​Middle (Amplifies Sounds)

• ​Inner (Sends Signals to the Brain)

Multiple Choice

Which mammal has the best hearing?

• Human

• Dog

• Bat

• Porpoise 

​Did you Hear That?

• ​Pitch: How high or low we believe a sound to be

• ​Intensity: The amount of energy that passes through a square meter of space

​When Enough is Enough

​The human ear can withstand up to 120 Decibels of sound before it can be damaged. To put this into perspective:

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​95 DB----------------------------------120DB---------------------------------150DB

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​Lawn Mower

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​Jet Engine

Multiple Choice

Put each item in order from lowest to highest on the decibel chart

• 1.Vacuum Cleaner

  2.Purring Cat

  3.Whisper

  4.A Conversation

• 1. A Conversation

  2.Vacuum Cleaner

  3. Whisper

  4. Purring Cat

• 1.Whisper

  2.Purring Cat

  3.Conversation

  4.Vacuum Cleaner

Let there be Light

• ​Light is an EM wave that can travel through matter AND space

• ​Other types of EM waves:

  • ​Radio

  • ​Microwave

  • ​Infrared

  • ​Ultraviolet

  • ​X-rays

  • ​Gamma

Sources

• ​Light Source: Something that emits light (ex: a candle)

• ​How light interacts with material:

  • ​Reflection: Light bounces off an object's surface

  • ​Transmission: Light passes through an object

  • ​Absorption: Light is absorbed by the material and converted into a new form of energy

​Classification of Material

• ​Transparent: Allows almost all light to pass through and forms a clear picture

• ​Translucent: Allows most light to pass through, but forms a blurry image

• ​Opaque: Allows little to no light to pass through