1. Some stuff you should know…
Waves
Some stuff you should know…

2. The basics… Waves are everywhere… all the time.
Everything in science is made of either matter or energy … matter is anything that occupies space and has mass (i.e. rocks, air, ice cream, iguanas, etc…)
So what’s left ?...energy.
Waves move energy but not matter through space.

3. The basics (continued)
Energy can move in 1 of 2 ways… by collisions (think of a bat hitting a ball)
or by vibrations.
Vibrations are repeating types of motion that disturb their surroundings.
A wave is simply the disturbance created by these vibrations (think of a rock dropped in a pond)

4. Two Types of Waves Electromagnetic Waves Mechanical Waves
Do not require a medium (particles in a solid, liquid, or gas) to travel
Light
Radio waves
Mechanical Waves
Require a medium to travel
Sound Waves
Water Waves

5. 2 types of wave movement
1.) Transverse wave – wave in which the displacement of the medium’s particles is at right-angles to the direction of the wave motion.
Water ripples, stadium wave, electromagnetic waves, s-waves of earthquakes

6. 2.) Longitudinal (Compressional) wave
wave in which the displacement of the medium’s particles is in line with or parallel to the direction of the wave motion.
Sound waves, p-waves in earthquakes

7. Longitudinal Compressional Wave
Transverse Wave

8. Some vocabulary Crest – The uppermost part of a wave
Trough – The lowest part of a wave
Amplitude – The height of the crest or the depth of the trough
Wavelength – The distance between 2 successive crests of waves.
Frequency – The number of waves occurring over a period of time.
Measured in hertz (Hz). 1 Hz = 1 cycle/ second

11. Sound Waves Can travel through solids, liquids and gases.
Vibrates particles, which moves next particle, which moves next particle…
Travel faster in solids and liquids than gas (i.e. air)… why?
Because the speed of sound waves relies on how closely the particles are packed together…
The closer the particles, the faster the sound

12. In sound waves… Frequency determines the pitch
Pitch is how high or low the sound is
Frequency is a measure of how many waves pass a point in a given time
Hertz is the most common measurement of frequency and is cycles per second

13. Hearing Thresholds Humans 20- 20,000 Hz Bat 2,000-110,000 Hz
Dogs ,000 Hz
Why can’t humans hear dog whistles?

14. In sound waves… Amplitude measures volume or loudness.
The common unit for sound waves is a decibel (dB)

15. Common Noises Whisper 30 dB Normal Conversation 60-70 dB
Hearing loss after sustained exposure begins at dB
Pain begins at about 125dB
Jet 100 ft, or gunshot 140 dB

16. Electromagnetic (EM) Waves
A type of wave that doesn’t have to pass through a medium (i.e. doesn’t need solid, liquid or gas)
The Sun is a big source… its waves pass through the vacuum of space.
Radiation: the energy that the earth receives from the sun
All forms of energy that travel through space as waves.
The waves that make up all forms of radiation are known as electromagnetic waves.

17. RMIVUXG
Examples include:
Radio waves, microwaves, infrared rays visible light, ultraviolet, X-rays, and gamma rays.
This is the Electromagnetic Spectrum and it is arranged by wave length.

19. Wave lengths Wave lengths determine energy
Radio waves have long wave lengths
LOW energy
Gamma waves have very short wave lengths
HIGH energy

20. Using waves of the EMS
Radiation therapy for cancer patients is high energy.
Past visible light waves can cause damage to humans via skin burns and cell damage
Microwaves don’t actually use microwaves! Most microwaves use radio waves
Remember radio waves are not SOUND WAVES

21. Combining Radio and Sound
Radio waves (EMS) travel through the air without being heard or seen
Sent by transmitter
Antennas pick up radio waves or help receiver pick up radio waves
Receivers transfer radio waves to sound waves in your stereo
You control how the stereo produces the vibrations that cause sound or the frequency of radio waves your stereo receives.

22. Changing waves Diffraction – when a wave bends around a barrier
Water around a boat, light around a table
Reflection- Waves bouncing back
Echo in sound waves
Mirror image in light waves
Refraction- Waves bending as they pass through a different medium
Prisms separate light by refraction
ROY G. BIV

23. Wave Goodbye !