Entry: 11
Date: 9/26
Waves
Chapter 17
8P3A1: Characteristics of EM and
Mechanical waves
1. Wave
• A. a disturbance or vibration that
transmits energy through matter or
space
• B. Carries energy but not the matter
through which it travels
2. Vibration
• A. Repeated back and forth or up
and down motion
• B. How energy travels in a wave
http://www.science-animations.com/supportfiles/slinkyc.swf
3. Medium
• A. is a:
– gas (air, hydrogen, neon)
– liquid (water, )
– solid (anything that has substance like table, book, you)
• B. mechanical waves require a medium to pass
energy through.
4. Types of waves
• A. Electromagnetic
and
Mechanical
5. Electromagnetic waves
• A. Energy waves that can travel
through a medium and empty space
• B. EM spectrum includes: Radio waves,
microwave, infrared, visible light,
ultraviolet, x-ray, gamma ray
• C. All travel at the same speed in the
vacuum of space
D. EM waves are transverse waves
• I. Move back and forth and perpendicular
(right angles) to the direction the wave travels.
6. Vacuum
• A. Emptiness of space that Contains
no matter
• B. Only electromagnetic waves can
travel in a vacuum that’s why
there is not sound in space.
7. Mechanical waves
• A. Energy waves that only travels
through a medium (gas, liquid,
solid)
• B. Allow us to hear
• C. Examples: Sound, seismic waves,
water waves
D. Can be transverse waves
• I. Example: Secondary seismic waves
E. Can be
compressional/longitudinal waves
• I. Move by pushing together and pulling
apart parallel to the direction the
wave travels
• II. Sound waves are compressional
8. Energy of a wave
• A. Energy is transferred from
molecule to molecule as a
vibration in mechanical wave
• B. Energy vibrates the medium, the
medium does not travel
• http://www.wfisd.net/Page/4322
C. Transmit/Transfer
• Transfer to move from one place or object to
another
• transmit, if a substance transmits light, sound,
or energy, the light, sound, or energy can pass
through the material
9. Spectrum
• A range of items put in order.
• Electromagnetic spectrum contains the range
of EM radiation waves